A comparison of two lamb production systems in New Zealand

Abstract

In New Zealand, a large proportion of lamb is produced during a condensed period. One method of providing a continuous supply of lamb for processing is to lamb more frequently. The objective of the current experiment was to compare ewe and lamb performance in a conventional once‐yearly lamb production system (CL) with an accelerated lamb production system (AL) over a 3‐year period using two breeds of sheep (East Friesian Composite (EF), and Romney). Ewe liveweights over the 3‐year period were higher in the AL ewes compared to the CL ewes (P < 0.05). Pregnancy rates were lower in the AL flock relative to the CL flock due to lower out of season reproductive performance (P < 0.001). Litter sizes were similar at birth but were higher in the CL flock at weaning (P < 0.001). Birth weights and, due to an older weaning age, weaning weights were heavier in the CL flock (P < 0.001). Growth rates were similar in EF lambs in both systems but were better in AL Romney lambs compared with CL Romney lambs. More ewes were bred in the AL flock, resulting in more lambs born and weaned per ewe per year. More frequent breeding of ewes resulted in an increase of 8% in weight of lamb weaned over the 3‐year experimental period.