Effect of high fat diets on the performance, milk yield and milk composition of multiparous rabbit does

Experiment 1. One hundred and twenty-five lactations from 88 New Zealand X Californian does were used to study the influence of high fat diets on the performance and milk yield of multiparous rabbit does in two high productivity situations: housed in hot conditions (minimum temperature above 24 degrees C) with eight pups (group H8), or housed in warm conditions (minimum temperature under 21 degrees C) with 11 pups (group W11). Starting from a control diet (diet C) with 26 g ether extract (EE) per kg dry matter (DM), two isoenergetic diets were formulated adding fat from vegetable sources up to 99 g EE per kg DM (diet V) or animal sources up to 117 g EE per kg DM (diet A). The lactating does showed similar food daily intakes (approximately equal to 105 g DM per kg), therefore digestible energy intake of does on high fat diets was significantly higher (P < 0(.)001). The addition of fat to the diets increased (P < 0(.)001) milk yield of does (+21 and 24 g/day for diets V and A, respectively) and litter weight at weaning (P < 0(.)05) and decreased the number of pups replaced (P < 0(.)01) during lactation. Group H8 does had significantly lower DM intakes, litter growth rates and milk production levels than group W11 does (P < 0(.)001). Experiment 2. The effect of these diets on milk composition was determined in 62 lactations from 28 multiparous rabbit does, in which litter size was maintained at eight pups. Milk samples were collected manually on the 7th, 21st and 28th days of lactation. Milk of does given high fat diets, especially diet A, had higher fat and energy content (P < 0(.)001) and a lower protein content (P < 0(.)001) than those given diet C. Milk of does given diet A, had a greater DM content than those given the diets C or V (P < 0(.)001). There was a correlation between the fatty acid composition of milk and dietary fat. The proportion of odd chain fatty acids in the milk fat was lower for does given diet V (P < 0(.)05) than those given diet A. In conclusion, high fat diets were related to a higher milk yield and energy content of milk, allowing a higher litter weight gain and a lower mortality of sucking pups.