Tuesday, January 7, 2014

Lambs With Hairy-Coats Have Higher Survival

French researchers determined hair coat to be an important factor affecting lamb survival and growth in a prolific breed of sheep adapted to harsh conditions.The Romane breed shows large variability in fleece type at birth and it has been suggested that lamb survival could be related to birthcoat type.

Lamb with hairy coat
A total of 7,880 lambs from 104 sires and 1,664 dams were used in a 14-year experiment to determine the effects of birthcoat on lamb survival and growth. Birthcoat type, coat surface temperature, coat depth, lamb survival, and growth were measured from birth to weaning. Weather data were recorded daily during lambing time.

Two types of coats were observed at birth: hairy coat (62.9% of lambs) with a long coat depth (0.92 in) and woolly (37.1 of lambs) with a short coat depth (0.33 in). Total mortality rate was significantly less in hairy-bearing coat lambs than in short-woolly coat ones at 2, 10, and 50 days of age.

At birth, a significant lower coat surface temperature, indicating less heat loss, was observed in long-hairy coat lambs compared with others (70°F vs. 79°F). Heavier body weights and better growth performances up to the age of 50 days were observed in long-hairy-bearing coat lambs. Lamb survival was positively correlated to weather conditions at lambing time in short-woolly lambs, whereas no relation was observed in hairy-coat lambs.

Genetic correlations between birthcoat type, lamb survival, and live body weight at birth were positive and moderate, suggesting that it would be beneficial to take birthcoat into account as an adaptive trait in any genetic strategies for sheep production in harsh conditions on rangelands. Heritability estimate of birthcoat type (hairy or woolly) is high (0.88).

Source:  Journal of Animal Science, January 2014 (abstract).


Martha McGrath said...

but doesn't a hairy birthcoat mean the sheep is likely to have a kempy fleece?

Susan Schoenian said...

Yes. But these are meat sheep. The breed used in the research is a breed that has coats with a mixture of hair and wool. Similar to Katahdin.