Effect of nutrition from mid-pregnancy to parturition on the live weight of twin-bearing hoggets and the live weight and survival of their lambs

This experiment investigated the effect of two nutritional levels (medium and ad libitum) from day 85 of pregnancy until parturition on the live weight and metabolic status of twin-bearing hoggets, and the gamma-glutamyl transferase and glucose concentration on the day of lambing (L1), survival and live weight of their offspring until L29. The mean live weight of the ad libitum treatment hoggets (66.3+/-0.6 kg) was greater (P<0.05) at P145 than that of medium treatment hoggets (63.6+/-0.5 kg). Hogget live weight did not differ (P>0.05) between treatments at L29 (60.9+/-0.9 vs 60.0+/-1.0 kg for the medium and ad libitum treatment hoggets, respectively). The birth weight of lambs born to ad libitum ewes (4.0+/-0.1 kg) was greater (P<0.05) than that of lambs born to medium treatment ewes (3.7+/-0.1 kg). At L29, lamb live weight did not differ (P>0.05) between treatments (11.2+/-0.3 vs 11.3+/-0.3 for the medium and ad libitum treatments, respectively). Lamb survival did not differ (P>0.05) between treatments. There was no difference between treatments in the efficiency of lamb live weight produced. These results indicate that offering twin-bearing hoggets ad libitum levels of herbage from day 85 of pregnancy until parturition is not an efficient technique to increase lamb production from these hoggets. Farmers should, therefore, offer 1000-1400 kg DM/ha to optimize lamb production from twin-bearing hoggets.