Nicolas Salliou
email: nicolas.salliou@gmail.com

Rallou Thomopoulos

MODELLING MULTICRITERIA ARGUMENT NETWORKS ABOUT REDUCED MEAT CONSUMPTION

Keywords: Food diet modelling, Argumentation systems, Animal food product, Consumer, Food choice criteria

A second nutrition transition seems to emerge towards more plant-based diets, curving meat consumption in developed countries in the beginning of the XXI century. This shift suggests that logical arguments tend to influence more and more individuals towards vegetarian diets. This paper proposes a methodology to model a network of arguments around vegetarian diets by an abstract argumentation approach. Each argument, formalized by a node is connected with other arguments by arrows formalizing relationships between arguments. Thanks to this methodology we were able to formalize an argument network about vegetarian diets and identify the foremost importance of health argument compared with ethical or other type of arguments. This methodology also identified key arguments due to their high centrality in being challenged or challenging other arguments. These first results from this argument network construction suggest that any controversy surrounding vegetarian diets may polarize around such high centrality arguments about health. Even though ethical arguments appear of low importance in our network, the key issue of the necessity of animal products for human health may be essential for ethical choices towards vegetarian diets.

INTRODUCTION

The first nutrition transition involved the rise of sugar, fat, meat and processed products in human diets [START_REF] Popkin | Nutritional Patterns and Transitions[END_REF]) and is the dominant nutritional model today. [START_REF] Vranken | Curbing global meat consumption: Emerging evidence of a second nutrition transition[END_REF] identified a second nutrition transition happening in the most developed countries where meat consumption is currently curbing down. Transition towards reducing meat consumption covers a wide variety of practices ranging from occasional vegetarianism to veganism (also called "strict vegetarian") (Bearsworth & Kiel 1991). Rationale for such transition mainly implies ethical and health concerns [START_REF] Jabs | Model of the process of adopting vegetarian diets: Health vegetarians and ethical vegetarians[END_REF]) but environmental impact of meat consumption is also stressed on a lower degree [START_REF] Ruby | Vegetarianism. A blossoming field of study[END_REF]. MacDonald (2000) conducted individual interviews with vegans and found that their nutritional transition depended on a catalytic experience orienting individual towards information acquisition and ultimately conducting to a decision for change. However, the information acquisition leading to decision is not precisely known among vegetarians. In this paper we present a methodology to explore main arguments and their relations between them that transitioning individuals may face during this process.

METHOD

General approach

In order to model arguments involved with vegetarian transitions we used an abstract argumentation approach (Dung 1994[START_REF] Rahwan | Argumentation in Artificial Intelligence[END_REF][START_REF] Thomopoulos | Multidimensional Analysis Through Argumentation[END_REF]. We extracted arguments in favor or not of reducing animal product consumption. Our sources of arguments are newspapers, grey literature and top ten google research ("vegetarian diet"; "vegan diet"; "vegetalism argument"). The latter inquiry added to the pool popular scientific papers, webmedia articles and blog posts. We read thoroughly each source and extracted all arguments as expressed by their author. For each argument we attributed a criterion ("Nutritional"; "Economic"; "Environmental"; "Anthropological"; "Ethical"; "Health" or "Social") and noted the source expressing this argument ("Journalist"; "Scientist", "Philosopher"; "Blogger", etc.). We consequently obtained 114 arguments.

The argumentation formalism

Let us recall that an argumentation system is usually represented as an oriented graph where nodes are Comment citer ce document : Salliou, N., Thomopoulos, R. (2018). Modelling multicriteria argument networks about reduced meat consumption . Presented at FOODSIM'2018, Ghent, BEL (2018-04-08 -2018-04-12).

arguments and edges are attack relations between arguments (Figure 1). (1995), an argument and the attack relation are abstract and can be instantiated and defined in different ways in different contexts (Walton, 2009).

