
TY  - JOUR
A1  - Hall, DG 
A1  - Fogarty, NM 
A1  - Gilmour, AR 
T1  - Performance of crossbred progeny of Trangie Fertility Merino and Booroola Merino rams and Poll Dorset ewes. 1. Lamb birth weight, survival and growth
JF  - Australian Journal of Experimental Agriculture
JO  - Aust. J. Exp. Agric.
Y1  - 1995
VL  - 35
IS  - 8
SP  - 1069
EP  - 1074
KW  - 
UR  - https://doi.org/10.1071/EA9951069 
N2  - Merino rams of the Trangie Fertility and Booroola strains were joined to Poll Dorset ewes in single sire mating groups over 3 years. Forty sires produced a total of 1250 lambs in 885 litters from 451 ewes. Lamb birth weight averaged 4.1 kg, 80.8% of lambs survived to 3 days of age and growth rates to weaning (mean 93 days) averaged 289 g/day. Lambs with Trangie Fertility sires grew 15 g/day faster and were 1.3 kg heavier at weaning than those lambs with Booroola sires (P<0.001). There were no effects of sire strain on birth weight or lamb survival. Birth weight increased with dam liveweight in mid-pregnancy (P<0.001), and weaning weight and growth rate increased with dam liveweight at joining (P<0.001). Survival of lambs was predominantly a function of birth weight. Lambs weighing 4 kg at birth from primiparous dams had survival rates of 76% compared with 88% for lambs from multiparous dams (P<0.01). No lamb under 2.0 or over 6.3 kg survived, and 48% of deaths occurred within 1 day of birth. Dystocia, particularly of heavy, single-born lambs, caused 53% of observed lamb deaths. For the traits birth weight, lamb survival, weaning weight and growth rate, the direct heritabilities were 0.24 ¦ 0.10, 0.05 ¦ 0.05, 0.19 ¦ 0.10 and 0.12 ¦ 0.08 respectively; the corresponding maternal heritabilities were 0.08 ¦ 0.05, 0.05 ¦ 0.04, 0.05 ¦ 0.05 and 0.07 ¦ 0.05 respectively; and the common environmental effects among litter mates (c2) were 0.57 ¦ 0.08, 0.47 ¦ 0.08, 0.15 ¦ 0.08 and 0.13 ¦ 0.08 respectively. 
ER  -

