Geenty says today’s higher lambing percentages mean planning and management need to be more finely turned, particularly around matching feed supply with animal demand.
“Changes to farm systems could include wintering fewer ewes, lambing later and drafting lambs earlier. The critical on-farm elements – or ingredients – are pasture cover, ewe weight and condition score, pregnancy scanning, lambing management, lamb growth rates and overall animal health.”
Geenty says improving lambing percentage need not be complicated, but it does require attention to detail.
“Given individual animals make up the flock average, the aim is to improve the performance of as many individual animals as possible, thereby lifting that average.”
Hogget lambing: Geenty says farmers, quite rightly, are still enthusiastic about hogget lambing.
“Each hogget lamb is a ‘bonus’, if the job is done correctly. This means that hoggets need to be in good liveweight and body condition at mating, lambed later than the ewe flock, have lambs weaned a little earlier, and be fed well for good body weight and condition at the following mating. Hoggets that lamb will need about 15% more feed than those that don’t lamb.”
Feeding multiples: Ewes carrying multiples should always be priority fed, as they are the most efficient lamb producers.
“This means good feeding of the ewe flock pre-mating to get as many multiples as possible ‘on board’. Then, once pregnancy scanning has identified the multiples, prioritise them pre- and post-lambing for good lamb survival, good lamb growth rates, and good ewe liveweight and body condition for the following mating.”
Should triplet-bearing ewes be prioritised further? Geenty says separating triplets from twins is important only when there is a significant number of ewes with triplets.
“That is, if your flock is lambing above 160% or scanning above 185%.”
Next lambing percentage breakthrough?: Because much of the influence on lamb viability is environmental – feeding, weather, etc – there is unlikely to be one technology that generates a marked improvement, Geenty says.
“The most likely new technology is identification of ewe and/or lamb genetic markers for indicators of improved mothering/lamb survival. We do know now that some sires have progeny with better survival than others, but don’t really understand why.”
The latest edition of “Making every mating count” can be found as a pdf on B+LNZ’s website (www.beeflambnz.com) or phone 0800-BEEFLAMB for a copy.
What happens to potential lambs?
A 1980 survey of South Island farms showed the average number of eggs shed for 100 ewes mated was 161, yet average scanning was 134% and average tailing was 121% – a loss of 40 potential lambs.
While this information is now more than 30 years old and involved only South Island flocks, the insights into where “eggs” – potential lambs – were lost are still relevant.
Geenty says it is worth noting that, while 40 potential lambs were lost for 100 ewes mated, the performance of some farms was outstanding while others had huge losses (as indicated by the ranges shown within brackets).
– Supplied, Beef + Lamb NZ.
