Increasing lamb survival will increase the number of lambs weaned. Generally, as lamb litter size increases, so too do lamb losses. Lambs born of optimum birth weight have higher survival rates. The estimated financial benefit to industry could come to $28.2million per year, if 50% of farms improved lamb survival by 1% to 5%. These values are farm-gate returns only. Benefits to New Zealand (based on FOB export returns) would increase these values by about a further 50%. Improving survival rates also have animal welfare and market access benefits.
Ovita is developing a lamb survival recording module for breeders, incorporating birthweight information, cause of death information and survival rate to 3 days of age and to weaning age. Genetic progress in lamb survival is possible if both maternal and direct genetics are considered for singles, twins and triplets.
The lamb survival resource animals, developed from 2003, consist of 47 flocks and over 1000 industry sires and their progeny. The traditional breeds, Romney, Perendale and Coopworths make up 50% of this resource.
Forty five of the flocks were studied and showed that the mean survival rate from birth to 3 days was 92%. Post-mortem of dead lambs of full gestation showed that 2% of all lambs were not alive at birth, 2% died as a result of difficult births (dystocia) and 2% of all lambs born died from starvation/exposure between birth and 3 days. The average birth weight was 4.9kgs.
Genomic breeding values (gBVs) for the lamb survival traits, including the direct lamb survival trait, are expected to be released in 2012.
How can you help?
To generate gBVs we need sire DNA from Romney, Perendale, Coopworth, Texel and composite SIL recorded flocks. Genomic BVs for each of these breeds can then be developed for industry use. Any breeders interested in contributing please contact Julie Everett-Hincks firstname.lastname@example.org or Lucie Archer email@example.com .
There are currently no specific genetic tests for lamb survival (direct).