Effects of forage to concentrate ratio on the lactational performances of high- and mid-yielding dairy ewes in early-lactation

摘要

Milk yield and milk composition are negatively correlated in sheep (Pulina et al., 2006), as in other species. Increasing the rate of concentrate in the diet of dairy ewes allow increasing daily energy intake to cope with requirements, but it might reduce milk fat content whereas increases body fat deposition (Bocquier & Caja, 2001). However, when level of concentrate exceeds 50% DM of the diet, subacute rumen acidosis is expected, which impairs fiber digestion and compromise milk yield and composition (Sutton & Morant, 1989). The effect of forage:concentrate ratio (F:C) on milk quality has been studied extensively in cattle and goats, while it received less attention in dairy ewes (Bocquier & Caja, 2001). The objective of this work is to study thelactational response of dairy ewes to different levels of concentrate (70:30 to 40:60) in the diet of high and mid-yielding dairy ewes.