Relationships of growth hormone gene and milk protein polymorphisms to milk production traits in Simmental cattle

in Journal of Dairy Research (1997), 64(1), 47-56

The importance of milk proteins and the positive effect of administration of growth hormone (GH) on milk production, and the presence in some dairy cattle lines of greater GH concentrations prompted us to ... [more ▼]

The importance of milk proteins and the positive effect of administration of growth hormone (GH) on milk production, and the presence in some dairy cattle lines of greater GH concentrations prompted us to examine the presence of restriction fragment length polymorphism at the GH gene using the restriction enzyme TaqI and to investigate associations between this polymorphism in Simmental cows and bulls, as well as milk protein variants in Simmental cows, and milk production traits. Blood and milk were sampled from 279 Italian Simmental cows and semen was collected from 148 bulls of the same breed. Two fragment bands, denoted A and B, of 6200 and 5200 bp respectively, were examined and three patterns, AA, AB and BB, were found in both animal samples. All variants previously reported in other studies, for kappa, beta, and alpha(s1)-caseins, and beta-lactoglobulin, were found in the cows' samples. For the cows' samples, a BLUP (Best Linear Unbiased Predictor) analysis of results was performed using a REML (Restricted Maximum Likelihood) program and known heritabilities, whereas for bulls we have performed a General Linear Model analysis. The effect of GH gene polymorphism, using TaqI restriction enzyme, on milk production traits was not significant, but bulls of BB pattern had a higher breeding value for milk yield than AA bulls (P < 0.05). For the kappa-casein genotypic effects, cows of AB genotype gave milli with 1.53+/-0.70 g/kg less fat than cows of AA genotype. In addition, breeding values for milk protein content were significantly higher in BB bulls, with 0.87+/-0.32 and 0.71+/-0.34 g/kg more milk protein than AA and AB bulls respectively. Thus, our results revealed a GH gene polymorphism and indicated significant effects of milk protein polymorphisms on milk production traits in the Italian Simmental breed. [less ▲]

Influence of dominance relationships on the estimation of dominance variance with sire-dam subclass effects

in Journal of Animal Science (1997), 75(11), 2885-2891

Two data sets from the USDA Livestock and Range Research Laboratory mere analyzed to study dominance variance and the influence of dominance relationships. The first consisted of 4,155 birth weight (3,884 ... [more ▼]

Two data sets from the USDA Livestock and Range Research Laboratory mere analyzed to study dominance variance and the influence of dominance relationships. The first consisted of 4,155 birth weight (3,884 weaning weight) records of inbred USDA Line 1 Herefords. The second consisted of 8,065 birth weight (7,380 weaning weight) records from a line-cross experiment with five lines. Two models were used. Both included fixed effects of year-sex of calf and age of dam, and covariates for calving date, inbreeding of animal, and inbreeding of dam. For the second set, additional covariates were line composition and heterozygosity coefficients. Random effects were direct and maternal additive genetic, maternal permanent environment, sire-dam subclass, and residual. Model 1 considered sire-dam subclasses unrelated. Model 2 related sire-dam subclasses with a parental dominance relationship matrix. Variance components were estimated using REML. Differences between estimates with Model 1 and 2 were unimportant except for dominance variance. For the first data set, estimates with Model 2 of relative genetic direct and maternal variances, direct-maternal correlation, permanent environment, and dominance variances for birth weight were .35, .13, -.02, .03, and .25, respectively, and they were .39, .11, .04, .06 and .14 for the second data set. For weaning weight, the first data set estimates were .20, .15, -.37, .19, and .11, respectively, and they were .16, .20, -.07, .18, and .18 for the second data set. Changes, decreases and increases, in estimates of dominance variances may be due to increased information from relationships and family types other than full-sibs. The assumption of unrelated sire-dam subclasses might not be appropriate for estimation of dominance variance in populations with many dominance relationships among siredam classes. [less ▲]

Relationships among estimates of inbreeding depression, dominance and additive variance for linear traits in Holsteins

in Genetics, Selection, Evolution [=GSE] (1997), 29(4), 319-326

Estimates of dominance and additive variances were obtained for 14 linear traits. The data included 600 678 first parity records on 14 linear traits in Holsteins. The model included management groups, age ... [more ▼]

