Carlos Fonseca
email: cfonseca@ua.pt

António Alves Da Silva

Joana Alves

José Vingada

Amadeu M V M Soares

A A Da Silva

Reproductive performance of wild boar females in Portugal

Keywords: Reproductive phenology, Litter size, Wild boar management, Sus scrofa, Central Portugal

Reproductive tracts of 214 female wild boars collected in Central Portugal between October and February over the period 1997 to 2001 were examined. From this material, we were able to determine reproductive phenology (conception and birth periods) as well as age and weight of sows at puberty, ovulation rates of adults, foetal sex ratio, levels of intrauterine mortality, final litter size and postnatal mortality. Differences between year, region, age and body weight were analysed. A total of 66.8% of the females examined were gestating or lactating and 96.3% of these weighed >40 kg. The highest proportions of pregnant sows were found in the adult age/weight classes (74%). None of the juvenile females (1 year old and younger) were lactating and only 7% was pregnant. The average number of foetuses/female (4.1±1.2SD) and that of corpora lutea per female (4.6±1.7SD) increased from lighter and younger to heavier and older wild sows. Foetal sex ratio was biased towards males (1.3:1). Observed intrauterine mortality rate (9.7%) and postnatal mortality (6.3%) were among the lowest recorded in European wild boar populations. The productivity rate of the Central Portuguese wild boar population was calculated as 1.1 young per individual in the population. Conception and birth periods did not differ significantly between the considered 4 years. Birth synchronisation was pronounced in all the years, with a peak of births occurring in March.

Introduction

In the last four decades, wild boar Sus scrofa L. populations have shown a significant increase in number and distribution in almost every country within their European range [START_REF] Sáez-Royuela | The increased population of the Wild Boar (Sus scrofa) in Europe[END_REF]Apollonio et al. 2010). In Portugal, as in other European countries, wild boars have shown the same pattern of increase in the number of animals and the range they occupy [START_REF] Fonseca | Ecologia de javali (Sus scrofa Linnaeus, 1758) na região Centro de Portugal (Wild Boar ecology in central Portugal)[END_REF]. Current management strategies seem, in most cases, unable to regulate population increase (Apollonio et al. 2010), perhaps due to incomplete understanding of population demography [START_REF] Spitz | Ongules/ Ungulates 91. SFEPM-IRGM[END_REF][START_REF] Fonseca | Ecologia de javali (Sus scrofa Linnaeus, 1758) na região Centro de Portugal (Wild Boar ecology in central Portugal)[END_REF].

Compared to other European ungulates (e.g. roe deer Capreolus capreolus, red deer Cervus elaphus), wild boars reach sexual maturity earlier, have a relatively short gestation period, higher litter size and short lactation period [START_REF] Fernández-Llario | Body size and reproductive parameters in the wild boar Sus scrofa[END_REF][START_REF] Gerard | Le Sanglier[END_REF][START_REF] Abáigar | Características biológicas y ecológicas de una población de jabalíes (Sus scrofa L.) en el SE Ibérico. (Biological and ecological features of a wild boar (Sus scrofa L., 1758) in South-eastern Iberian Peninsula). PhD Thesis, Universidad de Navarra Abáigar T[END_REF][START_REF] Dzieciolowski | Reproductive characteristics of feral pigs in New Zealand[END_REF][START_REF] Gaillard | Body weight effect on reproduction of young wild boar (Sus scrofa) females: a comparative analysis[END_REF][START_REF] Rosell | Biology and Ecology of wild boar (Sus scrofa L., 1758) from two northeast Iberian populations: Management purposes[END_REF]. Sexual maturity in females is achieved between 5 and 10 months of age, although it is assumed that a minimum body weight of 15-35 kg (e.g. [START_REF] Mauget | Energy intake, growth and timing of puberty in the European wild boar Sus scrofa L[END_REF][START_REF] Appelius | Einflüsse auf die Populationsdynamik von weiblichen Schwarzwild-Frischlingen aus dem nördlichen Regierungsbezirk Braunschweig und dem Forstamt Saupark[END_REF][START_REF] Gethöffer | Reproductive parameters of wild boar (Sus scrofa) in three different parts of Germany[END_REF], influenced by food availability, must be attained before puberty can occur [START_REF] Sweeney | Reproductive biology of a feral hog population[END_REF][START_REF] Aumaitre | Productivité potentielle et reproduction hivernale chez la laie (Sus scrofa scrofa) en milieu sauvage[END_REF]Kanzaki 1991;[START_REF] Bruinderink | Diet and condition of wild boar, Sus scrofa scrofa, without supplementary feeding[END_REF]).

An understanding of female reproductive parameters is one of the most important aspects in management of any wildlife population and better understanding of the reproductive performance of this species would thus improve the basis of management, for instance by modelling the impact of hunting pressure on population dynamics. The purpose of this study was to analyse reproductive parameters of a wild boar female population monitored over four consecutive years in Central Portugal.

Study area

The study area was located in Central Portugal, approximately between the Douro and Tejo Rivers, and covers an area of 23,668 km 2 from 0 to 1,993 ma.s.l. (Fig. 1). This region, which is in the Mediterranean Ibero Atlantic Province (Rivas-Martínez and Loidi 1999), includes two agricultural and forestry administrative subregions: Beira Interior and Beira Litoral (INE 1997).

Beira Interior is characterised as a mountainous region with typical vast rangelands in the foothills, mean annual temperatures of 7.8°C minimum and 16.7°C maximum, and average annual rainfall is 1,137.7 mm (INMG 1991). Its forest covers around 36% of this subregion and is mainly composed of maritime pine Pinus pinaster (57%), eucalyptus Eucalyptus sp. (18%), holm oak Quercus rotundifolia (8%), cork oak Quercus suber (7%), other oaks Quercus sp. (8%) and chestnut Castanea sativa (1%). Its agricultural land represents 27% of the total area and is characterized by medium and large-sized farms of cereals (maize Zea mays and rye Secale cereal, around 42%), vineyards Vitis vinifera (35%), olive trees Olea europaea (19%) and horticultures (DGF 2001;[START_REF] Painho | Cartografia de ocupação do solo, Portugal continental 1985-2000[END_REF].

Beira Litoral, on the Atlantic Ocean coast, has a mean annual temperature ranging from 9.0°C minimum to 18.5°C maximum and an average annual rainfall of 1,399.6 mm (INMG 1990). Its agricultural land is 26% of the total area and the production of small-sized farms includes four major cultures of maize Z. mays, rice Oryza sp., potato Solanum tuberosum and bean Phaseolus vulgaris (64%), olive trees O. europaea (21%) and vineyards V. vinifera (13%). Its forests cover about 48% of the subregion, and the major tree species are Pinus pinaster (63%), Quercus sp. (5%), C. sativa (1%) and more recently Eucalyptus sp. (28%) (DGF 2001;[START_REF] Painho | Cartografia de ocupação do solo, Portugal continental 1985-2000[END_REF].

In terms of diet composition, the principal food items differ between the two subregions. In Beira Interior, the diet is mainly composed of fruits of Quercus sp. (48%) and O. europaea (22%) while in Beira Litoral the principal food items are Z. mays (37%) and O. europaea (34%). The source of Z. mays in Beira Litoral do not come from agricultural damage, but it is primarily provided as artificial food during the hunting season as bait (Alves da Silva 2008).

Wild boar hunting is traditionally carried out in both study areas between October and February mainly by montaria (hunting drive with dogs).

Materials and methods

A total of 365 wild boars (151 males and 214 females) were collected from the study area during four hunting seasons from 1997/1998 to 2000/2001. All females were aged based on tooth eruption, replacement and wear patterns (Matscheke 1967;[START_REF] Boitani | Aging wild boar (Sus scrofa) by tooth eruption[END_REF][START_REF] Pedone | Body size and growth patterns in wild boars of Tuscany, central Italy[END_REF][START_REF] Vassant | Influence de la production de faines et de glands sur les dates de mise bas des laies adultes[END_REF] in three age classes: juveniles (under 12 months old), yearlings (between 12 and 24 months old) and adults (over 24 months old).

