Repeatability of traits for characterizing feed intake patterns in dairy goats: a basis for phenotyping in the precision farming context

International audienceIn ruminants, feeding behaviour variables are parameters involved in feed efficiency that show variation among individuals. This study aimed to evaluate during the first two production cycles in ruminants the repeatability of feed intake pattern, which is an important aspect of feeding behaviour. Thirty-five dairy goats from Alpine or Saanen breeds were housed in individual pens at four periods (end of first gestation, middle of first and second lactations and middle of second gestation which is also the end of first lactation) and fed a total mixed ration (TMR) ad libitum. Individual cumulative dry matter intake (DMI) was automatically measured every 2 min during the last 4 days of each period. Feed intake pattern was characterized by several measures related to the quantity of feed eaten or to the rate of intake during the 15 h following the afternoon feed delivery. Two main methods were used: modelling cumulative DMI evolution by an exponential model or by a segmentation-clustering method. The goat ability to sort against dietary fibre was also evaluated. There was a very good repeatability of the aggregate measures between days within a period for a given goat estimated by the day effect within breed and goat, tested on the residual variance (P > 0.95). The correlations between periods were the highest between the second and either the third or fourth periods. With increasing age, goats sorted more against the fibrous part of the TMR and increased their initial rate of intake. Alpine goats ate more slowly than Saanen goats but ate during a longer duration. Principal component analysis (PCA) was performed on all the aggregate measures of feed intake patterns. The factor score plots generated by the PCA highlighted the opposition between the different measures of feed intake patterns and the sorting behaviour. The projection of the animals on the scoring plots showed a breed effect and that there was a continuum for the feed intake pattern of goats. In conclusion, this study showed that the feed intake pattern was highly repeatable for an animal in a given period and between periods. This means that phenotyping goats in a younger age might be of interest, either to select them on feeding behaviour and choose preferentially the slow eaters or to adapt the quantity offered and restrict feed delivery to the fast eaters in order to increase feed efficiency and welfare by limiting the occurrence of acidosis, for example

Quantitative approach of acidosis in ruminants

The rumen acidosis is a common disease in high producing ruminants which received, then, a high-energy diet. This pathology is increasingly studied and many results are now available. These data were used to establish rumen pH response laws to various factors, linked with either feeding practices or not, which allow to deduce threshold values and ranges of optimum values for various criteria. The available results and the established models were considered first from a static point of view and then from a dynamic one. On this last aspect, interesting relationships were established between the dynamics of feeding behavior and pH. Moreover, bouts of acidosis altered rumen function only moderately and more severely intake and milk production with a long delay of recovery. Nowadays, promising research focused on acidosis deals with relationships between the characteristics of the rumen microbiota and its host.L’acidose du rumen est un trouble fréquent chez le ruminant à niveau élevé de performance et recevant, de ce fait, une ration riche en énergie. Elle est de plus en plus étudiée et de nombreux résultats sont maintenant disponibles. Ceux-ci sont utilisés pour établir des lois de réponse du pH du rumen à différents facteurs, alimentaires ou non, ce qui permet d’en déduire des valeurs de seuils et les zones de valeurs optimales pour ces différents critères. Les résultats disponibles et les modèles établis sont considérés d’abord d’un point de vue statique, puis d’un point de vue dynamique. Sur ce volet, des relations intéressantes sont établies entre les dynamiques d’ingestion et de pH. De plus, les épisodes d’acidose altèrent modérément le fonctionnement du rumen et, plus sévèrement, l’ingestion et la production laitière. Des recherches prometteuses mettent en relation l’acidose avec les caractéristiques du microbiote (l’ensemble des micro-organismes) du rumen et de l’hôte

Lameness in cows affects daily feeding time but not rumination time as characterized from sensors

Lameness in cows affects daily feeding time but not rumination time as characterized from sensors. 3. DairyCare Conferenc

Lameness affects cow feeding but not rumination behaviour as characterised from sensor data

Using automatic sensor data, this is the first study to characterize individual cow feeding and rumination behavior simultaneously as affected by lameness. A group of mixedparity, lactating Holstein cows were loose-housed with free access to 24 cubicles and 12 automatic feed stations. Cows were milked three times/day. Fresh feed was delivered once daily. During 24 days with effectively 22 days of data, 13,908 feed station visits and 7,697 rumination events obtained from neck-mounted accelerometers on 16 cows were analyzed. During the same period, cows were locomotion scored on four occasions and categorized as lame (n = 9) or not lame (n = 7) throughout the study. Rumination time, number of rumination events, feeding time, feeding frequency, feeding rate, feed intake, and milk yield were calculated per day, and coefficients of variation were used to estimate variation between and within cows. Based on daily sums, using each characteristic as response, the effects of lameness and stage of lactation were tested in a mixed model. With rumination time as response, each of the four feeding characteristics, milk yield, and lameness were tested in a second mixed model. On a visit basis, effects of feeding duration, lameness, and milk yield on feed intake were tested in a third mixed model. Overall, intra-individual variation was <15% and inter-individual variation was up to 50%. Lameness introduced more inter-individual variation in feeding characteristics (26–50%) compared to non-lame cows (17–29%). Lameness decreased daily feeding time and daily feeding frequency, but increased daily feeding rate. Interestingly, lameness did not affect daily rumination behaviors, fresh matter intake, or milk yield. On a visit basis, a high feeding rate was associated with a higher feed intake, a relationship that was exacerbated in the lame cows. In conclusion, cows can be characterized in particular by their feeding behavior, and lame cows differ from their non-lame pen-mates in terms of fewer feed station visits, faster eating, less time spent feeding, and more variable feeding behavior. Further, daily rumination time was slightly negatively associated with feeding rate, a relationship which calls for more research to quantify rumination efficiency relative to feeding rate

Revue sur les méthodes de dosage de la lignine utilisées en alimentation animale

International audienc

Résultats analytiques de la chaine Van Soest

Résultats analytiques de la chaine Van Soes

Traitements physiques

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