Genealogical data of Boer and Nubian goats in Mexico.

The pedigree file of the Boer and Nubian goat breeds in Mexico was constructed using the national database provided by the Asociación Mexicana de Criadores de Ganado Caprino de Registro. Field technicians routinely updated the goat national database by recording information from flocks participating in the performance-recording system. Information on animal identification number, parents, birth date, sex, breed, and farm of origin were used to undertake pedigree analyses using the ENDOG program (version 4.8). This paper presents a pedigree data file, tables and figures of characteristics of pedigree data, pedigree analyses, pedigree integrity, effective population size and genetic conservation index. The data can be used to estimate other population parameters, to monitor the genetic diversity of the Boer and Nubian goat breeds in Mexico, and also to design balanced breeding programs, maintaining genetic variation at reasonable levels and maximizing genetic progress in these populations.

Dataset on growth curves of Boer goats fitted by ten non-linear functions.

Data on the description of growth of female Boer goats from the Mexican national breeding flock are presented. Goat meat is highly appreciated for the preparation of traditional dishes of Mexican cuisine, and its demand is on the rise. Boer goats are of relatively recent arrival in Mexico and the size of the performance-recorded flock has been increasing steadily in the last ten years. Repeated measures of body weight at different ages from birth to adulthood of Boer goats are scarce. When available, such data can be used to describe the growth pattern and the meat production potential of goat meat breeds such as the Boer. This paper presents data on estimators of growth curve parameters, plots of average predicted growth curves, plots of residuals on age, and data on goodness of fit statistics of ten non-linear functions fitted to describe the growth curve of Boer goats.

Sexual behavior and seminal characteristics of fertile mature New Zealand White male rabbits of different body weights.

Body weight in different mammalian species influences reproductive potential. The aim of the present study was to determine the relationship of body weight at the time of semen collection with libido, seminal characteristics and number of semen doses for artificial insemination (AI) in New Zealand White mature fertile male rabbits. Data came from 728 semen collections of 14 rabbits, 15-months of age that were sexually experienced with proven semen quality and fertility. Semen collection was performed twice a week with two ejaculates at each collection time and lasted 14 weeks. A second ejaculation was collected at 1-2h after the first. Data from each male from first and second ejaculates from 1 day of semen collection throughout the trial were averaged (n=324) and partial correlation coefficients and regression equations were estimated to describe the relationship of male body weight to ejaculation reaction time and 12 semen and sperm characteristics. As body weight increased there was a linear (P<0.05) increase in reaction time, abnormal sperm with an intact membrane and abnormal sperm with a damaged membrane and a linear (P<0.05) decrease in semen volume, sperm concentration per ejaculate, normal sperm with an intact membrane, number of normal motile sperm with an intact membrane and suitable semen doses for AI. Body weight of the mature male rabbit at semen collection had some influence on libido, semen and sperm characteristics, with a general trend toward a lesser reproduction potential as body weight increases.

Controlled doe exposure as biostimulation of buck rabbits.

Female exposure of males could be a low-cost biostimulation option that benefits AI in commercial rabbit operations by improving buck rabbits reproductive performance. The objective of the study was to evaluate exposure of buck rabbits to females as a biostimulation option to improve reproductive potential. Treatments were: exposure (biostimulated) or not (control) of bucks to does. Bucks were New Zealand White, 15-month-old, sexually experienced and fertile. Experimental design was completely random with nine replications, experimental unit was one buck. Doe exposure was permanent using replacement pubertal does housed in an adjacent wire-mesh cage and changed for new ones every other week. Semen collection lasted 14 weeks (late winter and early spring) twice a week with two ejaculates at each collection. Analyses of variance were under a mixed model: treatments, ejaculate number and season were fixed and rabbit random effects and buck weight at each collection as covariable. Biostimulated bucks showed greater (P<0.05) reproductive potential due to: 7% lesser reaction time (greater libido); and increased semen volume (40%), sperm motility (29%), sperm per ejaculate (31%), normal alive motile sperm (65%) and number of semen doses (64%). Semen characteristics differed by season in control bucks but not in doe exposed bucks (treatment × ejaculate number, P<0.05). Reproductive potential in spring was greater (P<0.05) than in winter in both treatments. Doe exposure is a biostimulation method that improves sexual drive and sperm production and quality of buck rabbits.