In the field, the number of extended teats was recorded and later used in the evaluation of postnatal mortality. Reproductive tracts (uteri and ovaries) were removed and preserved by freezing (-20°C) for laboratory analyses. The physiological stage (pregnant, lactating or non-breedingneither pregnant nor lactating) of females was determined by direct analysis in the field and subsequent ovarian analysis and the number of corpora lutea was counted and recorded to estimate the ovulation rate (in mean number of corpora lutea).

Intrauterine mortality (IUM) was determined following [START_REF] Mauget | Observations sur la reprodution du sanglier (Sus scrofa L.) a l`état sauvage[END_REF] and [START_REF] Abáigar | Características biológicas y ecológicas de una población de jabalíes (Sus scrofa L.) en el SE Ibérico. (Biological and ecological features of a wild boar (Sus scrofa L., 1758) in South-eastern Iberian Peninsula). PhD Thesis, Universidad de Navarra Abáigar T[END_REF] where IUM= (ovulation rate-litter size)/ovulation rate×100. As suggested by [START_REF] Bouldoire | Le Sanglier. Éditions Hatier. Collection Faune Sauvage, Paris Briedermann L[END_REF]Vassant (1989), Pavlov (1991) and [START_REF] Dzieciolowski | Reproductive characteristics of feral pigs in New Zealand[END_REF], the number of piglets surviving 1-2 months after birth can be estimated from the number of suckled teats, assuming that each piglet uses a single teat exclusively and will defend the teat against other piglets until weaning. Thus, the differences between the observed average litter size and the average number of teats extended would give an estimate of the natural postnatal mortality rate. Postnatal mortality (PNM) was calculated after [START_REF] Dzieciolowski | Reproductive characteristics of feral pigs in New Zealand[END_REF] as follows: PNM=(average litter size-average extended teats)/average litter size×100. This way of access to postnatal mortality is still controversial since other authors reported the possibility that piglets could suck the teats of other females from the group [START_REF] Hartmuth | Verhaltensstudien an Wildschweinen im Zoologischen Garten zu Berlin[END_REF][START_REF] Meynardt | Schwarzwild-Report. Mein Leben unter Wildschweinen[END_REF]. Being aware of this issue, caution will be taken in the interpretation and discussion of our results. The population productivity (PR) was estimated after [START_REF] Mauget | Observations sur la reprodution du sanglier (Sus scrofa L.) a l`état sauvage[END_REF] as follows: PR=n×P× number of pregnant females/total sampled animals, where n is the mean number of adult female foetuses and P is the rate of pregnant adult females.

The embryos or foetuses in the uteri of the pregnant females were counted to calculate the potential fertility rate (in mean number of foetuses per litter) [START_REF] Bruinderink | Diet and condition of wild boar, Sus scrofa scrofa, without supplementary feeding[END_REF], sexed (when possible), weighed (to the nearest gramme) and aged. The age of the foetuses (T) in days was determined using the following formula of [START_REF] Vericad | Fetal age, conception and birth period estimation on wild boar (Sus scrofa) in West Pyrenees[END_REF]: T=(Ps 1/3 +2.3377)/0.097, where Ps is the foetus' average fresh weight (g) of the litter. Conception and birth dates were calculated assuming a mean gestation period of 120 days [START_REF] Vericad | Fetal age, conception and birth period estimation on wild boar (Sus scrofa) in West Pyrenees[END_REF][START_REF] Sáez-Royuela | Reproductive trends of the wild boar (Sus scrofa) in Spain[END_REF][START_REF] Rosell | Biology and Ecology of wild boar (Sus scrofa L., 1758) from two northeast Iberian populations: Management purposes[END_REF][START_REF] Markina | Reproductive phenology of wild boar (Sus scrofa L.) in the cantabric mountains (Álava, North Spain)[END_REF].

Statistical analyses

Data analyses were performed using the software package MINITAB® Release 13 (Minitab 2000). Parametric tests (ANOVA) were used when assumptions of the normality (evaluated using the Shapiro-Wilk test) and homoscedasticity (evaluated using the Levene test) of the data (or transformed data) were satisfied. Differences in breeding status, litter sizes and sex ratios between years, subregions and age classes were analysed using the χ 2 test.

A three-way ANOVA without interactions was used to test for differences in mean number of the corpora lutea and mean number of the extended visible teats between years, subregions and age classes.

The seasonal and monthly effects on conception and birth periods were tested by a two-way ANOVA (conception and birth frequencies were first transformed using the square root arcsine transformation).

Finally, within the combined total data set, we investigated the effect of female body weight on the proportions of nonreproductive, pregnant and lactating females, using a one-way ANOVA and linear regression analysis [START_REF] Zar | Biostatistical analysis[END_REF] to explore the relationships between female total body weight and litter size, between ovulation and fertility rates, and female total body weight and mean number of extended teats.

Results

During four hunting seasons (1997/1998 to 2000/2001) 214 females were collected during the driven hunts (Table 1).

Breeding status

From the total of 214 females, 71 (33.2%) were nonreproductive, 115 (53.7%) were pregnant and 28 (13.1%) were lactating. The proportion of breeding females did not vary among hunting seasons (χ 2 =1.234, df=6, p=0.975) or between the subregions (χ 2 = 0.217, df = 2, p = 0.897). Breeding status varied among age classes (χ 2 =87.195, df= 4, p<0.05).

No juvenile females were found lactating and only 7% were pregnant (Fig. 2). The highest percentages of pregnant and lactating females were found in adults, at 74% and 17%, respectively.

Onset of pregnancy

No juvenile females under 32 kg were reproductively active. The three youngest pregnant females that weighed between 33 and 37 kg were killed in the same hunting area (Beira Interior) and represented 7.7% of the females less than 1 year old.

Fertility rate

From 115 pregnant females harvested we collected 481 foetuses. The average number of foetuses per litter was 4.1±1.2 standard deviation (SD) and litter size ranged from two to eight. Litter size did not differ among hunting seasons (χ 2 =14.303, df=18, p=0.709) but differed between subregions (χ 2 =13.246, df=6, p<0.05) and among age classes (χ 2 =8.920, df=12, p<0.05). Female wild boars in Beira Litoral had larger litters (mean=4.2, range=2-8 foetuses, with three and four most frequent) than females in Beira Interior (mean=4.0, range=2-6, with four and five most frequent). Fertility rate or average litter size of females under 12 months old was lower than that of yearlings and of the females more than 2 years old (Table 2).

The number of foetuses of pregnant females was positively correlated with body weight (r=0.48; n=113; p<0.01). Litter size varied (F 5,107 =5.74; p<0.05) among the six weight classes. It increased with weight from 3.0 foetuses per litter among lighter females to 4.9 foetuses per litter among the heaviest females (Table 3).

Sex determination was possible for 141 of 418 foetuses (over 40 days old). The foetal sex ratio was 79 males to 62 females (1.3:1). The foetal sex ratio did not differ significantly (χ 2 =1.82, df=1, p>0.05) from parity or between subregions (χ 2 =0.646, df=4, p=0.422) despite the different ratios (1.06 in Beira Litoral and 1.48 in Beira Interior), both of which were biased toward males.

Intrauterine mortality

An analysis of the ovaries of 80 pregnant females revealed 364 corpora lutea (Table 1). The number of corpora lutea found in the ovaries ranged from two to nine and the mean was 4.6±1.7SD. Ovulation rate and fertility rate were positively correlated (r=0.56; n=55; p<0.01).

A three-way ANOVA without interaction revealed significant differences in ovulation rate between hunting seasons (F 3,73 p<0.05), but no significant differences were found between the subregions (F 1,73 =0.94, p=0.334).

The ovulation rate increased with age (Table 2) and total body weight (Table 3). In the population studied, mean intrauterine mortality was 9.7%. Intrauterine mortality was highest in juveniles (41.8%) and lowest in adult females (13.1%) (Table 2). The same pattern was observed among weight classes (35.8% of 0-34 kg females and 12.3% in 74 kg females) (Table 3).

Postnatal mortality

The mean number of extended visible teats among 39 females was 3.9±1.3SD (range=1-7), which suggests that an average of 3.9 piglets per litter survived the first months of life.

