[Dietary behavior and digestion of a constant composition feed in the dairy cow at the end of gestation and the beginning of lactation].
Five cows, fitted with rumen and duodenal fistulas, were given ad libitum a small amount of hay and a stable ration of 60 p. 100 maize silage and 40 p. 100 concentrate from 4 weeks before calving of 6 weeks after. The pattern of feeding behaviour and of digestive processes was recorded over the whole period. The following results were obtained: 1) While the amounts of the ingested dry matter of the ratio increased by 40 p. 100, the digestibilities of dry matter, organic matter, crude fiber and starch decreased by an average of 7, 7, 10 and 5 points p. 100 between 2 weeks before calving and the second week after. These values then increased by 3, 3, 3 and 1 points p. 100 between weeks 2 and 6 after calving (fig. 1). 2) The duration of intake and rumination increased rapidly while the rates varied little (fig. 2). At the same time, the number of meals, length of small meals and rumination periods increased, but the length of large meals was minimal around calving time (fig. 3). Consequently, the distribution of intake during the light/dark cycle was modified (fig. 4). 3) The preprandial ammonia content of the rumen liquor was minimal (20 mg/l) the second week of lactation. The volatile fatty acid content and the proportions of different acids varied little throughout the period (fig. 5). 4) The flux of organic matter, non-ammonia nitrogen and starch to the duodenum increased rapidly but the amounts of organic matter digested in the rumen varied little, while those digested in the intestine multiplied almost 3 times, corresponding to a considerable decrease in rumen digestion (table 3, fig. 6). The amino acid composition of duodenal nitrogen varied little between the end of pregnancy and the onset of lactation (table 4).
D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004063:Digestion; D004386:Duodenum / Q000378:metabolism; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D005285:Fermentation; D007774:Lactation; D049590:Postpartum Period; D011247:Pregnancy; D011270:Pregnancy, Animal; D012417:Rumen / Q000378:metabolism; D013997:Time Factors
Comportement alimentaire et utilisation début de lactation.