Estimates of dominance and additive variances were obtained for 14 linear traits. The data included 600 678 first parity records on 14 linear traits in Holsteins. The model included management groups, age at calving, additive and dominance effects, and regression on inbreeding percentage. The estimate of the dominance variance was 9.8% of the phenotypic variance for body depth: 8.0% for strength, 6.9% for stature, and was less than 5% for the remaining traits. The additive variance ranged from 12.2% for foot angle to 45.3% for stature. No clear relationship was found between the estimates of dominance and additive variance. larger negative estimates of the inbreeding depression were associated with higher estimates of the dominance variance. [less ▲]

Pit-1 gene HinfI RFLP and growth traits in double-muscled Belgian Blue cattle

in Journal of Animal Science (1997), 75(1), 146

Immunological effect of a synthetic growth hormone peptide on IGF-I and IGFBPs in growing pigs

in 4th Intern. Symp. Insulin-like Growth Factors (1997)

Relations entre le polymorphisme de gène Pit-1 et le potentiel génétique de taureaux Holstein

in 2° Carrefour des Productions Animales (1997)

Certification in meat channel

Poster (1997)

TAQ1 restriction fragment length polymorphism for pig growth hormone in pigs.

in Proceedings of the 14th IVPS Congress (1996, July)

Dissociation of increases in plasma insulin-like growth factor I and testosterone during the onset of puberty in bulls

in Journal of Reproduction and Fertility (1996), 106(1), 79-86

The present study was conducted to examine the relationship between plasma concentrations of testosterone, insulin-like growth factor I (IGF-I) and IGF-binding proteins (IGFBPs) during puberty, in male ... [more ▼]

The present study was conducted to examine the relationship between plasma concentrations of testosterone, insulin-like growth factor I (IGF-I) and IGF-binding proteins (IGFBPs) during puberty, in male calves treated with GnRH or testosterone propionate. Twelve male Holstein calves (10 weeks old) were assigned to the control group (n = 6), the GnRH-treated group (n = 3) or the testosterone-treated group (n = 3). For 8 weeks, the GnRH-treated group received a single i.v. injection of GnRH (0.5 mu g kg(-1) body mass) each day while the testosterone-treated group received an i.m. injection of testosterone propionate (0.5 mg kg(-1) body mass) twice a day. The calves were studied until they were 200 days old. Hormone treatments were stopped one month after puberty was reached in the control group. Blood samples were collected every 30 min for 8 h every third day. Hormone concentrations were determined by radioimmunoassay. Western ligand blotting and immunoblotting, using monoclonal antibodies against IGFBP-2, and IGFBP-3, were used to characterize the IGF-binding proteins. In the control group, puberty occurred at about 120 days of age and was associated with an increase in concentrations of testosterone, IGF-I and IGFBP-3 and a decrease in concentration of IGFBP-2. In the GnRH-treated group, plasma testosterone remained low until 8 weeks after establishment of puberty in the control group (4 weeks after the end of treatment). In the testosterone-treated group, testosterone was high during the treatment period and then decreased to prepubertal values when treatment was stopped. Testosterone values increased again to reach postpubertal values 5 weeks after the end of hormone treatment. Nevertheless, independent of testosterone status, the profile of IGF-I and the IGFBPs in the GnRH- and testosterone-treated groups were parallel to that reported for the control group with the transition from prepubertal to adult values at about 120 days of age. In conclusion, concentrations of testosterone, IGF-I and IGFBP-3 increase together, but probably independently, during the onset of puberty in male calves. [less ▲]

Approximation of reliability for multiple-trait animal models with missing data by canonical transformation

in Journal of Dairy Science (1996), 79(2), 317-328

An algorithm for approximation of reliability for multiple traits by multiple diagonalization was modified to support missing data by weighting transformed contributions of records based on the pattern of ... [more ▼]

An algorithm for approximation of reliability for multiple traits by multiple diagonalization was modified to support missing data by weighting transformed contributions of records based on the pattern of missing data. The accuracy of approximation was assessed with simulated and field data by comparing approximate reliabilities with those from direct inversion. Simulated data had several levels of missing data and covariances between traits; correlations were close to those for linear type traits of dairy cattle. Field data were 1) dairy records for milk, fat, and protein yields with 26% of the observations for fat and protein removed and 2) beef records for birth weight, weaning weight, and mean gain after weaning with 43% of observations missing. These files also contained empty fixed effect classes. The algorithm worked best for simulated data, and, when covariances between traits decreased, proportion of missing traits decreased and the number of empty fixed classes decreased. For dairy data, improvement over single-trait reliability occurred only for traits with missing data; for beef data, little or no improvement occurred. The method is useful with multiple diagonalization if the proportion of missing records or number of empty fixed effect classes or covariances between traits is moderate. [less ▲]