This parameter did not vary among hunting seasons (F 3,32 =0.27, p>0.05) or subregions (F 1,32 =0.01, p>0.05); however, the number of extended teats differed among age classes (F 1,32 =5.63, p<0.05). No extended teats were found in juvenile females. After linear regression it was observed that the number of extended teats was significantly lower in yearlings (3.2±1.4SD; range=1-5) than in females over 24 months (4.2±1.1SD, range=2-7 teats/female). Female total body weight and the number of extended teats were significantly positively correlated (r=0.44, n=38, p<0.05).

From the difference between average litter size and average extended teats, we may calculate that postnatal mortality of piglets in the Central Portuguese wild boar population reached 6.3%. Postnatal mortality of piglets during, approximately, the 2 months after birth was 5.1% in yearling females and 10.2% in older females. Early mortality increased with female age.

Population offspring productivity

In the four hunting seasons, we collected 365 wild boars (151 males; 214 females). Given that the average number of foetuses per adult female (4.6) and the proportion of pregnant adult females (74%), the productivity rate was 1.1 young per individual in the population.

Conception and birth dates-phenology of reproduction

Conception and birth periods did not vary significantly among the four hunting seasons (F 3,15 =0.63, p>0.05). Conception and birth dates varied significantly among the months sampled (F 5,15 =7.24, p<0.05). Fig. 3 shows the seasonal conception and birth distribution pattern as derived by extrapolation from foetal age.

Mating activity seems to begin in August, reaching a peak in November and decreasing in December and January. In this study, the main rut period occurred in November, which represented almost 40% of the pregnant females. The data indicated a pronounced seasonality in births, with a peak in March, which represented 37.5% of the female breeding population. Most piglets (85.4%) were born from February to April inclusive.

Piglet births occurred in the period from December to February (32% of cases), overlapping the main hunting season for wild boar (October to February inclusive).

Discussion

In this study, we found similar reproductive patterns (e.g. percentage of breeding females per age classes) to those reported for several other European wild boar populations [START_REF] Pedone | Body growth and fertility in wild boars of Tuscany, central Italy[END_REF][START_REF] Gaillard | Body weight effect on reproduction of young wild boar (Sus scrofa) females: a comparative analysis[END_REF][START_REF] Rosell | Biology and Ecology of wild boar (Sus scrofa L., 1758) from two northeast Iberian populations: Management purposes[END_REF][START_REF] Herrero | Reproductive and demographic parametres in two Iberian wild boar populations[END_REF].

The proportion of breeding females did not vary significantly among the four hunting seasons or between the two subregions, which reflects a general breeding homogeneity in the Central Portuguese wild boar population. The significant differences obtained in breeding status among age classes were interrelated with the minimum body weight of sexually active females observed in our study, which is similar to those observed in Asian and other European wild boar populations (Table 4); however, the 2007) make refererence to piglets sexually active (15 kg) in Germany, perhaps reflecting the structure and density of the population as well as optimal enviromental conditions for this species.

There is thus found to be a high percentage of nonreproductive juveniles with higher proportions of pregnant or lactating females among yearlings and adults. The higher proportion of breeding adult females might be directly related to the higher body mass and better physical condition of the older females, which has been reported by Fernández-Llario and Mateos-Quesada (1998) and [START_REF] Massei | Diet, food availability and reproduction of wild boar in a Mediterranean costal area[END_REF]. Those authors indicate that the resources available for reproduction increase with the weight and physical condition increment and consequently with age. Several studies showed that the proportion of older females is very important for production in wild boar populations [START_REF] Sáez-Royuela | Reproductive trends of the wild boar (Sus scrofa) in Spain[END_REF][START_REF] Gerard | Le Sanglier[END_REF][START_REF] Boitani | Demography of a wild boar (Sus scrofa L.) population in Tuscany, Italy. Gibier Faune Sauvage[END_REF]. The mean litter size observed in our study reflects the relatively low reproductive capacity of the Central Portuguese wild boar population compared to central and northern European wild boar populations but comparable with other Iberian populations (Table 4) and suggests there is a latitudinal gradient in the reproductive potential of this species, as suggested by [START_REF] Sáez-Royuela | Reproductive trends of the wild boar (Sus scrofa) in Spain[END_REF] and [START_REF] Abáigar | Características biológicas y ecológicas de una población de jabalíes (Sus scrofa L.) en el SE Ibérico. (Biological and ecological features of a wild boar (Sus scrofa L., 1758) in South-eastern Iberian Peninsula). PhD Thesis, Universidad de Navarra Abáigar T[END_REF]. Those authors considered differences in female body size, a consequence of favourable climatic and food conditions to be the main factor producing the reproductive latitudinal gradient. Litter sizes in wild boar populations in Spain are very similar to those observed in Central Portugal, which emphasizes the similarities among wild boar populations on the Iberian Peninsula. In Central Portugal, there was no statistically significant seasonal (1972), [START_REF] Aumaitre | Productivité potentielle et reproduction hivernale chez la laie (Sus scrofa scrofa) en milieu sauvage[END_REF], [START_REF] Boitani | Demography of a wild boar (Sus scrofa L.) population in Tuscany, Italy. Gibier Faune Sauvage[END_REF] and [START_REF] Massei | Diet, food availability and reproduction of wild boar in a Mediterranean costal area[END_REF]. Apart from the low proportion of pregnant juveniles and the low litter sizes of the lighter females, yearlings did not have more than five foetuses/ litter, and only females over 55 kg had more than six foetuses per litter. This emphasised the importance of older females for wild boar population management.

Mean number of corpora lutea per female is much lower than the values reported for wild boar populations in France [START_REF] Mauget | Observations sur la reprodution du sanglier (Sus scrofa L.) a l`état sauvage[END_REF][START_REF] Aumaitre | Productivité potentielle et reproduction hivernale chez la laie (Sus scrofa scrofa) en milieu sauvage[END_REF][START_REF] Aumaitre | Influence du milieu sur la reproduction hivernale et la prolificité de la laie. In: Spitz F, Pépin D Symposium International sur le Sanglier[END_REF], but similar to the values for Spanish populations [START_REF] Garzón-Heydt | Biology and ecology of wild boar (Sus scrofa L., 1758) in Monfragüe Natural Park[END_REF][START_REF] Abáigar | Características biológicas y ecológicas de una población de jabalíes (Sus scrofa L.) en el SE Ibérico. (Biological and ecological features of a wild boar (Sus scrofa L., 1758) in South-eastern Iberian Peninsula). PhD Thesis, Universidad de Navarra Abáigar T[END_REF][START_REF] Rosell | Biology and Ecology of wild boar (Sus scrofa L., 1758) from two northeast Iberian populations: Management purposes[END_REF][START_REF] Herrero | Reproductive and demographic parametres in two Iberian wild boar populations[END_REF]).

The ovulation rates differ significantly between hunting seasons, with the highest value (5.3) occurring in 1998/ 1999, which was a very wet autumn and winter with exceptionally good mast productivity throughout Portugal (Cancela, personal communication). This recognition was emphasised by several authors such as [START_REF] Aumaitre | Productivité potentielle et reproduction hivernale chez la laie (Sus scrofa scrofa) en milieu sauvage[END_REF] and [START_REF] Herrero | Reproductive and demographic parametres in two Iberian wild boar populations[END_REF], who indicated a high positive correlation between ovulation rate and seasonal food availability. Notwithstanding the fact that ovulation rate and the average number of foetuses per litter increase with increasing female total body weight and age class, the two significant effects (p<0.05) of these two factors are the average value of ovulation rate and fertility rate between light and heavy females, and consequently, between young and adult females. The only exception was females whose weight was below 34 kg, which showed a relatively high production of corpora lutea and reflected high intrauterine mortality. The intrauterine mortality rate is among the lowest values reported (Table 4) and is different to other studies and regions, suggesting that intrauterine mortality is a highly variable trait.

Differences observed in intrauterine mortality between age and weight classes were the consequence of the positive correlation between fertility and ovulation rates, which was reported by [START_REF] Abáigar | Características biológicas y ecológicas de una población de jabalíes (Sus scrofa L.) en el SE Ibérico. (Biological and ecological features of a wild boar (Sus scrofa L., 1758) in South-eastern Iberian Peninsula). PhD Thesis, Universidad de Navarra Abáigar T[END_REF]. Generally, as ovulation rate increases intrauterine mortality decreases. That relationship is especially evident when analysed according to age class. While the average production of corpora lutea per female increases from juveniles to adults, intrauterine mortality decreases between the same age classes. The low intrauterine mortality in adult females might be due to their generally better physical condition, which is reflected in their higher body weight. The positive correlation between the fertility and ovulation rates indicated that the increase in average number of the corpora lutea with age is not as strong as the relationship between age and the average number of foetuses per litter.

