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• 1. [Article] Some effects of diethylstilbestrol on sexual maturation and growth of male calves

  Six experiments were conducted to determine the effects of DES implantation on preweaning performance and sexual maturation of male calves when implanted at various stages of development and different ...

  Citation × Citation Citation Abstract Copy Title: Some effects of diethylstilbestrol on sexual maturation and growth of male calves Author: Patton, Westley R. Six experiments were conducted to determine the effects of DES implantation on preweaning performance and sexual maturation of male calves when implanted at various stages of development and different sites. Calves receiving DES implants in Experiments I and II were implanted at birth, at birth and at about three months of age, or at about three months of age. Some of the calves in Experiment I were left intact until slaughter, while the remainder of the calves in the first two trials were castrated two weeks prior to weaning. Statistical analysis of data from the first trial showed that calves implanted (12 mg.) at birth gained significantly (P < .05) faster to three months of age than did non-implanted calves and held a slight advantage to weaning. An advantage in preweaning performance was not observed for implanted calves in Experiment II. However, there was a significant (P < .01) reduction in the average external diameter of seminiferous tubules in calves receiving two preweaning implants. In both trials, DES treatment caused a delay in development of secondary sex characteristics, such as crest, increased shoulder development and curly hair about the head. In Experiment IIIa there were no differences in preweaning performance and sexual maturation between bull calves implanted at birth and at three months of age and those implanted at three months of age. In yearling bulls with the same treatments (Experiment IIIb) there was a delay in the onset of semen production. Bull calves in Experiment IV received implants at birth, at three months of age, at weaning and after 110 days in the feedlot; the same treatment without the birth implant; or no DES implants. There was a trend toward increased average daily gain with increasing levels of DES. The testes weight was significantly (P < .01) decreased by DES treatment. Furthermore, testes weights of the two DES treatments were significantly (P < .05) different. There was a significant (P < .01) reduction in average external seminiferous tubule diameter with each increase in DES level. Two levels of scrotal DES implants at birth plus ear implants at three months of age were compared to two levels of ear implants at birth plus ear implants at three months of age. In this experiment (Experiment V) scrotal implants did not cause an increase in gain to three months, but there was an advantage over the controls to weaning. Gains were similar for scrotal and ear implants to weaning. At weaning there was a significant (P < .01) reduction in testes weight and average external seminiferous tubule diameter with DES treatment. Experiment VI dealt with bull and steer calves implanted with DES at three different stages of development prior to weaning. At slaughter the inside diameters of the urethras were measured at four locations. Urethra diameter was significantly (P < .01) reduced by castration. DES implants caused a significant (P < .01) increase in the inside diameter of the urethras of steers, but had no effect in bulls. Title: Some effects of diethylstilbestrol on sexual maturation and growth of male calves Author: Patton, Westley R. Six experiments were conducted to determine the effects of DES implantation on preweaning performance and sexual maturation of male calves when implanted at various stages of development and different sites. Calves receiving DES implants in Experiments I and II were implanted at birth, at birth and at about three months of age, or at about three months of age. Some of the calves in Experiment I were left intact until slaughter, while the remainder of the calves in the first two trials were castrated two weeks prior to weaning. Statistical analysis of data from the first trial showed that calves implanted (12 mg.) at birth gained significantly (P < .05) faster to three months of age than did non-implanted calves and held a slight advantage to weaning. An advantage in preweaning performance was not observed for implanted calves in Experiment II. However, there was a significant (P < .01) reduction in the average external diameter of seminiferous tubules in calves receiving two preweaning implants. In both trials, DES treatment caused a delay in development of secondary sex characteristics, such as crest, increased shoulder development and curly hair about the head. In Experiment IIIa there were no differences in preweaning performance and sexual maturation between bull calves implanted at birth and at three months of age and those implanted at three months of age. In yearling bulls with the same treatments (Experiment IIIb) there was a delay in the onset of semen production. Bull calves in Experiment IV received implants at birth, at three months of age, at weaning and after 110 days in the feedlot; the same treatment without the birth implant; or no DES implants. There was a trend toward increased average daily gain with increasing levels of DES. The testes weight was significantly (P < .01) decreased by DES treatment. Furthermore, testes weights of the two DES treatments were significantly (P < .05) different. There was a significant (P < .01) reduction in average external seminiferous tubule diameter with each increase in DES level. Two levels of scrotal DES implants at birth plus ear implants at three months of age were compared to two levels of ear implants at birth plus ear implants at three months of age. In this experiment (Experiment V) scrotal implants did not cause an increase in gain to three months, but there was an advantage over the controls to weaning. Gains were similar for scrotal and ear implants to weaning. At weaning there was a significant (P < .01) reduction in testes weight and average external seminiferous tubule diameter with DES treatment. Experiment VI dealt with bull and steer calves implanted with DES at three different stages of development prior to weaning. At slaughter the inside diameters of the urethras were measured at four locations. Urethra diameter was significantly (P < .01) reduced by castration. DES implants caused a significant (P < .01) increase in the inside diameter of the urethras of steers, but had no effect in bulls. Close