Dung himself stated: "an argument is an abstract entity whose role is solely determined by its relations to other arguments. No special attention is paid to the internal structure of the arguments". For example, an argument can be a set of statements composed of a conclusion and at least one premise, linked by an inference or a logical relation. Attacking an argument can be achieved in different ways: 1) by raising doubts about its acceptability through critical questions; 2) by questioning its premises; or 3) by putting forward that the premises are not relevant to the conclusion or 4) by presenting an argument with an opposing conclusion. In all these cases an attack relation is said to exist (e.g Figure 2). Even though Dung's framework is theoretically sound it is not straightforward to apply in real life situations. Indeed, one of the initial difficulty is to how to define an argument in order to properly reflect stakeholders' statements in a debate. Unfortunately, there is still no general model that can be used to formalize a natural argument (i.e. an argument stated by a stakeholder during a discussion in natural language) and input in an abstract argumentation framework in a real decision-making context. Quoting [START_REF] Baroni | Semantics of Abstract Argument Systems[END_REF]: « While the word 'argument' may recall several intuitive meanings, like the ones of 'line of reasoning leading from some premise to a conclusion' or of 'utterance in a dispute', abstract argument systems are not (even implicitly or indirectly) bound to any of them: an abstract argument is not assumed to have any specific structure but, roughly speaking, an argument is anything that may attack or be attacked by another argument». Indeed, the structure of an abstract argument does not correspond to the intuitive understanding of what an argument is. Moreover, the notion of "attack between arguments" does not have a natural and direct correspondence to practical expressions used by stakeholders when debating. Moreover, representing arguments as an oriented graph can be a difficult task for stakeholders: when the number of arguments and/or attacks is large, the graph becomes illegible and difficult to interpret by stakeholders.

In our project, we needed to find a practical way of defining arguments that are used in the process of decision making. In such a context arguments can be intuitively thought of as being statements to support, contradict, or explain opinions or decisions [START_REF] Amgoud | Using arguments for making and explaining decisions[END_REF]. More precisely, in decisional argumentation frameworks [START_REF] Ouerdane | Argumentation Theory and Decision Aiding[END_REF], the argument definition is enriched with additional features, namely the decision (also referred to as 'action', 'option' or 'alternative') and the goal (also referred to as 'target'). In other studies arguments are also associated with specific actors. An application of a decision-oriented argumentation framework to a real-life problem concerning food policy can be found in [START_REF] Bourguet | An artificial intelligencebased approach to deal with argumentation applied to food quality and public health policy[END_REF], where a recommendation regarding the provision of wholegrain bread was analyzed a posteriori. In this case, each argument is associated with the action it supports. Based on the above rationale, we chose to specify an argument as a tuple composed of an identifier, a type, an explanation, a criterion, an option and a sub-option. -T is the type of the argument (with values in favour of, denoted by '+', or against, denoted by '-', the vegetarian option); -S is the statement of the argument, i.e. its conclusion; -R is the rationale underlying the argument, i.e. its hypothesis; -C is the criterion which the argument relies on; -A is the actor who proposes the argument; -Is is the information source containing the argument; -Ts is the type of source the argument comes from.

For any argument a, we denote by I(a), T(a), S(a), R(a), C(a), A(a), Is(a), Ts(a) respectively the identifier, the type, the statement, the rationale, the criterion, the actor, the information source and the information type of argument a.

As an illustration, Table 1 displays a sample of the set of arguments considered in our case study. [START_REF] Besnard | Elements of argumentation[END_REF]. The intuition of these attack relations is either to counter the premise of the opposing argument ('undercut'), the conclusion ('rebut') or to attack the logical steps that allowed the inference between the argument's premise and conclusion (undermine). In abstract argumentation the set of attacks is simply considered as provided a priori. Another possibility that can be considered is to enhance the argumentation framework with a set of preferences, expressed for instance as weights representing uncertainty. In our project we needed to choose a practical way to define the attack relation. Considering the reality of stakeholders' debates and our model to formalize arguments, we chose to model the attack relation in the following way. Attacking an argument a is achieved by: 1) explicitly raising doubts about its acceptability by expressing a counter-argument citing a or the information source containing a; 2) implicitly raising doubts about its acceptability by expressing a counter-argument contradicting a through undercut, rebut or undermine. Formally, we consider the following attack relation: Let a and b be two arguments. We say that a attacks b if and only if the following two conditions are satisfied:

1) T(a) ≠ T(b); 2) {R(a), S(a)} → not {R(b), S(b)}.
The first condition expresses that arguments a and b are one in favour and the other against the vegetarian option. The second condition expresses the inconsistence of a and b.