In the wild boar population studied in Central Portugal, the natural postnatal mortality rate corresponds to 6.3%, which suggests that an average of 3.9 piglets per litter survived the first months of life. This natural postnatal mortality is in the range of 5% to 25%, suggested by Briedermann (1971) and depending on several predation and seasonal climatic factors; however, according to other authors [START_REF] Hartmuth | Verhaltensstudien an Wildschweinen im Zoologischen Garten zu Berlin[END_REF][START_REF] Meynardt | Schwarzwild-Report. Mein Leben unter Wildschweinen[END_REF]) our postnatal mortality estimate can be influenced by the fact that piglets older than 14 days and motherless piglets could suck on teats of other females from the group. If this is the case, the postnatal mortality achieved with this methodology may be underestimated, reaching values higher than thus reported by us but still within the normal parameters for the species.

Adult females showed a higher piglet mortality rate compared to that of yearling sows, which might be due to a smaller litter size in yearling females relative to older sows (as indicated, above) and individual piglets of young sows obtain enough milk and, therefore, are in better condition and have a higher probability of survival.

The offspring productivity rate falls within the production rate for wild boar populations in France [START_REF] Vassant | Influence de la production de faines et de glands sur les dates de mise bas des laies adultes[END_REF], but is higher than the one reported by [START_REF] Mauget | Observations sur la reprodution du sanglier (Sus scrofa L.) a l`état sauvage[END_REF] and [START_REF] Boitani | Demography of a wild boar (Sus scrofa L.) population in Tuscany, Italy. Gibier Faune Sauvage[END_REF] (0.9 and 0.7, respectively). In addition, the low intrauterine mortality contributes to the high production rate of the Central Portuguese wild boar population.

This wild boar population exhibited a seasonal breeding pattern. Such breeding phenomena might be directly related to the strong seasonality in climate, photoperiod [START_REF] Mauget | Synthèse des connaissances actuelles sur la biologie du sanglier, perspectives de recherce[END_REF]) and food availability. Summers are warm and the most limiting season for food resources. In autumn and winter, cold winds and rain are very common (Rivas-Martinez and Loidi 1999), and food availability is high due to C. sativa, Quercus spp. and O. europaea fruit fall. These fruits are high in carbohydrates and lipids, which are essential for reproduction and maintenance of good physical condition [START_REF] Massei | Diet, food availability and reproduction of wild boar in a Mediterranean costal area[END_REF]. As reported by other studies (Sáez-Royuella and Tellería 1987;[START_REF] Garzón-Heydt | Study of a population of wild boar Sus scrofa castilianus Thomas, 1912 in Spain, based on hunting data[END_REF][START_REF] Rosell | Biology and Ecology of wild boar (Sus scrofa L., 1758) from two northeast Iberian populations: Management purposes[END_REF][START_REF] Aumaitre | Influence du milieu sur la reproduction hivernale et la prolificité de la laie. In: Spitz F, Pépin D Symposium International sur le Sanglier[END_REF][START_REF] Vassant | Influence de la production de faines et de glands sur les dates de mise bas des laies adultes[END_REF] in Spain and France, the Portuguese wild boar population also exhibits cyclic sexual activity, with one rutting peak in fall, and one birthing peak in late winter/ early spring (February-April). The highest natality occurred in late winter and most females were pregnant or suckling from April through May. A breeding 'rest' period can occur during the warmer and longer daylight months, referred to by [START_REF] Aumaitre | Influence du milieu sur la reproduction hivernale et la prolificité de la laie. In: Spitz F, Pépin D Symposium International sur le Sanglier[END_REF], [START_REF] Mauget | Synthèse des connaissances actuelles sur la biologie du sanglier, perspectives de recherce[END_REF] and [START_REF] Pépin | Dynamics of reproduction and development of weight in the wild boar (Sus scrofa) in southwest France[END_REF] as the summer anoestrus; however, the presence of three piglets 3 months old and five piglets 6 months old in the January and December Central Portuguese hunting bags, indicates that some females can be pregnant or give birth in summer. In most wild boar populations, the summer births are related to excellent mast crop years and favourable environmental and climatic factors, and also to the puberty body weight and the length of the lactation period [START_REF] Mauget | Observations sur la reprodution du sanglier (Sus scrofa L.) a l`état sauvage[END_REF][START_REF] Singer | Food availability, reproduction and condition of European wild boar in Great Smoky Mountains National Park[END_REF][START_REF] Ahmad | Reproduction in Eurasian wild boar in central Punjab, Pakistan[END_REF][START_REF] Durio | Monthly birth distribution and structure of an alpine population of wild boar (Sus scrofa) in North-West Italy[END_REF].

Data obtained in our study provided the basis for managing the population of wild boar in Portugal as it quantified the temporal patterns of reproduction. These data could be used to model population dynamics and recommend options to manage wild boar populations.

Fig. 1

 1 Fig. 1 Map of the study area (Central Portugal) showing the Beira Litoral and Beira Interior subregions

Fig. 3

 3 Fig.3Mean proportions (%) of conceptions and births in each month of four wild boar hunting seasons(1997/1998 to 2000/2001) in Central Portugal

Table 2

 2 =4.14, p<0.05) and age classes (F 2,73 =4.08, Ovulation rate, fertility rate and IUM in three age classes of female wild boar in Central Portugal (values represent mean±SD)

	%	Non reproductive	Lactating
	100
	75
	50
	25
	0
		Juveniles	Yearlings	Adults
				Age classes
	Fig. 2 Proportions of pregnant, lactating and non-reproductive
	female wild boars in age classes (juveniles: n=39, yearlings: n=
	77 and adults: n=98)

Table 3

 3 Ovulation rate, fertility rate and IUM in six weight classes of female wild boar in Central Portugal (values represent mean±SD)

		Ovulation rate	Fertility rate	IUM (%)
	<34 kg	4.7±2.5 (n=3)	3.0 (n=1)	35.8
	35-44 kg	3.4±1.5 (n=13)	3.1±1.0 (n=8)	7.4
	45-54 kg	4.4±1.5 (n=16)	3.5±0.9 (n=22)	22.3
	55-64 kg	4.5±1.6 (n=19)	4.1±0.9 (n=36)	9.9
	65-74 kg	4.6±1.3 (n=11)	4.2±1.0 (n=20)	7.7
	>74 kg	5.5±2.0 (n=15)	4.9±1.4 (n=26)	12.3

Table 4

 4 Minimum body weight (MBW) of sexually active females, mean litter size, intrauterine mortality and postnatal mortality for European and Asian wild boar populations Median values variation in fertility rate (foetuses/litter); however, the higher number of foetuses/litter observed in Beira Litoral and the wide range of foetuses/litter suggests that the wild boar population in Beira Litoral has a larger proportion of older females than does the population in Beira Interior, which is confirmed by data on population structure. The reproductive capacity of the wild boar population sampled in Central Portugal appears to be dependent on body weight and, consequently, on female age as suggested by Mauget

	Location	Reference	MBW (kg)	Litter size	Intrauterine mortality (%)	Postnatal mortality (%)
	Portugal	Present study	32	4.1	9.7	6.3
	Spain	Sáez-Royuela and Tellería 1987		4.3
		Abáigar 1990				31.0
		Garzón-Heydt 1991		3.9
		Abáigar 1992		4.1	31.0
		Rosell 1998	35	3.6	24.5
			30	4.1	12.5	13.8
		Fernández-Llario et al. 1999		3.7
		Markina et al. 2003		3.9
		Herrero et al. 2008 a		4.0	40.0
				4.0	39.0
	France	Mauget 1972			14.0
		Aumaitre et al. 1982			13.4
		Aumaitre et al. 1984		4.6
		Dardaillon 1988		4.4
		Mauget and Pépin 1991	35
	Italy	Pedone et al. 1991	28	4.9
		Boitani et al. 1995		5.0
	Germany	Briedermann 1971		5.0		5.0-25.0
		Appelius 1995	30	4.4	7.4-8.4
		Gethöffer et al. 2007	15	5.2-7.6	8.0
			15	4.6-6.7	6.0-18.0
	Austria	Martys 1982		5.8		17.0
	Poland	Dzieciolowski 1991		5.2
	Hungary	Náhlik and Sándor 2003		6.7	12.0	55.1-60.9
	Pakistan	Ahmad et al. 1995			16.0
	Japan	Kanzaki 1991	25

a

Acknowledgements We would like to thank the Portuguese Hunter's Federations and Associations for their support during the field work. Thanks to the Portuguese Science and Technology Foundation for the PhD grant support (PRAXIS XXI/BD/13394/97) and thanks to Giovanna Massei and Rory Putman for the paper language and scientific revision and advice. This research complies with current Portuguese legislation.


