Influence of dietary protein on performance of dairy goats during pregnancy

An experiment was conducted utilizing 44 Alpine does (48 kg of BW) to examine the effects of dietary protein intake on nutritional status and performance of does during the latter half of pregnancy and parturition. All dry does were bred, confirmed pregnant, and fed a diet containing 9% CP and 2.04 Mcal of metabolizable energy/kg of DM through wk 11 of gestation. On wk 12, does were blocked by BW and assigned to one of three dietary treatments: 8.8% (low) CP, 11.0% (medium) CP, and 14.3% (high) CP. All diets were isocaloric (2.04 Mcal of metabolizable energy/kg of DM) and fed for ad libitum intake from wk 12 of gestation until parturition. Average CP intakes for low, medium, and high protein were 164, 220, and 303 g/d, respectively. Body weight gains increased with increasing CP intake. Kidding rates were 79, 100, and 93% for the low, medium, and high protein groups. Gestation length, litter size, and litter weight did not differ among treatment groups. Urea N in jugular blood plasma increased with increasing CP intake. Plasma glucose and whole blood beta-hydroxybutyrate tended to increase with increasing CP intake. Plasma glucose decreased 7, 6, and 3%, and NEFA increased 97, 400, and 187% between wk 13 and 21 of gestation for the low, medium, and high protein diets, respectively. The data suggest that the low protein diet may be inadequate to meet the does' protein requirement during late gestation, but there was no apparent advantage in feeding the high rather than medium protein diet. Intake of CP for the medium protein diet, 9.8% g/kg of BW.75, was 40% higher than that recommended by the NRC for pregnant goats.