Devenir des jeunes ruminants laitiers : comment concilier élevage et attentes sociétales.

Dans les conditions naturelles, les jeunes ruminants développent un lien privilégié avec leur mère dans les heures qui suivent la naissance, lien qui perdure bien au-delà de l’allaitement. Or, sur les 5,5 millions de jeunes ruminants (veaux, chevreaux et agneaux) qui naissent chaque année en France dans des élevages laitiers, la grande majorité sont séparés de leur mère à la naissance et allaités « artificiellement » au seau. La séparation mère-jeune précoce interpelle les citoyens et certains éleveurs quant au respect du bien-être de l’animal. L’allaitement artificiel des femelles de renouvellement jusqu’au sevrage permet d’assurer, à un coût maîtrisé, un développement mammaire optimal et un bon potentiel laitier. Cependant, l’allaitement par les mères ou par des nourrices se développe, principalement en élevage bovin. Ce type d’allaitement entraîne généralement des quantités de lait commercialisables moindres, mais la croissance, la santé et le bien-être des veaux sont améliorés. Des questions se posent aussi sur le devenir des jeunes, mâles pour l’essentiel, non conservés pour le renouvellement du troupeau. Ceux-ci quittent généralement l’élevage quelques semaines après la naissance pour être engraissés dans des ateliers spécialisés, voire exportés. Là aussi, afin de répondre aux nouvelles attentes des consommateurs et pallier le faible intérêt économique de ces débouchés, éleveurs et filières recherchent des solutions alternatives telles que l’engraissement à la ferme, de nouveaux modes d’élevage ou de nouveaux débouchés. Ces pratiques alternatives – allaitement naturel ou engraissement sur place des jeunes mâles – pourraient se développer grâce à une identification de leurs produits (lait, viande) et au consentement du consommateur à les payer plus cher que des produits standards

Final report for the CORE Organic Cofund funded project “Promoting young stock and cow health and welfare by natural feeding systems- ProYoungStock”

The ProYoungStock project aimed to improve the lives of young cattle and conducted research in 8 European countries: Austria (AT), France (FR), Germany (DE), Italy (IT), Poland (PL), Slovenia (SI), Sweden (SE), and Switzerland (CH). Interviews with 104 dairy farmers in AT, FR, DE, IT, SE, CH showed that many diverse cow-calf contact systems (CCC) are practised in Europe. Better animal welfare and reduced labour were perceived as benefits of CCC, while stress when cow and calf are separated, lower amounts of saleable milk, and building constraints were seen as challenges. Trials in different countries with either focus on feeding strategies (e. g. more milk, use of supplements as linseeds or tannins, silage vs. no silage) or different rearing systems (i.e. 7 different CCC systems compared to control without CCC) revealed the following results concerning: Calf growth: Calves benefited from increased milk levels (10-12 l/day compared to 6-8 l/day) (DE, AT), from permanent CCC compared to control (PL), from CCC when fed by dams before morning milking and with 6 h/day access to dams until weaning. But there was no impact when CCC of 6 h/day was carried out for only 3 weeks (FR) as well as when CCC was restricted to 2 x 30 min/d until 16 weeks of life. These results show that CCC alone does not necessarily promote calf growth! Behaviour disorders and welfare: Main behaviour disorders in calves are sucking each other (cross sucking) or manipulating any objects with their mouth. We observed less cross sucking in calves with permanent foster cow contact and with 2x30 min/d contact to the dam (CH, PL). Calves with permanent foster cow contact also manipulated less objects compared to bucket fed calves (PL). Increased milk feeding (DE) and limited access to the dam 2x30 min/d (CH) however, did not reduce those manipulations. CCC calves had lower hair cortisol contents (less stress) before weaning, but after weaning they vocalized earlier and longer (indicating stress) than control calves. (FR). Calf health: Immunoglobulin-levels in calves’ serum from mothers supplemented with linseeds 30 days before and after calving were higher than in calves from control mothers (PL). However, calf health in 5 variations of CCC systems did not differ compared to control systems (PL, FR, SE, and CH). We found no relevant effect of CCC on the gut microbiota development in calves, nor on the passive immune transfer from cows to neonatal calves (FR), nor on a further build-up of the active immune defence during the pre-weaning period (FR, CH). Cow health: There were no differences in somatic cell count (udder health indicator) and cows’ health events in 3 variations of CCC-systems compared to control (FR, SE). CCC practices did not influence contents of immunoglobulin G and lactoferrin in cow’s milk (FR, CH). Reproductive performance of multiparous cows did not differ between CCC and control, but was improved in primiparous cows in CCC systems (FR, CH, and SE). Extensively reared animals showed lower disease incidences than animals that did not have this experience (AT, FR), but there was no influence of extensive rearing on calving interval (AT, FR, SI). There was no difference between farms with or without silage feeding regarding reproduction (AT, DE, SI), but a negative effect of silage free rearing on udder health was found (AT, DE). Milk contents: In CCC-systems we found higher protein contents and lower fat contents (except when calves suckled before milking) than in milk from control cows (FR). Linseed-feeding before calving increased unsaturated fatty acids in colostrum (PL). Milk and fat yields were higher with silage feeding than without in AT, DE, FR, but lower in SI. Feeding tannin extracts to cows during the dry season (hay feeding) revealed lower urea contents, a better fatty acid profile and a higher antioxidant capacity in milk and cheese (IT). Meat quality: pH of meat 24 h after slaughter was lower in calves with foster cow rearing, but the main fatty acids did not differ between calves from CCC systems and control (PL, CH). Economic impact of CCC: CCC systems produced 21% to 43% less saleable milk compared to control. The best compromise between milk yield and calf growth was reached with 6 – 9 h CCC between morning and evening milking until weaning (SE, FR). Ecological impact of tannin feeding: In vitro blended tannin extracts reduced ruminal protein degradation and ammonia and methane emissions; especially when hay feeding was simulated (IT). As there is no one-fits all solution (but there are many pieces of a puzzle), the large variation in management led us to organise many workshops for farmers, so they could exchange on the diverse possibilities of CCC and find out which is the best one for their farm. Those workshops are great to introduce CCC-systems because farmers advise farmers. More information for farmers and the scientific community is available at www.proyoungstock.net