MPH Sebastian Liersch
email: liersch.sebastian@mh-hannover.de

Vicky Henze

Markus Röbl

Jörg Schnitzerling

Thomas Suermann

Eckart Mayr

Christian Krauth

Ulla Walter

Forty-five minutes of physical activity at school each day? Curricular promotion of physical activity in grades one to four

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

According to the Global Advocacy Council for Physical Activity (2010), the U.S. Department of Health and Human Services (USDHHS) (2008) and the World Health Organization (WHO) (2008), regular physical activity is essential to the healthy development of children and contributes to the reduction of chronic diseases. Children with high activity levels have a lower risk of cardiovascular risk factors such as hypertension, obesity, smoking and type 2 diabetes. Physical activity promotes cognitive ability, mental health, psychosocial competence and personal development (WHO 2008;[START_REF] Salmon | Promoting physical activity participation among children and adolescents[END_REF][START_REF] Biddle | Physical Activity and Children. Review 1: Descriptive Epidemiology[END_REF][START_REF] Sallis | Physical Activity & Behavioral Medicine[END_REF]. A study of German adolescents showed a significant association between sport endurance and psychological well-being, low alcohol and low tobacco consumption [START_REF] Kirkcaldy | The relationship between physical activity and self-image and problem behaviour among adolescents[END_REF]. Pate and co-workers (1995) proposed that a parabolic function is the best estimate to describe the relationship between physical activity and most health outcomes in adults. Assuming this also applies to children, an increase in physical activity should induce a rapid improvement of health, especially in children with low physical activity at baseline. [START_REF] Kelder | Longitudinal tracking of adolescent smoking, physical activity, and food choice behaviors[END_REF] demonstrated that low levels of physical activity or inactivity established during childhood and adolescence will most likely be maintained throughout the life span. Conversely, [START_REF] Twisk | Physical activity guidelines for children and adolescents: a critical review[END_REF] concluded that there was little evidence suggesting that physical activity during childhood and adolescence had an effect on health during adulthood.

Guidelines for programs to promote physical activity have now been established based on the available evidence and practicability considerations. At least 60 minutes of moderate to intense daily physical activity is required to ensure healthy development and health-promoting effects. Activities involving physical inactivity should be limited to two hours per day (USDHHS 2008;[START_REF] Strong | Evidence based physical activity for school-age youth[END_REF][START_REF] Kavey | American heart association guidelines for primary prevention of atherosclerotic cardiovascular disease beginning in childhood[END_REF]. According to the Childhood and Adolescent Health Survey in Germany (KiGGS), only 15.2% of boys and 9.9% of girls aged 7 to 10 years met the target of at least 60 minutes of physical activity per day. In the group of 11-to 17-year-olds, only 28.2% of the boys and 17.3% of the girls met the target (Lampert et al. 2007). As expected, the survey showed that the motor skills of older children and adolescents were better than those of younger children.

However, this typical course exhibited differences in terms of the steepness of the increase in performance for different motor skills. For example, no age-related increases in performance in flexibility (forward bending) and bicycle endurance tests were observed in girls [START_REF] Starker | Motorische Leistungsfähigkeit[END_REF].

Excessive television watching is inversely associated with physical activity. Not surprisingly, children and adolescents with high media consumption are more often affected by obesity (Lampert et al. 2007;[START_REF] Marshall | Relationships between media use, body fitness and physical activity in children and youth. A meta-analysis[END_REF]). Excessive television viewing and computer game playing increases the risk of health impairments such as impaired vision, postural disorders and headaches. The consequences of limited social communication add to the problem.

For children, school is a central part of life and, as such, it is an ideal place to initiate measures to promote physical activity and sports participation. Comprehensive physical activity-oriented school programs are said to have the potential to slow down the age-related decrease in physical activity and to establish lifelong patterns of healthy physical activity behavior. School programs reach virtually all members of an age group independent of parental socioeconomic status, including the children of parents with a low socioeconomic status, who are less likely to participate in extracurricular sports activities (German Sports Federation 2006). According to [START_REF] Siegrist | Sozial ungleiche Gesundheitsrisiken im Kindes-und Jugendalter. Eine aktuelle Bestandsaufnahme der internationalen Forschung[END_REF], school has a homogenizing effect on social gradients, thus initially offsetting or masking the effects of the family home environment. Apart from schools being an important center of activity, including daily physical education instruction in the school curriculum is an important element of physical activity promotion. These programs should help students discover the joy of movement; they should be adapted to the individual student's development level and should promote the development of fundamental and specific motor skills [START_REF] Strong | Evidence based physical activity for school-age youth[END_REF]. From an educational, medical and exercise science perspective, one to two hours of school physical education per week is not enough to ensure adequate physical activity for children and adolescents (Lower Saxony Ministry of Education and Cultural Affairs 2005; Centers for Disease Control and Prevention 1997; [START_REF] Kolbe | An essential strategy to improve the health and education of Americans[END_REF]).

The goal of physical education in primary schools is to promote intentional physical activity and to promote interest in play and sports activities from a holistic approach [START_REF] Jüngst | Schulsport und Sportförderunterricht in[END_REF]. As a school subject, physical education has the interdisciplinary task of promoting the personality development and the acquisition of social value orientations among children and adolescents. Exposure to a variety of different situations that must be mastered individually or in groups provide action-and adventure-oriented experiences that have a positive effect on the development of social competence and other skills. It also provides specific learning opportunities deriving, in particular, from emotionally intense forms of encounter and extensive possibilities to experience through the senses.

The didactic objectives of physical education instruction are [START_REF] Jüngst | Schulsport und Sportförderunterricht in[END_REF][START_REF] Hollmann | Sportmedizin -Grundlagen für Arbeit[END_REF][START_REF] Balz | Gesundheitserziehung im Schulsport. Grundlagen und Möglichkeiten einer diätetischen Praxis[END_REF]):

 to improve motor skills;

 to help students discover the joy of movement and to encourage children's natural urge to engage in physical activity and play;

 to prevent diseases of civilization, especially postural disorders;  to build competence in lifetime physical activities, i.e., those that can be continued throughout life and serve to preserve or promote health;  to convey basic principles and knowledge of sports theory, e.g., about which physical or motor activities achieve which specific physiological changes in the body and the effects of these physical responses on the health.

Health education should focus on sports discipline-specific subjects, interdisciplinary sports subjects, and sportsrelated health subjects such as endurance training, effects of improper training, relaxation exercises for enhanced body awareness, physiological processes of perspiration and respiration, body hygiene, fluid intake, proper sports attire, etc. Children should learn to properly and safely engage in sports and feel at ease when doing so [START_REF] Balz | Gesundheitserziehung im Schulsport. Grundlagen und Möglichkeiten einer diätetischen Praxis[END_REF].

Daily physical education must include effective prevention measures, the quality of which can be assessed based on four quality dimensions: concept, structure, process and outcome quality [START_REF] Kliche | Die Beurteilung der Struktur-, Konzept-und Prozessqualität von Prävention und Gesundheitsförderung[END_REF][START_REF] Dierks | Qualitätsmanagement in der Gesundheitsförderung und Prävention[END_REF][START_REF] Donabedian | Criteria and Standards for Quality Assessment and Monitoring[END_REF][START_REF] Donabedian | Evaluating the Quality of Medical Care[END_REF]. Appropriate instruments and concepts are now available, but problems in their practical implementation still exist [START_REF] Kolip | Körperlich-sportliche Aktivität von Kindern und Jugendlichen in Deutschland[END_REF][START_REF] Bonnen | HEPS Guidelines[END_REF]; Advisory Council on the Assessment of Developments in the Health Care System 2006).