Modelling arguments and attacks

Each argument was first formalized by an identification number, whether is in favor or not of meat reduction diets (+/-), its main statement and rationale such as: "Vegan diet is related with B12 vitamin deficiency" (Statement) as "plants do not contain B12 vitamin" (Rationale). Other information (Actor, Information source & Type of source) characterize the origin of the argument. Based on this first step we then formalized attacks between them. An attack occurs when an argument is contradicting another one. For example the argument "1" quoted above is contradicted by the following argument "28 -Properly planned vegetarian or vegan diets fits all stage of life" as "Nutrient needs are satisfied and growth is normal". When these arguments are formalized graphically each one is represented as a node and an attack is a vertex connecting both arguments, the arrow pointing the direction of the attack. In our case study, we identified 155 attacks connecting 55 arguments among our total of 114.

Graphical representation of the argument network

In order to make a graphical representation of the argument network we used the visualization program Yed Graph Editor (version 3.17.1). We choose to represent only arguments which are connected with at least one attack. Each argument node received a specific color according to the source expressing the arguments. For visualization purposes, we grouped together identical arguments when repeated and coming from the same source (Figure 3).

MAIN LESSONS AND PERSPECTIVES

Our argument network structure reveals in particular two main elements. First, one can notice that arguments about Health are by far the majority of arguments identified. They represent 47% of all 114 arguments identified and 63% of arguments involved in at least one attack. As a matter of comparison ethical arguments represent only 3% of all arguments identified. Second, some key arguments are emerging due to their centrality. Two arguments are involved in more than 3 attacks. The first argument, grouped under identification numbers 28, 57, 108 and 111 (the black node in Figure 3), refers to a scientific paper from the American Dietetic Association stating that "Properly planned vegetarian or vegan diets fits all stage of life" [START_REF] Craig | Position of the American Dietetic Association: Vegetarian Diets[END_REF]. The second argument, identification number 71 and 72 grouped together, is a journalist statement that "No study is favorable to the vegan diet". Both arguments would probably be key arguments in potential controversy about vegetarian diets due to their generality.

The major importance of health issues surrounding vegetarian diets are in line with findings in Ruby's (2012) review of vegetarian studies. On the opposite, the importance of ethical arguments which was stressed by [START_REF] Ruby | Vegetarianism. A blossoming field of study[END_REF] did not appear in such modelling. This could be explained by the more complex nature of ethical arguments as well as our choice of research keywords in Google which focused on diets. However, from an ethical perspective it seems that the health issue (whether or not vegetarian diets are healthy) is actually central as animal rights may be defended from the baseline of animal products not being necessary for human health [START_REF] Francione | Eat Like You Care: An Examination of the Morality of Eating Animals[END_REF].

In this research we built the network and proposed a structural analysis. Abstract argumentation opens further analysis and in particular the rejection of attacked arguments without any argument to defend them. Such analysis allow for new indicators such a polemical indicators based on rejected argument ratios [START_REF] Thomopoulos | Multidimensional Analysis Through Argumentation[END_REF]) which can better identify potential controversies. Following the theoretical approach of Xie et al. ( 2011) such argument network could also be used together with agent-based modelling to explore emergent establishment of new social norms on the concrete case of vegetarianisms. Such model could help to understand the conditions under which such arguments could spread in a population and favor vegetarian diets normalization.

CONCLUSION

The method presented in this paper formalizes arguments and attacks around vegetarian diets using an abstract argumentation approach. The argument network revealed the foremost importance of health issues surrounding vegetarian diets. The centrality of some argument of the network allows for identification of potential key arguments and/or controversies. The importance of health arguments in relation with ethical argument should be further researched.

Figure 1 :

 1 Figure 1: General graphical representation of an argumentation system

Figure 2 :

 2 Figure 2: Examples of four types of attacks. 1: Raising doubts; 2: Questioning premises; 3: Irrelevant premises; 4: Opposing conclusions

  Formally: An argument is a tuple a = (I;T;S;R;C;A;Is;Ts) where: -I is the identifier of the argument; Comment citer ce document : Salliou, N., Thomopoulos, R. (2018). Modelling multicriteria argument networks about reduced meat consumption . Presented at FOODSIM'2018, Ghent, BEL (2018-04-08 -2018-04-12).

  Comment citer ce document : Salliou, N., Thomopoulos, R. (2018). Modelling multicriteria argument networks about reduced meat consumption . Presented at FOODSIM'2018, Ghent, BEL (2018-04-08 -2018-04-12).

Figure 3 :

 3 Figure 3: Graphical Representation of Arguments and Attacks about Reduced Meat Consumption. (Each number corresponds to one argument express by one source. Each source is represented by one node color except for similar arguments which have been group together. Arguments have been grouped by category.)

