Genetic Evaluation of Some Doe, Litterand Lactiontraits of New Zealand White Rabbits

Abstract

Data collected on 765litters produced from 261 does and 69 sires of New Zealand White for five consecutive years. The data of doe traits (DBW = doe body weight, DPE = doe production efficiency), litter traits (LSB = litter size at birth, LSW = litter size at weaning, LW1, LW2, LW3 and LW4 = litter weight at 1 st , 2 nd , 3 rd week and 4 th week of age respectively, litter gain traits (LG1= litter gain from birth to 1 st week, LG2= litter gain from birth to 2 nd week, LG3= litter gain from birth to 3 rd week, LG4= litter gain from birth till to 4 th week of age resp.) and lactation traits (MY1, MY2, MY3 and MY4) = milk yield during the 1 st , 2 nd , 3 rd and 4 th week respectively, milk conversion ratio (MCR1, MCR2, MCR3 and MCR4 = milk conversion ratio from kindling till 1 st , 2 nd , 3 rd and 4 th week respectively (g litter gain per g of milk suckled during 1 st , 2 nd , 3 rd and 4 th weeks respectively of lactation).Heritability for doe traits were low (0.05 for DBW and 0.08 for DPE);h 2 were low ranged from 0.01 to 0.06 for litter size (LSB and LSW); from 0.0 7 to 0.20 for litter weights. The trend was the same in the case of both litter gain and milk traits. The highest repeatability R 2 estimates (0.74 and 0.76) were obtained for DBW and MCR4. R 2 estimates for other studied traits tended to be low to moderate in magnitude and ranged from 0.01 to 0.20 for litter traits and ranged from 0.14 to 0.40 for milk traits. The ranges of transmitting ability were 248.29 and 0.234 grams for DBW, DPE; ranged from 0.297 to 880.54 grams for litter traits, ranged from 0.383.22 to 416.29grams for milk yield, finally ranging from 0.584 to 5.06 % for milk conversion ratio from kindling till 1 st , 2 nd , 3 rd and 4 th week respectively. The percentages positive transmitting ability estimates were 48.41 and 47.52% for doe traits, ranged from 46.37 to 52.99% for litter traits and ranging from 33.63 to 46.50% for lactation traits. The ranges of transmitting abilities estimates for top 25% of animals were 121.28 and 0.117% for doe traits, ranged from 0.124 to 0.841% for litter traits. The rank correlation was negative, moderate and highly significant between DBW and DPE were generally positive,

Genetic parameters of growth traits and carcass weight of New Zealand white rabbits in a tropical dry forest area

“…The LWW is determined by the number of kits born and the mother’s milk capacity since she maintains the homogeneous weight in the litter, reduces competition in the udder, and increases its viability [ 9 ]. The LWW in this study was similar to that of Agea et al [ 18 ] and lower than the finding of El-Deghadi [ 3 ]. Then, the weight of the kits at weaning (WW) depends on the size of the litter, the weight being lower when the litter size is high [ 20 ]; from Table 1 , it is inferred that the average size of the litter at weaning was 5.68 kits, with a WW of 423.7 ± 14.5 gm.…”

“…Similar results for various litter-related traits were presented by Pycha et al [ 15 ], Behiry et al [ 30 ], and Karim et al [ 41 ]. For the WW and CW traits, the values obtained from r tend to be moderate; similar reports were presented previously [ 3 , 9 ].…”

“…In Colombia, rabbit production systems present little information on the genetic material available for production, which has caused producers to subjectively select replacement animals [ 2 ]. In animal genetic improvement programs, quantitative tools are applied that facilitate the selection of the best animals based on their breeding values to increase their productive and reproductive efficiency genetically [ 3 ]. In rabbits worldwide, in several productive variables, parent and offspring measurements, genetic and environmental parameters have been determined that influence the system’s productivity [ 4 – 6 ].…”

Genetic analysis of pre-weaning litter traits in V-line rabbits using a single-trait animal model

“…In general, estimates of h 2 a for litter traits were lower and ranged from 0.05 to 0.08 for litter size traits, 0.09 for both litter weight traits, and 0.14 for pre-weaning litter gain. These estimates were consistent with estimates of h 2 a in the relevant literature (Abou-Khadiga et al, 2012;El-Deghadi, 2019;Habib, 2011;Nagy et al, 2014;Nguyen et al, 2017). Consistent with these studies, the lower estimates of h 2 a for litter traits may be due to the relative importance of additive genetic factors being low.…”

“…CV % estimates for litter traits (Table 1) increased from birth to weaning, showing that phenotypic variance was lower at birth than at weaning. However, these estimates showed that improving these traits through phenotypic selection is quite possible (Shehab El-Din, 2016;El-Deghadi, 2019). In this respect, Youssef et al (2008) suggest that the higher variation in litter traits at weaning than at birth would lead to greater phenotypic improvement in these traits by selection associated with good management during the suckling period.…”