The SPRINT study conducted by the German Sports Federation (2006) empirically assessed physical education in Germany in terms of its objective/structural framework conditions as well as the subjective perspectives of the primary stakeholders. Special problems in elementary schools are the fact that educators teach subjects they are not specialized in and shortcomings in quality assurance. Analyses of physical education programs showed typical gender-specific patterns. At German schools, there is a considerable discrepancy between the sports disciplines and activities offered by the schools and those desired by the students. To ensure the professional competency of the teachers, teacher training and continuing education should be adapted to the changing physical activity spheres of the students in order to ensure that physical education instruction meets the needs of the students of today.

A UK intervention program entitled "Active Programme Promoting Lifestyle Education in Schools" (APPLES) was designed to promote healthy eating and physical activity. The APPLES concept focuses on teacher training, modification of school meals, and the development and implementation of school action plans. In Germany, an intervention entitled "Klasse in Sport" helps ensure that children live and learn in a "movement-friendly" school environment with frequent (daily if possible) supplementary physical activity periods. This is achieved by integrating sports activities in recess periods and physical activity in general classes. In "Klasse in Sport", trained professionals provide one hour (60 minutes) of physical education instruction per day at the cooperating primary schools. Furthermore, deficits in game and sports materials needed for the supplementary physical education activities are eliminated and qualified training and continuing education courses are offered for the teachers.

Fifty schools in Germany are already participating in this intervention.

The following article shows a detailed representation of the intervention of a school-based program to promote physical activity in the childhood. The intervention "fit for pisa" has been developed in response to the demand for scientific evaluation of interventions such as daily physical education. Its goal is to provide quality management-secured, structured and standardized PE instruction by qualified instructors.

Framework curriculum and basic guidelines for physical education instruction in primary schools in Lower Saxony

In Germany, it is the responsibility of the individual states to develop their own educational curricula (www.bildungsserver.de). The state guidelines differ significantly, particularly in terms of the definition and interpretation of terms, statements regarding the educational value of physical education, and interdisciplinary teaching objectives (German Sports Federation 2006). However, almost all of the state curricula specify health as the main justification for school physical education.

The State of Lower Saxony's physical education curriculum will be described as a case example. In Lower Saxony, elementary schools must provide a mandatory two hours of physical education per week. One additional hour of physical activity per week must be ensured through daily movement activity units, which are to be integrated in non-PE classes. Special needs students with psychomotor development problems receive additional special physical education instruction, which is to be delivered as individualized instruction for a total of two class hours per week (Lower Saxony Ministry of Education and Cultural Affairs 2004). Special physical education must be instructed by specially trained professionals. Regular physical education, on the other hand, is often taught by teachers without special training, e.g., homeroom teachers (German Sports Federation 2006).

The "Principles and Guidelines for School Physical Education and Movement Education" is the substantive basis of the physical education and movement activities curriculum for all schools in Lower Saxony. These guidelines specify that school physical education must be adapted to the development level of the children and that it must promote the following competencies (Lower Saxony Ministry of Education and Cultural Affairs 2005):

 Sports competence:

Primarily includes play, movement, physical and sports-related abilities and skills (e.g., improvement of performance, learning to follow and create rules/game rules, music and rhythm education, pupils' organization of their own game and training situations, body awareness, and ecological aspects of movement execution).

 Self-competence:

Mainly involves assuming responsibility and the independent and self-confident input of one's own experiences in differentiated movement activity settings (e.g., developing and implementing one's own concepts of activities, making self-assessments of performance, experiencing and learning to deal with success and failure, overcoming fear, developing strategies for coping with difficult activity situations, communicating feedback, recognizing interests and motives for sports participation, being aware of body image, experiencing well being through physical activity, understanding the benefits of a healthy lifestyle, and learning fairness).

 Social competence:

Primarily involves the ability to engage in group games/play and to interact with others sensitively and responsibly. The children and adolescents should learn to help each other, be considerate of others, and develop team spirit (e.g., to sensitively adapt their actions to the actions of others, to help others and learn to accept help from others, conflict management, making compromises, conflicts with social and cultural differences, and to learn foreign physical activity cultures).

Physical education instruction in primary schools is co-educational. This gives children and adolescents opportunities to acquire social skills that promote cross-gender interaction, to empathize with the perspectives of the other sex, and to understand their own gender roles. For movement education to result in targeted intentional activity, the content and objectives of the curriculum must be clearly defined and documented. In addition to teaching athletic skills and abilities, the curriculum must allow room for reflection on the experiences gained and lessons learned (integration of theory and practice) so that they can be shared in theoretical debates and discussions (Lower Saxony Ministry of Education and Cultural Affairs 2005). Daily physical education in units of 45 minutes per day was implemented as an integral part of the compulsory curriculum for primary school students in the selected grade levels from the beginning to the end of the school year. The school teachers provide the mandatory two hours of physical education required by the state of Lower Saxony. External trainers from ASC Göttingen provide the supplementary three hours of PE/week provided by the intervention (Figure 1). In consideration of the maximum permissible number of class hours for primary school students, the supplementary PE classes replace two reinforcement classes and one regular teaching hour. The regular teaching hour is selected by the school teachers and can vary weekly (depending on necessity the regular teaching hour can be art, mathematics etc.). During a one-year preliminary phase starting in October 2002, framework conditions for the overall project were established and the personnel and spatial structure of the primary schools was assessed. A multi-disciplinary, multi-agency approach was used to ensure the development of a high-quality, effective intervention program [START_REF] Henze | fit für pisa--Mehr Bewegung in der Schule. Untersuchung über den Einfluss und die Wirkungen zusätzlicher Sportstunden auf die körperliche Fitness und das subjektive Wohlbefinden Göttinger Grundschüler[END_REF].

"fit for pisa" intervention project

By the beginning of the 2003/2004 school year, three primary schools contributing two first grade classes each had been recruited to the intervention in Göttingen. The schools entered the project on a voluntary basis in order to ensure the long-term participation of the schools and the support of all persons involved. Eventually, more schools became interested in the project and in the following school year, another two primary schools contributing a total of nine classes participated in the intervention. The daily physical education program is now being conducted in grades 1 to 4 at five primary schools in Göttingen. Until now, the costs for the external trainers (roughly € 2500 per class per school year) have been covered by grants from the Lower Saxony State Chamber of Physicians, the Göttingen School Foundation, the Toto Lotto Foundation, the Sports Physicians Association, and the Association for Health Promotion. In the summer of 2005, a parents' initiative was formed at one of the first intervention schools with the goal of raising enough money from parents to offer additional physical education to classes not participating in the "fit for pisa" project.

Please insert Figure 1 here

Framework and implementation of the daily physical education intervention

Requirements for daily physical education implementation in the framework of the project were defined. All five class hours of physical education are to be taught as single class hours distributed evenly throughout the school week. Physical education classes are to be held outside as often as possible, provided the weather conditions and A multi-perspective teaching approach will be used to achieve this linkage. The goal is that the children should learn to express themselves through physical activity and learn to increase their individual performance through practice and experimentation. The development of a sense of community and learning to deal fairly with others are key learning objectives. Furthermore, the children should learn ways to enhance and preserve their health and fitness and obtain an appreciation for the benefits of a healthy lifestyle. The children will be given opportunities to implement their own ideas, achieve goals independently, and explore individual learning strategies. The intervention program will focus on activities for age-appropriate enhancement of basic motor skills, e.g., activities that allow the children to improve their coordination, balance and spatial orientation, to develop imagination and creativity, to learn safety issues related to physical education and to assess and manage risks, and to recognize their own physical limits. The learning objectives of the "fit for pisa" intervention, which are based on these general intentions, were broken down into five main categories or "learning areas" (Table 1). The specified learning objectives and content of the interventional curriculum are binding for all teachers and external trainers participating in the project. The PE instructors should guide the learning activities in such a way that the children gain an active interest in the content of the lesson [START_REF] Henze | fit für pisa--Mehr Bewegung in der Schule. Untersuchung über den Einfluss und die Wirkungen zusätzlicher Sportstunden auf die körperliche Fitness und das subjektive Wohlbefinden Göttinger Grundschüler[END_REF]. In the "fit for pisa" intervention, physical education instruction for first and second graders focuses on a multifaceted play and movement education concept in which the children are exposed to a wide and unspecialized range of different learning areas. The five key learning areas for grades 1 and 2 are: (1) play;

Movement education

Small games; gymnastics; rhythm & dance; athletic sports; balance

Movement education

Small games; gymnastics; rhythm & dance; athletic sports; balance

Please insert Table 1 here

(2) gymnastics and movement skills; (3) gymnastics, rhythm and dance; (4) running, jumping, throwing and hiking and (5) balance. The key focus of the physical education curriculum for these grade levels is play and movement education (Table 2). Internal differentiation (i.e. respecting differences in individual learning abilities, performance capacities, learning approaches, and paces of learning) is a central objective. The goal is to address the strengths and weaknesses of each individual child. The children should be challenged and encouraged, not over-challenged and discouraged. They will be met at their individual performance level. The learning steps required for the individual pupil should be based on the child's specific learning process rather than on deficits.

