Effect of non-structural carbohydrate dietary content on the productive performance of Sarda primiparous ewes

Abstract

In order to enhance our knowledge of milk sheep rationing, 30 Sarda primiparous ewes, for which single birth was diagnosedby ultrasonography prior to lambing, were divided into two homogeneous groups (L-NSC and H-NSC) and fed isoproteicdiets containing different amounts of non-structural carbohydrates (NSC, 36 vs 40 % DM). The lambs wereweighed both at birth (between February and March 2002) and at sale (about one month later) in order to estimate milkproduced by their mothers during the lactation period, by using a specific equation developed on Sarda ewes. Individualmilk yield and quality were then monitored monthly until the ewes dried off (July 2002). Our results showed that groupH-NSC (which received the diet with the highest NSC content) was associated to the highest milk yield (Pthe suckling period. In contrast, in the milking period group L-NSC showed significantly higher (P(996.2 vs 899.8 g/d) and fat and protein corrected milk yield (979.6 vs 877.7 g/d). Dietary treatments did not significantlyaffect milk composition.In conclusion, considering the milk production of each group as a function of the lactation month, group H-NSC had itsbest performance during the first two months of lactation, while group L-NSC was more productive during the remainingmonths. Also the percentage of protein, fat and casein of the milk during milking showed a similar trend. While the latterparameters were higher in the H-NSC group during the first two months of milking, from the 4th control onward higherlevels were observed in the L-NSC group. These results suggest, at least for Sarda primiparous ewes, the adoption ofdiets with different contents of non-structural carbohydrates according to the productive period (40 %, DM basis, in thefirst two months of lactation, 36 %, DM basis, in subsequent months).

Keywords

• Non-structural carbohydrates, Sarda ewes, Milk production