Table 1 :

 1 Sample of Arguments Tuples about Reduced Meat Consumption (I: Identification; T: Type; Is : Information source; Ts: Type of source)

	I T	Statement	Rationale	Criterion	Actor	Is	Ts
	1 -	Vegan diet is deficient in B12 vitamin	Vegetal proteins do not contain B12 vitamin	Nutritional	Jounalist	Canard -Juillet 2017 Enchainé -144	Newspaper
	15 -	Plant proteins trigger allergies	Plant-based food are more regularly allergic	Nutritional	Innovation cluster	Valorial	Powerpoint
	23 +	Vegetarian diet is good for health	Diabetes, cancer and coronary risks are reduced	Health	Scientists	Tilman & Clark 2014	Scientific paper
	28 +	Properly planned vegan or vegetarian diets fits all stages of the life cycle	Nutrient needs are satisfied and growth is normal	Health	American Dietetic Association	Craig et al. 2009	Scientific paper
	43 +	Vegan diet improves the rheumatoid arthritis activity	A diet-induced faecal flora change was observed	Health	Scientists	Peltonen et al. 1997	Scientific paper
	55 +	Eating meat is not in human's nature	It was sometimes necessary in the past to eat meat, not nowadays	Anthropological	Blogger pro-vegan	Blog -Eleusis et Megara	Blog post
	56 +	Stop eating animals does not mean animal extinction	Deforestation for the extinctions; cultivation of animal feed provokes species	Environmental	Blogger pro-vegan	Blog -Eleusis et Megara	Blog post
	59 +	Animals suffer when eaten, not plants	A nervous system is needed to suffer, which plants do not have.	Ethical	Blogger pro-vegan	Blog -Eleusis et Megara	Blog post
	71 -	No study is favorable to the vegan diet	One good quality study show that Atkins diet is better that Ornish diet	Health	Journalist	Signs Of The Times	Internet article
	77 -	No health reason justifies to avoid animal products	Human body is adapted to eat animal products for millions of years	Health	Journalist	Signs Of The Times	Internet article
	Now, let us consider the attack relation. In structured
	argumentation (i.e. logic based argumentation
	frameworks where arguments are obtained as
	instantiations over an inconsistent knowledge base)
	three kinds of attacks have been defined: undercut,
	rebut and undermine

BIOGRAPHIES


Olivier Turc

Vincent Oury

Yves Gibon

Duyên Prodhomme

Francois Tardieu

Yield maintenance under drought: expansive growth and hydraulics also matter in reproductive organs