Each first and second grade class will be provided one external trainer and one permanent, qualified reference person (teacher) for physical education instruction. New movement experiences, opportunities for self-activity, encouragement to solve movement tasks, sports as an element of healthy lifestyles in everyday life, and imagination-stimulating activities using portable and adaptable equipment and materials are integral themes and contents of the daily physical education intervention. Age-appropriate elements of child play and exploration as well as friendly competition form the basis for the development of motor skills and abilities. Sports such as volleyball and track and field are frequently offered by primary schools, but are not very popular among the students. The pupils frequently prefer sports such as self-defense and badminton, which are rarely offered by schools. Many of the preferred sports (table tennis, badminton, judo, etc.) could be integrated into school physical education classes with no major difficulty. The daily school physical education intervention attempts to include sports preferred by the pupils in order to develop, promote and preserve a sense of fun and enjoyment of movement in the children.

In grades 3 and 4, sports skills will be deepened and new sports will be introduced in an age-appropriate manner.

The children will be introduced to the area of movement, games and sports. This includes the promotion of fitness and training in special techniques in the following learning areas: ball sports/games, gymnastics and apparatus gymnastics, swimming and track and field. In addition, epochal projects such as inline skating, table tennis, climbing, rope skipping, kung fu and acrobatics will be offered from grade 3 on. All motor skill areas will be uniformly used and trained. The age-appropriate introduction to the areas of movement, games and sports will be emphasized in grades 3 and 4 (Table 2). The goal of offering this wide range of activities, which allows the children to discover new sports, is to make school physical education more attractive to all students, male and female. From grade 3 on, the goal is to deepen competency in different sport disciplines that promote specific conditions and expose both girls and boys to new movement activities that they are less familiar with [START_REF] Klewin | Mädchen und Jungen im Schulsport[END_REF][START_REF] Zipprich | Die Bedeutung von Spiel und Sport im Selbst-und Fremdbild von Mädchen und Jungen[END_REF]. In the higher primary school classes, gender-specific differentiation of physical education instruction will be implemented only if, in the course of a class, it becomes clear that differentiation is necessary.

From the 3rd grade on, three specifically trained instructors will be provided for the following core areas: 1) ball sports, 2) gymnastics and dance, and 3) track and field. Each instructor will teach one class per week. The "fit for pisa" intervention addresses the problem of the discrepancy between physical education courses offered by the schools and the wishes and preferences of the students. The exploration of new types of sports is an integral part of the intervention concept. Furthermore, physical education will be instructed without gender differentiation.

Instead, the children will be introduced to sports typically dominated by the opposite sex, for example, gymnastics by girls and hockey by boys.

Please insert Table 2 here

Balance -

Quality management

The "fit for pisa" intervention is based on quality standards. During intervention planning, professional and scientific knowledge from different disciplines was integrated in the concept during a one-year preparatory phase to ensure concept quality. Checklists were developed to document implementation of the daily physical education concept. The initiators developed an accompanying theory-based evaluation system, which was implemented and put into practice from the beginning of the project [START_REF] Henze | fit für pisa--Mehr Bewegung in der Schule. Untersuchung über den Einfluss und die Wirkungen zusätzlicher Sportstunden auf die körperliche Fitness und das subjektive Wohlbefinden Göttinger Grundschüler[END_REF].

The schools must have a gymnasium or sports hall of adequate size and adequate sports equipment and materials to ensure adequate structural quality of the daily physical education program. Since most of the primary schools did not meet this requirement, we inspected each school in advance to determine to what extent outdoor areas, classrooms and school auditoriums could be used as alternative physical education facilities. The cooperating sports club (ASC Göttingen) provided the external trainers and teacher training (certification). ASC Göttingen also provided sports materials and equipment to schools lacking these materials [START_REF] Henze | fit für pisa--Mehr Bewegung in der Schule. Untersuchung über den Einfluss und die Wirkungen zusätzlicher Sportstunden auf die körperliche Fitness und das subjektive Wohlbefinden Göttinger Grundschüler[END_REF].

Teacher training is held at the participating schools once a month to promote standardized implementation and quality management (process quality) of the intervention program. Unlike many other primary school teachers, the intervention teachers have basic certification in physical education (German Sports Federation 2006).

Additional monthly meetings are held so that any problems, deviations or other issues occurring in the classes can be discussed. Checklists are provided for the teachers and external trainers to document the content and objectives of each lesson (strength, speed, endurance, flexibility, orientation, etc.). Other aspects of teacherstudent interaction (e.g., class disruptions, tardiness and non-participation) and the amount of effective class time are also noted on the checklists. Supervisors managed by the sports club evaluate the checklists at regular intervals. Quarterly meetings are held to discuss theoretical concepts and practical possibilities. Didactic and methodological approaches and spatial organizational variations are main areas of focus. Continuing education courses with external trainers (e.g., on the construction and management of movement activity landscapes or on strengthening one's own health resources) are also offered by the project team. This serves to ensure process quality and to involve the teachers in more project events. Teachers cannot implement the intervention concept at school with conviction unless they themselves are convinced of its merit and unless the concept reflects their personal attitude towards physical education.

Evaluation

In order to evaluate the intervention outcomes (outcome quality), data on relevant parameters have been gathered [START_REF] Walter | Weißbuch Prävention! Beweglich[END_REF]. The results of the evaluation, including the health and economic analyses, will provide a basis for future decisions and investments regarding education, health and sports.

Conclusions

The "fit for pisa" intervention has responded to the many demands for daily physical education in primary school and implemented them into practice at five primary schools in Göttingen, Germany. Standardized implementation of the intervention by specifically trained external trainers and the use of a specifically developed and mandatory curriculum serves to enhance the quality of instruction. This is ensured by concomitant quality management and continuous supervision. This quantitatively enhanced school physical education intervention concept focuses on integration of the interests of the students and exploration of new types of sports. Classes are organized according to the availability of school facilities and resources, including previously unused alternatives [START_REF] Henze | fit für pisa--Mehr Bewegung in der Schule. Untersuchung über den Einfluss und die Wirkungen zusätzlicher Sportstunden auf die körperliche Fitness und das subjektive Wohlbefinden Göttinger Grundschüler[END_REF]. The sustainability assessment performed one and two years after completion of the intervention serves to assess the impact of the intervention on health-and education-related outcomes. Gender-specific and socioeconomic variables are specifically considered and analyzed. In addition, the structural conditions for daily physical education, obstacles to it and their solution will be systematically analyzed in order to obtain evidence for comprehensive and coordinated implementation of a movement-oriented activity program and to estimate the amount of investments needed [START_REF] Walter | Weißbuch Prävention! Beweglich[END_REF]. The curricular integration of daily physical education in school-a place where children spend a large part of their lives-will promote physical activity at all schools. As it was implemented in the school setting, the intervention will contribute to improving the equality of opportunity for all children, including those from socially disadvantaged communities, which frequently lack an adequate infrastructure of recreational facilities encouraging physical activity.

However, coordinated comprehensive national and international programs to promote physical activity and sports participation are still lacking. Despite the active involvement of cooperation groups, it must not be forgotten that the responsibility for physical education and movement education for children in Germany falls under the jurisdiction of each state's Ministry of Culture and Education.

