Genetic Variance Component Analysis of Litter Size and Weaning Weight of New Zealand White Rabbits

Rollins, W. C.; Casady, R. B.; Sittmann, K.; Sittmann, D. B.

doi:10.2527/jas1963.223654x

Cited by 16 publications

(9 citation statements)

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“…Conversely, the parity class of dam effect was never a significant source of variation. In contrast to the present results, Rollins et al (1963) found parity class of dam to influence litter size and total weight at 56 d. Rouvier et al (1973) reported parity effects for litter size, survival rate, and total litter and average fryer weight at 56 d. In addition, Lukefahr et al (1983~) reported parity influences on litter feed intake, feed efficiency, and litter weight at 56 d. The 7 0 d end-point trait performances measured in the present study, as opposed to 5 6 d performances reported in the literature, may have been less influenced by residual maternal effects of parity. For average market weight per fryer, the sex effect approached significance (P < .13), with males tending to weigh more than females (2,063 vs The overall linear covariate of litter size at weaning was related (P < .01) positively to litter weaning weight, total feed intake, weight gain, and market weight at 70 d and negatively to litter feed efficiency (Tables 2 and 3); however, within-breed-type regressions were never significantly different.…”

Section: Results and Dlscussioncontrasting

confidence: 99%

Comparison of rabbit breed types for postweaning litter growth, feed efficiency, and survival performance traits

Ozimba

Lukefahr

1991

Journal of Animal Science

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Postweaning data on 643 rabbits from 122 litters representing four breed types, New Zealand White (NZW) and Californian (CAL) purebreds, CAL X NZW (CXN), and Flemish Giant (FG) crossbreds (the latter group was a collection of FG X CAL, FG X Champagne D'Argent [CHA], and 1/2 FG X 1/4 CAL X 1/4 CHA), were gathered over five seasons and compared for growth, feed efficiency, and survival-related performance traits. Evaluation criteria included litter size and weight at weaning (28 d); 28- to 70-d litter feed intake, weight gain, feed efficiency, and mortality rate; and litter and average market weight (70 d). The least squares model included main effects of breed type, season of birth of the litter and parity of dam, litter size at weaning as a linear covariate, and the random error. Breed-type differences were not detected for litter size and weight at weaning and feed efficiency. Purebred NZW and CAL litter trait performances were comparable (P greater than .05). Purebred NZW litters consumed less feed than CXN and FG crosses, gained weight less rapidly than FG crosses, and weighed less per fryer at 70 d than CXN and FG crosses (P less than .05). Feed intake was lower and average market weight was lighter for CAL purebred litters than for CXN and FG crossbred litters (P less than .05). The CXN and FG crossbreds only differed (P less than .05) for average market weight (2,078 vs 2,192 g). Mortality rate was lower (P less than .05) in CXN crossbred litters than in CAL purebred litters.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Results and Dlscussioncontrasting

confidence: 99%

Comparison of rabbit breed types for postweaning litter growth, feed efficiency, and survival performance traits

Ozimba

Lukefahr

1991

Journal of Animal Science

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“…0194) for pre-weaning mortality in Giza White rabbits suggests that selection for decreased mortality to weaning should be effective in this breed. This estimate appears to be higher than the estimate of 0-12 obtained by Rollins, Casady, Sittmann and Sittmann (1963) for New Zealand White rabbits.…”

Section: Components Of Variance and Heritability Estimatescontrasting

confidence: 78%

A genetic analysis of litter traits in Bauscat and Giza White rabbits

1987

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An analysis of doe productivity traits was carried out on 884 litter records including 52 sires and 210 daughters (paternal half sisters) of Bauscat (B) and Giza White (G) rabbits. Traits examined included litter size and weight at birth and at weaning, pre-weaning mortality and mean weight of young at weaning. Year-of-kindling affected most litter traits but no pattern of parity effects on litter size and pre-weaning mortality was observed. Litter weight and mean weight of young at weaning generally increased linearly as parity advanced. Litter size and weight and mean weight of young tended to increase as month of kindling advanced from October to March, and to decrease again during April and May. Pre-weaning mortality decreased as month of kindling advanced up to March and increased thereafter during April and May. The sire of the doe affected all litter traits studied, with the exception of litter size at birth and pre-weaning mortality in the B breed. Estimates of heritability for most of the litter traits were moderate or high. Genetic and phenotypic correlations among litter size traits and between litter size and litter weight traits were positive and relatively moderate or large. Litter weight traits were positively correlated both genetically and phenotypically. The genetic and phenotypic correlations between litter size traits and mean weight of young at weaning were negative and relatively moderate or large.

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“…Paradoxically, due to the experimental sensitivity involved in this large data set, these differences were statistically significant, although the biological importance is questionable. Unlike in most domestic livestock species, the sex effect does not strongly influence weaning-to-market growth and carcass characters in rabbits (Rollins et al, 1963;Vogt, 1979;Lukefahr and Ozimba, 1991;Ozimba and Lukefahr, 1991). In addition, a significant breed x sex interaction was detected for GAIN.…”

Section: Resultsmentioning

confidence: 74%

Breed and environmental effects on postweaning growth of rabbits

McNitt

Lukefahr

1993

Journal of Animal Science

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Growth records of 4,270 weanling rabbits born between March 1985 and December 1989 were studied to evaluate the effects of breed and month of birth on postweaning growth performance of four medium-sized breeds. Californian (CAL), New Zealand White (NZW), Palomino (PAL), and White Satin (WS). Traits examined were 28-d weaning weight (WW), postweaning gain (GAIN), attainment of 1,600-g market weight by 76 d of age (MKT), and approximate age at 1,600 g (AGE). Least squares models included breed, month of birth, sex, and year of birth as fixed effects and litter within breed by month and by year and the residual as random variables. The NZW had significantly higher GAIN and MKT and lower AGE than the other three breeds. White Satin had the highest WW, followed by CAL, NZW, and PAL. White Satin had higher GAIN and lower AGE than PAL or CAL but did not differ for MKT. Poorer performance was seen during the summer, but the NZW tended to be less affected by the environmental extremes than the other breeds. The effects on GAIN of mean monthly temperature and daylength and the interrelationships of these with estimated milk production and litter size at weaning were evaluated by regression methods for the 2,100 NZW fryers. Temperature and daylength had significant effects on GAIN, with lowest GAIN in the summer, but the individual contributions to the variance were small because of some redundancy when month, temperature, and (or) light were included in the same model. Curvilinear trends were observed that favored GAIN as estimated milk production increased but decreased GAIN as litter size at weaning increased. In the hot, humid climate of southern Louisiana important breed differences were noted. There were also indications that daylength may be an important factor in postweaning fryer performance.

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Genetic Variance Component Analysis of Litter Size and Weaning Weight of New Zealand White Rabbits

Cited by 16 publications

References 0 publications

Comparison of rabbit breed types for postweaning litter growth, feed efficiency, and survival performance traits

Comparison of rabbit breed types for postweaning litter growth, feed efficiency, and survival performance traits

A genetic analysis of litter traits in Bauscat and Giza White rabbits

Breed and environmental effects on postweaning growth of rabbits

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