CORRELATED RESPONSE ON LITTER TRAITS AND MILK YIELD IN NEW ZELAND WHITE RABBITS SELECTED FOR LITTER SIZE AT BIRTH | ||||
| Egyptian Poultry Science Journal | ||||
| Article 2, Volume 40, Issue 3, September 2020, Page 599-612 PDF (585.2 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/epsj.2020.114314 | ||||
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| Authors | ||||
mahmoud mostafa El-Attrouny 1; Walid shabaan Habashy 2
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| 12Department of Animal Production, Faculty of Agriculture at Moshtohor, Benha University, Egypt | ||||
| 2Dept. of Anim. and Poult. Prod, Fac. of Agric., Damanhour Uni., Egypt | ||||
| Abstract | ||||
| The current study evaluated the influence of selection for litter size at birth on litter traits and milk yield of New Zealand White (NZW) rabbits. A total of 2231 litters produced from 360 does and 72 bucks were used to assess litter size at birth (LSB) and weaning (LSW), litter weight at birth (LWB), litter weight at 21 d (LW21) and litter weight at weaning (LWW), as well as mortality percentage (MOR%) from birth (total alive) till weaning age, milk yield at lactation intervals of 0–7 d (MY07), 7-14 d (MY14), 14-21 d (MY21), 21-28 d (MY28) and 0-28 d (TMY) and milk conversion ratio during 21 d of lactation (MCR021). Multi-trait animal model was used to data analysis using VCE6 programe. Estimates of heritability for litter traits were low and ranging from 0.05 for LSB to 0.14 for LWB. Also, estimates for milk yield traits were low and ranged from 0.08 for MY7 to 0.22 for MY21. The contrast among these generations were significant (P<0.05), favoring the selected generations over the base population. Estimates of genetic correlations between litter traits were positively and ranged from low (0.06) between LSW and LWB to moderate (0.51) between LWB and LW21. Genetic correlation between milk yield traits at different periods of lactation ranged from low (0.19) between MY7 and MY28 to high (0.84) between MY21 and TMY , while negative correlation between MY7 and TMY (-0.29). The accumulative correlated selection responses were positively and significant for litter traits and milk traits, while neagative and significant for MOR % , positive and non significant for MCR%. Conclusively, The selection of NZW does for litter size at birth could be efficient to improve litter traits and milk yield traits | ||||
| Keywords | ||||
| correlated response; contrast; litter traits; milk yield; heritability; selection | ||||
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