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

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  UMR 759 Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux (LEPSE), INRA Montpellier, France 2 UMR 1332 Biologie du Fruit et Pathologie (BFP), INRA Bordeaux, France 2 Perform realistic water deficits and abortion rates in controlled platforms Four maize hybrids were grown in pots and subjected to different levels of soil water availability in greenhouse and growth chamber experiments (Phenodyn phenotyping platform). Soil water status was managed by weighing pots and adjusting water supply to the target soil water content. Three treatments were applied from tassel emergence (TE) to 7d after first silk emergence (SE), namely well watered (WW), mild deficit (WD1) and moderate deficit (WD2), with soil water potential above -0.10 MPa, around -0.25 MPa and around -0.50 MPa respectively (Fig.1A). Their impacts on photosynthesis (Fig.1C), transpiration (Fig.1B) and seed set (Fig.2) were similar to those commonly observed in drought prone fields.1 Summary Yield maintenance under drought in maize (Zea mays) is associated with flowering synchrony which requires the rapid extension of styles and stigma (silks) to be accessible for pollen. We show here that the control of grain set under moderate water deficits similar to those in the field results from a developmental process linked to the timing of silk growth, itself related to expansive growth and hydraulics processes, in opposition to the common view that abortion is linked to the sugar metabolism in ovaries.6 PerspectivesThese results confer a pivotal role to hydraulic controls of expansive growth processes in grain yield elaboration upon changes in environmental conditions. They have large consequences in plant breeding, modelling and phenotyping. Genotypes largely differ for the sensitivity of silk elongation rate to xylem water potential (Fig.12), and sensitivities of silk and leaf growth were correlated (Fig.13). This opens the way for genetic studies of the traits, genes and physiological processes controlling grain set under non-optimal climatic scenarios. These sensitivities and their genetic variability have to be included in the formalisms of crop models simulating yield in maize (e.g. APSIM model). An original method for phenotyping silk growth is currently developed by our group (companion poster IDT6-014). Oury V, Caldeira CF, Prodhomme D, Pichon J-P, Gibon Y, Tardieu F, Turc O. 2016. Is change in ovary carbon status a cause or a consequence of maize ovary abortion in water deficit during flowering? Plant Physiology 171: 997-1008. Oury V, Tardieu F, Turc O. 2016. Ovary apical abortion under water deficit is caused by changes in sequential development of ovaries and in silk growth rate in maize. Plant Physiology 171: 986-996. Turc O, Bouteillé M, Fuad-Hassan A, Welcker C, Tardieu F. 2016. The growth of vegetative and reproductive structures (leaves and silks) respond similarly to hydraulic cues in maize. New Phytologist 212: 377-388. Carbon metabolism in ovaries was still unaffected at silk emergence Changes in concentration and amount of sugars (Fig. 10), in activities of enzymes (Fig. 10) and in transcript levels (Fig. 11) of genes of sugar metabolism occurred 5 d after silk emergence in apical ovaries that eventually aborted, i. e. after the switch to abortion of these ovaries. Hence, we propose that, under moderate water deficits corresponding to most European drought scenarios, changes in ovary carbon metabolism during flowering time are a consequence rather than a cause of the beginning of ovary abortion. Silk growth is controlled by xylem water potentialAnalyses of transcripts and metabolites indicate that the first molecular events induced by drought occur at first silk emergence (SE), in silks rather than in ovaries, and involve genes affecting expansive growth rather than sugar metabolism (Fig.6). Silk elongation rate was measured using displacement transducers (Fig.7). Time courses revealed that silk elongation rate closely followed changes in soil water status and evaporative demand, with day-night alternations similar to those in leaves (Fig.8, Fig.9). Day-night alternations were steeper with high than low plant transpiration rate, manipulated via evaporative demand or by covering part of leaf area (Fig.9). Half times of changes in silk elongation rate upon changes in evaporative demand or soil water status were of 10-30 minutes (Fig.8), similar to those in leaves, suggesting a common hydraulic control of expansive growth in both vegetative and reproductive structures.

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A Valldecabres

J A A Pires

N Silva-Del-Río

Keywords: fatty liver, cytology, histology

Fatty liver (FL) is a common condition affecting dairy cows during the peripartum period, with no diagnostic test that is accurate, fast, and low cost. FL can be determined by TG extraction, histopathology or flotation of liver biopsies from live animals. However, these methods are invasive, and at higher risk of hemorrhages, infection and adhesions. Cytology for detection of FL in cattle has not been extensively evaluated. It is feasible in clinical practice, being minimally invasive and inexpensive, and having a rapid turnaround time compared with biopsy. The objective was to estimate the sensitivity (Se) and specificity (Sp) of needle aspiration cytology and histopathology for FL using TG concentrations as the gold standard. Liver samples were harvested from a slaughterhouse in WI, USA. Livers were visually inspected for gross evidence of fat accumulation and classified as follow. (1): Normal-homogeneous maroon color (n = 20), (2): Moderate-moderate yellow-pale color (n = 20) and (3): Severe-more extreme yellow color (n = 20). Biopsies and needle aspiration were carried out from the parietal upper portion of the caudate lobe. Two samples of liver tissue were harvested with a 16 g x 15 cm biopsy needle for histological and TG concentration assessment. A third sample was harvested for cytology using an 18 g × 3.81 cm needle. The content of the needle was transferred to a glass slide, spread and air-dried. TG were assessed by a kit based on colorimetry/fluorimetry. Concentrations <2% were considered normal. Histological and cytological evaluation was blind to the visual classification and conducted by 2 pathologists. Se, Sp, and area under the receiver-operating curve [ROC] were calculated. For cytology, Se and Sp were 73% (95% CI 55.9-86.2) and 85% (95% CI 62.1-96.8), respectively. The area under ROC was 0.79 (95% CI 0.68-0.89). For histopathology, Se and Sp were 45.9% (95% CI 29.5-63.1) and 100% (95% CI 83.2-100), respectively. The area under ROC was 0.73 (95% CI 0.64-0.81). This data suggests that cytology may be a viable less invasive tool for detecting FL in dairy cattle.