M19 Modulates Skeletal Muscle Differentiation and Insulin Secretion in Pancreatic β-Cells through Modulation of Respiratory Chain Activity

Mitochondrial dysfunction due to nuclear or mitochondrial DNA alterations contributes to multiple diseases such as metabolic myopathies, neurodegenerative disorders, diabetes and cancer. Nevertheless, to date, only half of the estimated 1,500 mitochondrial proteins has been identified, and the function of most of these proteins remains to be determined. Here, we characterize the function of M19, a novel mitochondrial nucleoid protein, in muscle and pancreatic β-cells. We have identified a 13-long amino acid sequence located at the N-terminus of M19 that targets the protein to mitochondria. Furthermore, using RNA interference and over-expression strategies, we demonstrate that M19 modulates mitochondrial oxygen consumption and ATP production, and could therefore regulate the respiratory chain activity. In an effort to determine whether M19 could play a role in the regulation of various cell activities, we show that this nucleoid protein, probably through its modulation of mitochondrial ATP production, acts on late muscle differentiation in myogenic C2C12 cells, and plays a permissive role on insulin secretion under basal glucose conditions in INS-1 pancreatic β-cells. Our results are therefore establishing a functional link between a mitochondrial nucleoid protein and the modulation of respiratory chain activities leading to the regulation of major cellular processes such as myogenesis and insulin secretion

