Abstract

Previous work estimating the impact of differential feeding of ewes during pregnancy, on lamb wool follicle development, has been done primarily with single- and twin-bearing ewes. The aim of this study was to compare the follicle development and fibre characteristics of twin- or triplet-born/reared lambs, born to ewes offered different sward height allowances during pregnancy and lactation. After pregnancy scanning, 186 twin- and triplet-bearing Romney ewes with 6 weeks wool growth, were randomly allocated to four different sward heights (2, 4, 6 and 8 cm). Within the first 24 hours of parturition ewes were transferred to one of two sward heights (4 and 8 cm). The wool and follicle characteristics of twin- (n = 65) and triplet-born (n = 63) ewe lambs were compared. Fleeces from triplet-born lambs were lighter (1.59 kg vs 1.82 kg, P < 0.05) and finer (32.7 μm vs 33.4 μm, P < 0.05) than those from their twin-born counterparts. Lambs born to ewes offered higher sward heights during pregnancy had increased loose wool bulk (P < 0.01). Although increasing sward height during pregnancy increased fibre diameter in twin-born lambs, there was no similar relationship for triplet-born lambs (P < 0.05). Sward height during pregnancy had no effect on secondary follicle number in twin-born lambs but, triplet-born lambs born to ewes grazed on the 4 cm sward tended to have significantly higher numbers of secondary follicles than those grazed on 6 cm (89.2 vs 66.0, P < 0.05). More work is necessary to determine whether this interaction has practical implications for breeding replacements. Nutritional treatments during lactation had no significant effects on lamb wool characteristics. KEYWORDS: feeding; nutrition; follicle development; wool bulk; wool characteristics.

RG, Sherlock, PR Kenyon, and ST Morris

Proceedings of the New Zealand Society of Animal Production, Volume 65, Christchurch, 168-172, 2005