P. Morand-Fehr

Effect of nutritional factors on fatty acid composition of lamb fat deposits

Abstract A literature review was made of the influence of nutritional factors on the fatty acid composition of fat deposits and muscles of lambs. A bibliographic data base, containing 979 observations from 108 papers, was made up in such way that one observation corresponded to one group of lambs in one experiment. Each nutritional factor was studied only when number of observations was sufficient. Consequently, special emphasis was given to the effect of dietary ingredients supplying energy or nitrogen on the fatty acid composition of subcutaneous (SC) and perirenal adipose (PR) tissues and in muscles of lambs. Regardless of sex, breed and breeding conditions, all the tissues examined showed a similar pattern of modification in fatty acid composition with diets. In milk fed lambs the pattern of fatty acids largely reflected the dietary fat pattern. The fatty acid of stored fats before weaning had an influence on fatty acid composition of fat deposits and muscle, several months after weaning. When the diets were rich in beet pulp or in fish meal the proportion of C 18:1 was significantly increased and the proportions of C 18:0 , C 18:2 and C 18:3 decreased in fat tissues. Inclusion of maize in diet resulted in an increase in linoleic acid content in fat deposits. Inclusion of cotton meal increased linoleic and stearic acids in fat deposits. Grass-based diets increased C 18:0 and C 18:3 in lamb tissues. Melting point of both SC and PR were strongly associated with differences in C 18:0 percentages. This approach underlined difficulties in understanding the diet effects on fatty acid composition of fat deposits and muscles without taking feeding and other management aspects into account. This study supported the extent to the modification of the fatty acid composition of lamb carcasses by choice of dietary ingredients despite the ruminal hydrogenation of dietary fat.

Diet effect on the daily feeding behaviour, frequency and characteristics of meals in dairy goats

Abstract An experiment of 4×3 weeks was carried out to analyse intake level and rate, number of meals and chewing activities of dairy goats. Four pairs of Alpine and Saanen goats in mid lactation were fed ad libitum four complete diets CR, CS, FR and FS in a Latin square design. Forage/concentrate ratio in these diets was low (C=30/70) or high (F=55/45) and starch, rapidly (R) or slowly (S) degradable in the rumen (barley and maize, respectively). The goats were housed in stalls and fitted with jaw movement recorders. Intake levels were also recorded over 4×48 h. Diets were distributed twice daily. Total daily intake was significantly higher ( P P P

Évaluation de différents paramètres permettant d'estimer la teneur en lipides des chèvres laitières selon leur stade physiologique

Introduction Une première étude (Morand-Fehr et al, 1990) a permis d’évaluer différents paramètres en tant qu’estimateurs de la teneur en lipides des chèvres en pleine lactation. En raison des grandes variations des réserves corporelles au cours du cycle gestation-lactation (Chilliard et al, 1987), il était nécessaire de préciser si leur aptitude à estimer cette teneur variait selon le stade physiologique des chèvres.

Estimation de la teneur en lipides des chèvres laitières par diverses méthodes informant sur le métabolisme lipidique ou l'état corporel

Matériel et Méthodes ― Dix chèvres Alpines et Saanen, âgées de 1 à 7 ans, reçoivent, entre la fin du 2e et la fin du 5e mois de lactation (abattage), une ration complète à base de foin de luzerne, de pulpes de betteraves surpressées et d’aliment concentré. Cinq chèvres reçoivent une quantité d’énergie inférieure à leurs besoins de 5 à 15%, les 5 autres une quantité supérieure de 5 à 15%. Chaque semaine, les chèvres sont pesées et les quantités d’aliments ingérés sont mesurées pendant 4 j. Chaque mois et juste avant l’abattage, des prélèvements de lait et de sang sont effectués en vue d’analyser la composition en acides gras du lait et les teneurs du plasma sanguin en acides gras non estérifiée (AGNE), en 3-hydroxybutyrate (3HB),