"

  fit for pisa" is an intervention project launched in Göttingen, Germany in 2002 to promote daily physical education in schools. Participating students receive three 45-minute hours of PE/week in supplement to the mandatory two 45-minute hours required by the state of Lower Saxony. The daily physical education program was initiated by a local sports club, ASC Göttingen von 1846 e.V. (hereinafter referred to as "ASC Göttingen"), the State Chamber of Physicians, and the Göttingen Department of Public Health in collaboration with the Georg August University of Göttingen in 2002 and has been continued without interruption since the 2003/2004 school year.

Figure 1 :

 1 Figure 1: fit for pisa intervention

  from the participating institutions since the start of the intervention. The scientific evaluation will provide insight into the health and education-related effects and sustainability of four years of daily physical education in primary schools. The evaluation should provide information of the benefits of the intervention for specific target groups, such as boys, girls, the children of parents with a low socioeconomic status, children with physical impairments, and overweight or obese children. This information can be used to develop practice-oriented action plans for specific communities, grade levels and subgroups, etc. Furthermore, quality testing increases the attractiveness of the individual schools. A medical history and examination, sports test for assessment of motor development, and standardized questionnaire for assessment of emotional state in all students have been performed annually since the 2003/2004 school year.Furthermore, quality of life, attention and concentration, violent behavior, recreational behavior and physical activity are assessed at the end of the 4th, 5th and 6th grade. Most of the tools used for the analysis are standardized and validated instruments for which representative reference data on children in the corresponding age groups are available. A parental questionnaire is used to assess the child's medical history and the family's physical activity and socioeconomic status. Moreover, the school principals, teachers, external trainers and parents are surveyed on the potentials of and barriers to daily physical education in guideline interviews. Surveys conducted at the end of the 5th and 6th grades serve to test the sustainability of the effects of the intervention.The evaluation of the sustainability of effects and cost effectiveness of daily school physical education (2007 to 2010) is supported by a grant from the Federal Ministry of Education and Research

for pisa: Daily physical education at primary schools fit for pisa: Daily physical education at primary schools Specific types of sports Ball sports; gymnastics; rhythm & dance; athletic sports Specific types of sports Ball sports; gymnastics; rhythm & dance; athletic sports Specific types of sports Ball sports; gymnastics; rhythm & dance; athletic sports

	fit
	45 min/day	45 min/day	45 min/day	45 min/day	45 min/day
	External	School	External	School	External
	trainers	teachers	trainers	teachers	trainers
	Grade 1 Grade 1 Grade 1	Grade 2 Grade 2		Grade 3 Grade 3	Grade 4 Grade 4

Table 1 : Learning objectives of the "fit for pisa" intervention (adapted from Henze 2007) Skills and abilities Learning objectives of the "fit for pisa" intervention

 1

	Specific sports-related skills	 Acquire skills in different movement patterns
		 Improve motor skills
		 Acquire skills in sports-specific techniques
		 Improve agility
		 Learn team games
		 Improve skills using large and small sports equipment
		 Movement, dancing to music
		 Gain experience moving in and out of the water
	Physical motor skills	 Learn body awareness and control
		 Develop physical experiences
		 Learn to make self-assessments of oneself and one's abilities
		 Improved coordination and fitness
	Social skills:	 Enjoyment of sports activities
		 Acquire social competence
		 Develop cooperation skills
		 Learn to deal with winning and losing
	Affective skills	 Discovering the fun and enjoyment of sports
		 Dealing with happiness, anger, irritation and sadness
		 Increase motivation to learn and achieve
	Cognitive skills	 Learn and execute a variety of movement and game forms
		 Learn to solve problems alone and in a group
		 Learn safety issues related to physical education and to assess and
		manage risks
		 Learn to make self-assessments of one's own skills and abilities
		 Learn and abide by rules

Table 2 : Learning areas and contents of the intervention according to grade level "fit for pisa" intervention Grades 1 and 2 Movement education Grades 3 and 4 Specific types of sport Learning area Subject Contents Subject Contents

 2

	Games	Small games Running, chasing and catching	Ball sports	Ball and team sports:
			games:		 Mini-basketball
			 Catch		 Soccer
			 Simon says, etc.		 Hockey
			Team games:		 Table tennis
			 Dodgeball		 Soft tennis, etc.
			 Treasure hunt, etc.
	Gymnastics and	Apparatus	Explore and practice a range of	Apparatus	Learning fine-motor skills:
	movement	gymnastics	different movement activities	gymnastics	 Forward and backward
			using large and small		rolls
			equipment:		 Flips
			 Apparatus obstacle		 Swinging on still rings
			course		 Vault
			 Balance exercises
			 Swings and rockers
			 Climbing and hanging

for pisa: Daily physical education at primary schools fit for pisa: Daily physical education at primary schools Specific types of sports Ball sports; gymnastics; rhythm & dance; athletic sports Specific types of sports Ball sports; gymnastics; rhythm & dance; athletic sports Specific types of sports Ball sports; gymnastics; rhythm & dance; athletic sports Movement education Small games; gymnastics; rhythm & dance; athletic sports; balance Movement education Small games; gymnastics; rhythm & dance; athletic sports; balance Figure 2: fit for pisa intervention Table 3: Learning objectives of the "fit for pisa" intervention (adapted from Henze 2007) Skills and abilities Learning objectives of the "fit for pisa" intervention

  Specific sports-related skills  Acquire skills in different movement patterns  Improve motor skills  Acquire skills in sports-specific techniques  Improve agility  Learn team games  Improve skills using large and small sports equipment  Movement, dancing to music  Gain experience moving in and out of the water Physical motor skills  Learn body awareness and control  Develop physical experiences  Learn to make self-assessments of oneself and one's abilities  Improved coordination and fitness Social skills:  Enjoyment of sports activities  Acquire social competence  Develop cooperation skills  Learn to deal with winning and losing Affective skills  Discovering the fun and enjoyment of sports  Dealing with happiness, anger, irritation and sadness  Increase motivation to learn and achieve Cognitive skills  Learn and execute a variety of movement and game forms  Learn to solve problems alone and in a group  Learn safety issues related to physical education and to assess and manage risks  Learn to make self-assessments of one's own skills and abilities  Learn and abide by rules

	fit
	45 min/day	45 min/day	45 min/day	45 min/day	45 min/day
	External	School	External	School	External
	trainers	teachers	trainers	teachers	trainers
	Grade 1 Grade 1 Grade 1	Grade 2 Grade 2		Grade 3 Grade 3	Grade 4 Grade 4

Table 4 : Learning areas and contents of the intervention according to grade level "fit for pisa" intervention Grades 1 and 2 Movement education Grades 3 and 4 Specific types of sport Learning area

 4

		Subject	Contents	Subject	Contents
	Games	Small games Running, chasing and catching	Ball sports	Ball and team sports:
			games:		 Mini-basketball
			 Catch		 Soccer
			 Simon says, etc.		 Hockey
			Team games:		 Table tennis
			 Dodgeball		 Soft tennis, etc.
			 Treasure hunt, etc.
	Gymnastics and	Apparatus	Explore and practice a range of	Apparatus	Learning fine-motor skills:
	movement	gymnastics	different movement activities	gymnastics	 Forward and backward
			using large and small		rolls
			equipment:		 Flips
			 Apparatus obstacle		 Swinging on still rings
			course		 Vault
			 Balance exercises
			 Swings and rockers
			 Climbing and hanging
			 Hopping and jumping,
			etc.
	Gymnastics,	Rhythm and	Fundamental skills in	Rhythm and	Simple forms of rhythmic
	rhythm & dance	dance	gymnastics, rhythm & dance	dance	gymnastics
			 Synchronized		 Synchronized
			movements		movements
			 Singing, etc.		 Small dances, etc.
	Running,	Athletic	Practicing elementary athletic	Athletic	Practicing elementary athletic
	jumping,	sports	skills:	sports	skills:
	throwing and		 Using running tracks		 Orienteering
	hiking		 Participating in races		 Sprints
			 Throwing and catching		 Long jump
			with a partner, etc.		 Shot put, etc.
	Balance	Balance	Balance exercises:	Balance	-
			 Balancing on barrels
			 Balancing on a wobble
			board
			 Learning to use
			pedalos, etc.

Conflict of interest

The authors declare that they have no conflict of interest.