The objective was to evaluate factors associated with calcemic status at calving on 527 multiparous Jersey cows from 2 commercial dairies. Study variables included: lactation number (Lact; continuous, or 2, 3, ≥ 4); previous lactation 305-d mature equivalent milk production (Pr305ME) and somatic cell count (PrSCC); calving body condition score (BCS; ≤ 2.5, 2.75, ≥ 3) and locomotion score (LS; ≤ 2, 3, ≥ 4); calf number, sex, and stillbirth; and dry period length (dDry). Blood samples for serum Ca analysis were collected from the coccygeal vessels 3 h 14 min (±2 h 04 min) after calving. Previous lactation information and calving outcomes were obtained from DairyComp305 herd records. Based on serum Ca concentration at calving cows were classified as hypocalcemic (SHC; Ca ≤8.5 mg/dL; n = 347) and normocalcemic (NC; Ca >8.5 mg/dL; n = 180). Associations among variables were studied using spearman rank correlations and mixed models for continuous, and chi-squared and exact fisher tests for categorical data (CORR, MIXED, GLIMMIX and FREQ procedures of SAS). A significant positive correlation was observed between Lact and BCS, and both were negatively correlated with serum Ca concentration at calving. Cows with SHC had greater (P < 0.001) Lact (3.6 vs. 2.7), frequency of Lact ≥4 (40.4 vs. 14.4%),dDry (68.8 vs. 64.6 d),and BCS (43.4 vs. 58.2%,31.2 vs. 27.7% and 25.4 vs. 14.1% for BCS ≤2.5, 2.75 and ≥3, respectively; P = 0.02[N1]) than NC cows. Twinning rate was higher for SHC than NC (5.8 vs.1.1%; P = 0.01). The frequency of male calves (n = 98) was higher for SHC than NC cows (22.4 vs. 14.0%, P = 0.02), however, sexed semen was selectively used on both dairies and these results may derive from herd reproductive management. There was no association of Pr305ME, PrSCC, LS at calving or frequency of stillbirth with calcemic status. These complex associations among SHC, Lact, BCS, dDry, twinning and calf sex, could be used for the decision-making concerning prophylactic SHC treatment at calving.

Key Words: Jersey cow, hypocalcemia

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Effects of chloride and sulfate-based diets fed to grazing prepartum dairy cows on postpartum plasma calcium. P. Melendez* 1 , V. Zaror 2 , P. Gaul 2 , S. Poock 1 , and J. Goff 3 , 1 College of Veterinary Medicine, University of Missouri, Columbia, MO, 2 Tribute Dairy, Benton, MO, 3 College of Veterinary Medicne, Iowa State University, Ames, IA.

Hypocalcemia is a common metabolic disorder affecting dairy cows during the postpartum period. Lowering dietary cation-anion difference (DCAD) by feeding supplemental chloride or sulfate has been shown to reduce the incidence of hypocalcemia. Different sources of anions have not been extensively compared under practical conditions. The aim of this study was to compare the effect of chloride (Cl) (SoyChlor; commercial chloride supplement) and sulfate (S) (magnesium sulfate) fed to grazing prepartum cows on postpartum plasma Ca. The study was conducted in southeast Missouri, USA in the fall of 2016. Breeds consisted of 20% Holstein, 20% Jersey and 60% crossbred Jersey × Holstein. Cows had been synchronized for breeding such that approximately 600 cows were due to calve in a short period of time. At 30 d before expected parturition, 2 groups of 200 cows each were moved into paddocks where they were fed each day a partial mixed ration (PMR) containing the anionic supplements. Cows had free access to pasture. The PMR would constitute half of the daily DMI. Estimated DCAD for the 2 diets was -25 mEq/kg DM and -26 mEq/kg DM for Cl and S, respectively. Urine samples were collected each week prepartum and checked for pH. Average pre-partum urine pH was 7.71 ± 0.12 and 7.81 ± 0.10 (P = 0.06) for Cl and S, respectively. At calving, 42 cows per group were matched by breed and parity (primiparous, multiparous), and their blood was sampled on d 1, 2, 3, and 7 postpartum. Plasma total Ca was determined by atomic absorption spectroscopy. Data for blood Ca concentration were analyzed by developing a mixed model ANOVA for repeated measures and the best covarinace structure to fit the model. It is concluded that cows fed a TMR based on chloride had a higher calcium concentration at d 1 than cows fed sulfur as a source of anions.

J. Dairy Sci. Vol. 100, Suppl. 2