A study was conducted to evaluate effects of housing and feeding systems on performance of neo-natal Holstein bull calves. Treatments included individually housed, bottle-fed (n = 5 calves), individually housed, bucket-fed (n = 5 calves), group housed bottle fed (n = 5 pens) and group housed bucket fed (n = 5 pens). Body weights were collected every 7 days and serum and plasma samples were taken on day 0, 28, 55 and 66 for beta-Hydroxybutyrate concentrations. No major differences (P > 0.11) in performance (average daily gain, dry matter intake, and feed efficiency) or β-Hydroxybutyrate (P > 0.14) concentrations were observed between housing and feeding treatments. Likewise, no differences (P > 0.26) were observed in the coefficient of variation for BW or fecal scores or morbidity. Albeit performance wasn’t altered, group housing provides a social environment and bucket feeding lowers the variation of intake amongst the group.

In the present study our objectives were (1) to follow the temporal patterns of testicular LH and FSH receptor (LH-R and FSH-R) concentrations and affinity (Ka) during sexual maturation in bulls, to see if such patterns could explain the control of rapid testicular growth that occurs after 25 weeks of age, when serum gonadotropin concentrations are low; (2) to see if transformation growth factors (TGF- alpha and beta 1, 2 and 3) and interleukins (IL-1 and IL-6) are produced in the developing bovine testis and if their concentrations change during development; (3) to see if the onset of puberty could be hastened by treating bull calves subcutaneously (sc) with 3 mg of bLH (n=6) or 4 mg of bFSH (n=6) once every 2 days, from 4 to 8 weeks after birth. Mean LH-R concentrations decreased from 13 to 25 weeks of age and increased to 56 weeks of age (P<0.05). LH-RKa decreased from 9 to 17 weeks of age, increased to 29 weeks and declined to 33 weeks of age (P<0.05). FSH-R concentrations declined from 17 to 25 weeks of age then increased to 56 weeks of age (P<0.05). FSH-RKa increased from 17 to 25 weeks of age (P<0.05). Testicular TGF-alpha concentrations increased from 13 to 17 weeks of age, decreased to 21 weeks and from 33 to 56 weeks of age (P<0.05). Testicular TGF-beta 1 concentrations decreased from 17 to 21 weeks of age, increased to 25 weeks and decreased from 25 to 29 weeks of age (P<0.05). Testicular TGF-beta 2 concentrations increased from 5 to 17 weeks of age, decreased to 21 weeks, increased to 25 weeks and decreased at 29 weeks of age (P<0.05). Testicular TGF-beta 3 concentrations increased from 13 to 17 weeks of age, decreased to 21 weeks of age and from 25 to 29 weeks of age (P<0.05). Mean testicular IL-1 alpha concentrations decreased from 5 to 9 weeks of age and 13 to 21 weeks of age (P<0.01) while mean testicular IL-1 beta concentrations decreased from 13 to 17 weeks and 29 to 33 weeks of age (P<0.01). Mean IL-1 bioactivity increased from 13 to 17 weeks of age, decreased to 21 weeks, increased to 25 weeks, decreased to 29 weeks and decreased from 33 to 56 weeks of age (P<0.05). Mean testicular IL-6 concentrations decreased (P<0.05) from 9 to 13 weeks of age, increased (P<0.05) to 21 weeks, decreased (P<0.05) to 25 weeks of age, increased (P<0.05) to 29 weeks and decreased (P<0.01) to 56 weeks of age. <p>We concluded that high concentrations of gonadotropin receptors might be critical to initiate postnatal testis growth and support it after 25 weeks of age in the face of low serum gonadotropin concentrations. Testicular TGF-alpha concentrations were higher in calves than adults while concentrations of TGF-beta and IL-1 were higher in the early postnatal period than the peripubertal period. The changes in testicular concentrations of TGFs and ILs led us to suggest a possible local regulatory role in development. Testicular IL-6 concentrations were higher in prepubertal calves than adults. Treatment of bull calves with bFSH from 4 to 8 weeks of age increased testicular growth (SC), hastened the onset of puberty (SC ≥ 28 cm), and enhanced spermatogenesis.

