Maternal care of rabbits in the lab and on the farm: endocrine regulation of behavior and productivity.

Maternal behavior in rabbits has been well described in the wild, the laboratory, and the farm. Salient characteristics include: (a) the construction of a nest (inside an underground burrow or a box), composed of straw/grass and body hair and (b) the display of a single, brief (ca. 3 min) nursing bout per day.

Fiber production and properties in genetically furred and furless rabbits.

The objectives of this study were to describe and compare means and measures of variability of fiber characteristics and fiber production between genetically furred and furless rabbits and among classes of furless rabbits. An F1 generation of rabbits was produced by mating New Zealand White does to a rare, furless Mini Lop buck. All F1 offspring had normal coats of fur.

Breed and heterotic effects on postweaning traits in Altex and New Zealand White straightbred and crossbred rabbits.

Postweaning data from 1,111 straightbred and reciprocally crossbred rabbits were analyzed to evaluate Altex and New Zealand White (NZW) breeds for individual growth and litter traits. The Altex is a recently developed sire breed, whereas the NZW is a popular commercial dam breed. Individual fryer growth traits were weaning (28 d; WW) and market (70 d; MW) weights and ADG.

Teaching international animal agriculture.

Students who major in animal science at U.S. institutions are generally exposed to a curriculum that emphasizes commercial, large-scale production of the few traditional food animals: cattle, poultry, sheep, and swine.

Maternal nest quality and its influence on litter survival and weaning performance in commercial rabbits.

Two hundred fifty parturition records on measures of maternal nest quality were collected over four seasons (S) from does (d; n = 108) of Californian (CAL), New Zealand White (NZW), and CAL x NZW breed types (DB). Service sires (s; n = 85) were from four sire lines (SL): CAL, NZW, and control and selected synthetics. Sires were nested within SL and 6-mo breeding cycle (C).

Preweaning variables' influence on market traits in rabbits.

Influence of several preweaning variables on market trait determination was investigated using 338 fryer rabbits from 52 litters. Variables measured at 1, 8, and 15 d included litter size, individual kit body weight (BW), within-litter rank score for BW, and litter uniformity (coefficient of variation for BW among littermates; CV). Daily milk consumption in wk 1, 2, and 3 was used to determine average weekly dominance rank score and total weekly milk consumption.

Mass selection for 70-day body weight in rabbits.

Five generations of phenotypic mass selection for increased 70-d body weight (market age, MW) were conducted in an experimental population of rabbits. Market-age weight was recorded for 1,616 rabbits from 336 litters (sired by 121 bucks and reared by 321 does). Additional growth and carcass traits measured in control (C) and select (S) lines were 28-d weaning weight (WW), 28- to 70-d average daily gain (ADG), carcass yield percentage (CY), loin primal cut percentage (LP), and lean-to-bone ratio in the loin primal cut (LBR).

Breed and environmental effects on postweaning growth of rabbits.

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).

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

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.

Evaluation of purebred and crossbred rabbits for carcass merit.

Two hundred twenty-six fryers representing four breed types, New Zealand White (NZW) and Californian (CAL) purebreds, CAL x NZW (CxN), and Flemish Giant (FG) terminal crossbreds (the latter group including FG x CAL, FG x CHA [CHA = Champagne D'Argent], and 1/2FG x 1/4CAL x 1/4CHA), were appraised for carcass merit. Evaluation criteria included the following: preslaughter and carcass weights; pelt, visceral, giblet, abdominal fat, and dressing percentages; percentages of carcass in loin, forequarter, and hindquarter primal cuts; and weight of lean in loin and ratio of lean to bone weight in loin cut. The least squares model consisted of breed type (B), season of birth (S), and gender (G) as fixed effects, B x G and S x G interactions, litter within B and S as a random variable, and random residual.

Prediction and causation of litter market traits from preweaning and weaning characteristics in commercial meat rabbits.

Market data on 1,315 rabbits from 201 litters from Californian (CAL), New Zealand White (NZW), CAL X NZW and NZW X CAL dams bred to CAL, NZW and Flemish Giant sires were subjected to multiple regression and path analyses. Market traits observed in litters at 56 d included average kit weight (A56W), litter size (LS56), total litter weight (L56W) and within-litter uniformity in individual weights (LCV). Preweaning variables as covariates included in the model were dam metabolic body weight (DMW), litter born (LSB), litter birth weight (LBW), milk yield from 1 to 21 d (MY) and feed intake from 1 to 28 d of the dam and litter (FI).

Effects of breed, parity, day of lactation and number of kits on milk production of rabbits.

Lactation records (n = 86) from 60 does of four breeds (Californian, New Zealand White, Palomino and White Satin) were analyzed to assess the effects of breed, parity, day of lactation and number of kits on milk production. Breed of doe tended (P less than .07) to be important for mean milk yield according to ANOVA results.

Cholesterol level of rabbit meat and trait relationships among growth, carcass and lean yield performances.

Data from New Zealand White rabbits (n = 89) were collected on growth, carcass and lean yield traits and on total lipid and cholesterol contents of total carcass lean tissue. Postweaning growth traits included individual 28-d weaning weight, 56-d market weight and average daily gain (28 to 56 d). Carcass yield traits included preslaughter, abdominal fat, giblet, pelt, visceral and carcass weights and dressing percentage; lean yield traits consisted of uncooked lean percentages from forequarter, hindquarter and loin primal cuts, adjusted total lean weight and overall meat to bone ratio.

Breed, heterotic and diet effects on postweaning litter growth and mortality in rabbits.

The effects of sire breed, dam genetic group and diet on postweaning litter growth and mortality were evaluated in 208 litters of rabbits. Sire breeds were New Zealand White (NN), California (CC) and Flemish Giant (FG). Dam genetic groups were NN and CC straightbred and California X New Zealand White (CN) and New Zealand White X Californian (NC) reciprocal crossbreds.

Doe reproduction and preweaning litter performance of straightbred and crossbred rabbits.

Reproductive characters (N = 430 matings) of four doe genetic groups and preweaning performance of litters (N = 280) were evaluated in a 15-mo study. Doe genetic groups were New Zealand White (NN) and Californian (CC) straightbreds and Californian X New Zealand White (CN) and New Zealand White X Californian (NC) crossbreds. Does and litters were provided either a commercial control or a 74% alfalfa pelleted diet.

Characterization of straightbred and crossbred rabbits for milk production and associative traits.

Two hundred twenty-five lactation and litter performance records from 82 does representing four genetic groups and two diets were analyzed to quantify breed, heterosis, reciprocal F1 cross and diet effects for milk production and associative traits. Doe genetic groups were New Zealand White (NN) and Californian (CC) straightbred and Californian X New Zealand White (CN) and New Zealand White X Californian (NC) reciprocal crossbreds. Pelleted diets fed to does and litters were either a commercial control or a 74% alfalfa diet.