The French nutrition system for ruminants

International audienc

Once-daily milking of dairy cows: a review of recent French experiments

Once-daily milking (ODM) implemented in the declining phase of lactation for up to at least 10 weeks reduced milk yield by 20–30%, according to the trial, from the first day. Milk loss (%) exhibited a high between-cow variability and was unrelated to the milk yield (kg) of the cows. When twice-daily milking (TDM) was resumed, milk yield recovered completely following implementation of ODM for a few days, but reached only about 90% of the yield of TDM cows following implementation of ODM for 8–10 weeks. When implemented from calving, ODM had a progressively higher negative impact (a decrease of between 30 and 50%), which was more pronounced in primiparous cows than in multiparous cows. The residual loss (%), once TDM resumed, was generally higher than in the declining phase. When ODM was implemented during three successive lactations, there was no between-lactation effect. ODM increased fat and protein content in milk and decreased lactose content by an average 2.8, 1.5 and 1.5 g·L–1, respectively. The casein/protein ratio was reduced (by 1.8% on average). Resumption of twice-daily milking cancelled these modifications within a few days. Protease activity in milk tended to increase, whereas lipase activity tended to decrease with ODM. Free fatty acid content was reduced significantly with ODM. Implementation of ODM did not significantly modify feed intake of the cows in the short term (up to 6–8 weeks), but tended to decrease it thereafter. The quality of cheese manufactured from TDM or ODM milks were similar. ODM implementation led to an improved nutritional status of the cows, as appreciated by changes of live weight, body condition score, or calculated energy balance. It also improved reproduction parameters. The cows adapted quickly to ODM (within a few days). ODM increased the somatic cell count in milk without impact on mastitis infection incidence in the short term. When implemented throughout lactation during which cows were partly in barn conditions, ODM increased mastitis infection incidence in 2 out of 3 trials.La traite une fois par jour des vaches laitières : revue des récents essais français. Utilisée pendant la phase descendante de la lactation pour des durées allant jusqu'à 10 semaines, la traite une fois par jour (monotraite) a réduit la quantité de lait produite de 20 à 30 % selon les essais, dès le 1er jour. Cette réduction (%) a présenté une variation individuelle élevée mais indépendante du niveau de production laitière des vaches. Quand la traite deux fois par jour (traite bi-quotidienne) a été reprise, les vaches ont complètement recouvré leur production de lait lorsque la monotraite n'avait duré que quelques jours, mais elles n'en ont recouvré que 90 % après une monotraite de 8 à 10 semaines. Mise en œuvre dès le début de la lactation, la monotraite a eu un impact négatif progressif, plus élevé que pendant la phase descendante (diminution de 30 à 50 %), et plus prononcé chez les vaches primipares que chez les multipares. Quand la monotraite a été utilisée de façon continue pendant les 3 premières lactations, elle n'a pas eu d'effet cumulatif d'une lactation à la suivante. La monotraite a accru les teneurs du lait en matières grasses et en protéines, et elle a diminué la teneur en lactose, de respectivement 2,8 g·L–1, 1,5 g·L–1 et 1,5 g·L–1. Le rapport caséines/protéines a été réduit de 1,8 point p. 100 en moyenne. La reprise de la traite bi-quotidienne a annulé ces modifications en quelques jours. L'activité protéasique a eu tendance à augmenter avec la monotraite alors que l'activité de la lipoprotéine lipase a eu tendance à diminuer. La teneur du lait en acides gras libres a été significativement réduite par la monotraite. La mise en œuvre de la monotraite n'a pas modifié significativement les quantités d'aliments ingérées par les vaches, à court terme (6–8 semaines), mais elle a eu tendance à les accroître à plus long terme. Les caractéristiques du fromage fabriqué avec du lait de vaches soumises à la monotraite ou à la traite bi-quotidienne ont été semblables. La monotraite a amélioré l'état nutritionnel des vaches, apprécié par le changement de poids vif, la note d'état corporel ou le bilan énergétique calculé. Elle a aussi amélioré les paramètres de la reproduction. Les vaches se sont habituées en quelques jours à la monotraite. Celle-ci a accru le nombre de cellules dans le lait (nombre par mL) sans impact, à court terme, sur l'incidence de mammites. Quand la monotraite a été utilisée pendant toute la lactation, dont une partie se déroulait en étable, elle a accru l'incidence des mammites dans deux des trois essais réalisés

Performances des vaches laitières et qualité du lait lors de la monotraite et après retour à 2 traites par jour, en fonction de la durée de cette pratique et du stade de lactation des animaux

International audienc

Effet de la monotraite des vaches laitières sur leur production, selon le niveau de distribution d’aliments concentrés

National audienceThis trial compared the milk production of cows 1/ while they were milked twice or once daily and were fed 2 levels of concentrate (normal or low [normal – 3 kg]) or three levels (normal, low or very low [normal – 6 kg]) respectively (6 weeks); 2/ once they were again milked twice daily and fed according to the feeding recommendations (5 weeks). Five groups of 11 cows in the declining phase of lactation were involved. The effects of once daily milking (ODM) and of the reduction of concentrate were those commonly observed in the literature. Milking frequency and level of concentrate did not interact for any of the measured parameters. This suggests that their modes of operation were different. The very low level of concentrate during ODM seemed to make the recovery of milk yield, once the twice daily milking and normal concentrate feeding were resumed, less complete or later.Cet essai compare la production laitière de vaches : 1- pendant qu’elles sont traites 2 fois ou 1 fois par jour et reçoivent respectivement 2 niveaux (normal ou bas [normal – 3 kg/j]) ou 3 niveaux (normal, bas, très bas [normal – 6 kg/j]) d’aliment concentré (6 semaines) ; 2- une fois qu’elles sont de nouveau toutes traites 2 fois par jour et alimentées selon les recommandations de l’INRA (5 semaines). L’essai a été conduit avec 5 lots de 11 vaches en début de phase descendante de la lactation. Les effets de la monotraite et de la réduction de l’apport de concentré ont été ceux classiquement rapportés dans la bibliographie, sauf en ce qui concerne la teneur en matières grasses qui tend à diminuer quand l’apport de concentré est réduit. Pour aucun des paramètres mesurés les 2 facteurs étudiés n’ont interagi. La réduction de l’apport de concentré à des vaches en monotraite, généralement suralimentées, diminue leur production d’une quantité semblable à celle observée chez des vaches en traite biquotidienne. La forte restriction du niveau d’alimentation pendant la monotraite semble rendre moins complet, ou plus tardif, le recouvrement de la production laitière une fois la traite biquotidienne et le niveau normal de distribution de concentré remis en œuvre

La monotraite ne modifie pas la composition en acides gras du lait, chez la vache en bilan énergétique équilibré

National audienc

The analysis of a co-design process to develop an eco-citizen dairy cattle farming system experiment

Session 45. Transformation of livestock practices in response to society’s expectations on animal welfare, market demand for animal products and environmental issuesInternational audienc