Influence of short-term feed restriction on milk production traits of Sarda dairy ewes.

The effects of short-term feed restriction on milk yield and milk composition of Sarda dairy ewes were studied in a 17-d experiment. Twenty sheep were housed in individual pens and divided in two isoproductive groups. Ten ewes (feed restricted group, FRG) were fed a total mixed ration pelleted diet (TMR-PD) ad libitum (average intake of 2.5 kg/head per day) for 7 days (preliminary period), followed by 3 days of feed restriction of 50% of their previous intake (1.25 kg/head per day of TMR-PD) and 7 days of recovery. The other ten ewes (control, C group) were fed TMR-PD ad libitum during all the experimental period (average intake of 2.5 kg/head per day). There were no differences in milk yield between the two groups during the preliminary period (1485 and 1493 g/d for FRG and C group, respectively). Milk yield for the FRG decreased during the feed restriction period and averaged 72% of the values of the C group (1009 vs 1389 g/d, P≤0.001). Milk yield of the FRG was not completely restored during the 7-d recovery period, remaining lower than that of the C group (1278 vs 1451 g/d, P=0.12). Fat percentage tended to increase in FRG during the feed restriction period (5.87% vs 5.27%, P=0.08), and remained higher than that of the C group during recovery (6.04% vs 5.20%, P≤0.01). No effects of feed restriction on protein percentage (5.52% vs 5.53% for FRG and C group, respectively) were observed. SCC was lower in the FRG than in the C group during the preliminary period (Ln SSC 4.51 vs 4.71, P=0.06), increased by more than 4 fold during the feed restriction period (Ln SSC 5.34 vs 4.76, P=0.02) and remained higher during the recovery period (Ln SSC 5.4 vs 4.8, P=0.10). Short-term feed restriction caused a permanent drop in milk production and an increase in SCC on dairy ewes. [ABSTRACT FROM AUTHOR]