• 2. [Article] Inheritance of maternal antibody concentration in the bovine neonate

  Serum samples were collected between 24 and 48 h of age from 408 Hereford calves of a selection experiment and from 200 Angus, Hereford and Red Poll calves of another experimental population (Germ Plasm ...

  Citation × Citation Citation Abstract Copy Title: Inheritance of maternal antibody concentration in the bovine neonate Author: Muggli, Noelle Elizabeth Serum samples were collected between 24 and 48 h of age from 408 Hereford calves of a selection experiment and from 200 Angus, Hereford and Red Poll calves of another experimental population (Germ Plasm Utilization project). Concentrations of Immunoglobulin G₁ (IgG₁) were determined by single radial immunodiffusion. Breed or selection line of calf and age of dam were the most important factors influencing IgG₁ concentrations (P < .01). In the Germ Plasm Utilization (GPU) herd, Angus calves were highest, Red Polls were intermediate and Herefords were lowest in serum concentrations. Calves from Hereford lines selected for weaning weight, yearling weight or yearling weight and muscling score index were lower in IgG₁ concentration than calves from the randomly selected control line. In both populations immunoglobulin levels in the calf increased as age of dam increased. Calf sex did not affect IgG₁ in either population. In Selection Experiment Herefords, increased calving difficulty was associated with a decrease in calf IgG₁ levels (P < .05). In the GPU population, as birth weight increased IgG₁ levels increased in the Angus, did not change in the Red Polls and decreased in the Herefords (P < .05). Heritabilities of calf serum IgG₁ concentration, estimated from paternal half-sib analysis on a within line or breed basis, were .03 ±-09 and .13 ±.19 in the two populations. In the Selection Experiment Herefords, when the component of variance for selection line was added both to the numerator and denominator of h² the revised estimate was .09 + .09. Heritabilities of maternal effects on IgG₁ concentration were also estimated (by nesting calves within maternal grandsires) on a within line or breed basis. These heritabilities were .23 + .17 and -.07 ± .27 for the Selection Experiment and GPU populations, respectively. In the Selection Experiment population, when the variance component for selection line was added to the numerator and denominator of maternal effects heritability, the estimate was .27 ± .17. Those calves that died had a lower mean IgG₁ concentration than the overall population average (P < .01). Title: Inheritance of maternal antibody concentration in the bovine neonate Author: Muggli, Noelle Elizabeth Serum samples were collected between 24 and 48 h of age from 408 Hereford calves of a selection experiment and from 200 Angus, Hereford and Red Poll calves of another experimental population (Germ Plasm Utilization project). Concentrations of Immunoglobulin G₁ (IgG₁) were determined by single radial immunodiffusion. Breed or selection line of calf and age of dam were the most important factors influencing IgG₁ concentrations (P < .01). In the Germ Plasm Utilization (GPU) herd, Angus calves were highest, Red Polls were intermediate and Herefords were lowest in serum concentrations. Calves from Hereford lines selected for weaning weight, yearling weight or yearling weight and muscling score index were lower in IgG₁ concentration than calves from the randomly selected control line. In both populations immunoglobulin levels in the calf increased as age of dam increased. Calf sex did not affect IgG₁ in either population. In Selection Experiment Herefords, increased calving difficulty was associated with a decrease in calf IgG₁ levels (P < .05). In the GPU population, as birth weight increased IgG₁ levels increased in the Angus, did not change in the Red Polls and decreased in the Herefords (P < .05). Heritabilities of calf serum IgG₁ concentration, estimated from paternal half-sib analysis on a within line or breed basis, were .03 ±-09 and .13 ±.19 in the two populations. In the Selection Experiment Herefords, when the component of variance for selection line was added both to the numerator and denominator of h² the revised estimate was .09 + .09. Heritabilities of maternal effects on IgG₁ concentration were also estimated (by nesting calves within maternal grandsires) on a within line or breed basis. These heritabilities were .23 + .17 and -.07 ± .27 for the Selection Experiment and GPU populations, respectively. In the Selection Experiment population, when the variance component for selection line was added to the numerator and denominator of maternal effects heritability, the estimate was .27 ± .17. Those calves that died had a lower mean IgG₁ concentration than the overall population average (P < .01). Close