New Zealand Journal of Agricultural Research abstracts

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A comparison of two lamb production systems in New Zealand

G. deNicolo

S. T. Morris^*

P. R. Kenyon

P. C. H. Morel

College of Sciences
Massey University
Private Bag 11222
Palmerston North 4442, New Zealand

^*Corresponding author: s.t.morris@massey.ac.nz

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.

Keywords frequent lambing; multiple lambing; pregnancy rates; sheep; year-round lambing

A07171; Online publication date 15 August 2008; Received 27 August 2007; accepted 25 June 2008

New Zealand Journal of Agricultural Research, 2008, Vol. 51: 365–375
0028–8233/08/5103–0365 © The Royal Society of New Zealand 2008

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