In the present study our objectives were (1) to follow the temporal patterns of testicular LH and FSH receptor (LH-R and FSH-R) concentrations and affinity (Ka) during sexual maturation in bulls, to see if such patterns could explain the control of rapid testicular growth that occurs after 25 weeks of age, when serum gonadotropin concentrations are low; (2) to see if transformation growth factors (TGF- alpha and beta 1, 2 and 3) and interleukins (IL-1 and IL-6) are produced in the developing bovine testis and if their concentrations change during development; (3) to see if the onset of puberty could be hastened by treating bull calves subcutaneously (sc) with 3 mg of bLH (n=6) or 4 mg of bFSH (n=6) once every 2 days, from 4 to 8 weeks after birth. Mean LH-R concentrations decreased from 13 to 25 weeks of age and increased to 56 weeks of age (P<0.05). LH-RKa decreased from 9 to 17 weeks of age, increased to 29 weeks and declined to 33 weeks of age (P<0.05). FSH-R concentrations declined from 17 to 25 weeks of age then increased to 56 weeks of age (P<0.05). FSH-RKa increased from 17 to 25 weeks of age (P<0.05). Testicular TGF-alpha concentrations increased from 13 to 17 weeks of age, decreased to 21 weeks and from 33 to 56 weeks of age (P<0.05). Testicular TGF-beta 1 concentrations decreased from 17 to 21 weeks of age, increased to 25 weeks and decreased from 25 to 29 weeks of age (P<0.05). Testicular TGF-beta 2 concentrations increased from 5 to 17 weeks of age, decreased to 21 weeks, increased to 25 weeks and decreased at 29 weeks of age (P<0.05). Testicular TGF-beta 3 concentrations increased from 13 to 17 weeks of age, decreased to 21 weeks of age and from 25 to 29 weeks of age (P<0.05). Mean testicular IL-1 alpha concentrations decreased from 5 to 9 weeks of age and 13 to 21 weeks of age (P<0.01) while mean testicular IL-1 beta concentrations decreased from 13 to 17 weeks and 29 to 33 weeks of age (P<0.01). Mean IL-1 bioactivity increased from 13 to 17 weeks of age, decreased to 21 weeks, increased to 25 weeks, decreased to 29 weeks and decreased from 33 to 56 weeks of age (P<0.05). Mean testicular IL-6 concentrations decreased (P<0.05) from 9 to 13 weeks of age, increased (P<0.05) to 21 weeks, decreased (P<0.05) to 25 weeks of age, increased (P<0.05) to 29 weeks and decreased (P<0.01) to 56 weeks of age. <p>We concluded that high concentrations of gonadotropin receptors might be critical to initiate postnatal testis growth and support it after 25 weeks of age in the face of low serum gonadotropin concentrations. Testicular TGF-alpha concentrations were higher in calves than adults while concentrations of TGF-beta and IL-1 were higher in the early postnatal period than the peripubertal period. The changes in testicular concentrations of TGFs and ILs led us to suggest a possible local regulatory role in development. Testicular IL-6 concentrations were higher in prepubertal calves than adults. Treatment of bull calves with bFSH from 4 to 8 weeks of age increased testicular growth (SC), hastened the onset of puberty (SC ≥ 28 cm), and enhanced spermatogenesis.

Le terme veaux laitiers se réfère aux veaux mâles et femelles non retenus pour le remplacement et vendus en jeune âge. L’objectif de cette étude était d’évaluer l’association entre les caractéristiques et les pratiques de la ferme et le prix final de veaux laitiers lors de leurs mises en marche dans deux encans québécois. Les éleveurs des fermes d’origine des veaux ont été contactés pour répondre à un questionnaire sur les caractéristiques et les pratiques de leur ferme. L’association entre les caractéristiques et les pratiques de la ferme et le percentile de la médiane du prix des veaux a été évaluée via un modèle multivariable de régression linéaire. Un total de 509 éleveurs a été contacté, 433 ont accepté de participer et 409 questionnaires ont été retenus pour les analyses statistiques. Les fermes ont vendu en médiane deux veaux (entre 1 et 19) et la majorité (82%) était de race Holstein. Leur prix était positivement associé à une production moyenne par vache/an supérieure à 11 000 litres et à la présence sur la ferme de trois travailleurs et plus s’occupant des veaux. Leur prix était négativement associé à la vaccination des vaches pour la diarrhée néonatale, l’absence de désinfection du cordon ombilical des veaux, l’interdiction aux transporteurs d’entrer dans les bâtiments de la ferme et à l’utilisation de ripe de bois comme litière des veaux. Les résultats démontrent que les caractéristiques et les pratiques de la ferme d’origine sont associées au prix des veaux laitiers / The term surplus calf defines the male calves and heifers culled within two weeks of life. The objective of this study was to evaluate the associations between the characteristics and the practice of the dairy farms and the price of surplus calves. Their selling price (CAD/kg) were recorded in two-auction markets between 2019 and 2020. The farms who sold calves during the study were contacted to answer the survey. The possible association between the characteristics and the practices of the farms and the median percentile of surplus calves’ selling price per farm was assessed using a multivariable linear regression model. A total of 509 farmers were contacted, 433 of them have accepted to be enrolled and 409 questionnaires were retained for statistical analysis. The median of the surplus calves sold by the farm was two (between 1 and 19) and the majority were Holstein (82%). The covariates that were positively associated with the median percentile of surplus calves’ selling price per farm were an average milk production per cow/year superior to 11,000 liters and the presence of the farm of three or more workers available to take care of calves. Their selling price was negatively associated with vaccination of cows for neonatal calf diarrhea, no disinfection of the navel of newborn calves, no forbid transporters to entry in the farm’s buildings and use of wood shaving as bedding for surplus calves. The results show the association between the characteristics and practices of farms and the price of surplus calves.