Dairy goat performance with different dietary concentrate levels in late lactation

Optimal feeding programs for dairy goats in late lactation and when dry are not well established. Dietary characteristics influence milk yield and body condition of dairy goats, as well as growth of primiparous goats. Hence, objectives of this experiment were to determine effects of dietary concentrate and energy levels in late lactation and the dry phase on performance of Alpine yearling doelings and mature does in late lactation and the subsequent early lactation phase. The experiment consisted of 16 weeks in late lactation, 8 to 13 weeks dry, and 12 weeks in the subsequent lactation. Diets of 20, 35, 50, or 65% concentrate (2.18, 2.34, 2.49 and 2.62 Mcal/kg metabolizable energy [ME], respectively) were consumed free-choice in late lactation, with a 35% concentrate diet (2.18 Mcal/kg ME) in the first 4 weeks of the dry phase and 50% concentrate (2.65 Mcal/kg ME) until kidding. All goats consumed a 50% concentrate diet (2.42 Mcal/kg ME) in the subsequent early lactation. Yearling doelings and mature does differed in milk yield response to dietary concentrate and energy levels in late lactation, with no effect for doelings and increased milk yield for does as the concentrate level increased to 50% (2.49 Mcal/kg ME). Conversely, a 65% concentrate diet depressed milk yield in late lactation by does compared with 50% concentrate. Dietary concentrate level may have little effect on subsequent lactational performance with adequate nutritional planes in subsequent dry and early lactation phases, for both mature does and yearling doelings incurring significant growth.