Genotype by feeding system interaction in the genetic evaluation of Jersey cattle for milk yield.

Results of studies in dairy cattle about the magnitude of the genotype-environment interaction (GEI) are variable, depending on the definitions of genotype and environment. Therefore, the objective of this study was to determine the magnitude of the interaction of genotype and feeding system (confinement and grazing) in the Mexican genetic evaluation of Jersey cattle for milk yield. The number of lactations and animals in the pedigree used were 5122 and 18 432. An animal model and the MTDFREML program were used to estimate genetic parameters and predict genetic values of the animals. Bivariate analysis was carried out considering the performance of confined and grazing cows as two different traits. Three indicator variables were used to assess GEI: (i) magnitude of the genetic correlation coefficients, (ii) correlation between predicted breeding values and (iii) frequency of coincidence in the ranking of top sires. The magnitude of GEI depended on the choice of the indicator variable. The estimate of genetic correlation coefficient less than unity (0.76; P < 0.05) suggested the presence of biologically important GEI. The differences in phenotypic averages and variances between confinement and grazing systems seem to be the main causes for the genotype by environment interaction detected. However, the correlation coefficient between breeding values from confined and grazing animals (0.96) and the frequency of coincidence between breeding values of common sires within the top 100 in confinement and grazing (0.86) indicated low-to-moderate re-ranking of animals or top sires. In addition, the high correlations between predicted breeding values of Mexican genetic evaluation and the two environments (0.99 and 0.93 for confinement and grazing) indicated that for the two feeding systems, breeding values from national analyses could be safely used.

Influence of supplemental dietary sprouted wheat on reproduction in artificially inseminated doe rabbits.

The sprouted wheat contains great amounts of 6-methoxybenzoxazolinone (6-MBOA) a phenol compound that stimulates reproduction in certain small wild herbivorous mammals. The objective of the present study was to evaluate the effect of dietary sprouted wheat as supplement on reproduction in artificially inseminated doe rabbits. Two-month-old New Zealand White doe rabbits (n = 48) were randomly allocated to one of two treatments: (1) pelleted diet plus sprouted wheat for 6 consecutive days prior to service, (2) pelleted diet only (control). First insemination occurred when does reach 3200g body weight and bred 6 days after parturition across 6 months period during summer and autumn. Records from 41 does completing the experiment accounted for 192 inseminations and 142 kindlings equivalent to 4.6 +/- 0.15 and 3.5 +/- 0.15 litters per doe, respectively. Mean daily intake of sprouted wheat on wet and dry matter bases were 196.1 +/- 7.5 and 75.4 +/- 2.9g, respectively. The number of young born produced per doe during the trail was significantly (P = 0.02) greater in does fed sprouted wheat (28.1 +/- 1.2 versus 23.6 +/ -1.3 control). Does fed sprouted wheat had 0.65 +/- 0.06 receptivity rate at AI over 28 per cent greater (P = 0.001) than does in the control treatment. Sexual receptivity was not influenced by physiological status of does and season (P > 0.05). Diet and season had no effect (P>0.05) on kindling rate. However, physiological status had an effect (P = 0.002) on this variable. Kindling rates for nulliparous, lactating and non-lactating does were 0.95 +/- 0.08, 0.63 +/- 0.04 and 0.78 +/ -0.11, respectively. Sexually receptive does had a greater (P = 0.0001) kindling rate (0.95 +/- 0.05) than non-receptive females (0.63 +/-0.05). Does fed sprouted wheat produced larger (P = 0.02) litters than those in the control group: 7.7 +/- 0.30 and 6.8 +/- 0.32, respectively. There was an effect of season (P = 0.04) on the size of the litter at birth. Largest litters were born during autumn (7.9 +/- 0.37) than during summer (6.6 +/- 0.41). Receptive does had more (P = 0.002) young in the litter (7.9 +/- 0.28) than non-receptive (6.6 +/- 0.35). Feeding sprouted wheat as a source of biological 6-MBOA enhanced sexual receptivity and prolificacy in artificially inseminated doe rabbits bred in summer and autumn.