Reproductive evaluation of Charolais and Charbray bulls on the reproductive efficiency of herds in warm subhumid climate of Veracruz

Resumen

Objective: To correlate the Breeding Soundness Evaluation (BSE) of Charolais and
Charbray bulls in the warm subhumid climate and its effect on the Pregnancy rate and
Calving interval of herds to estimate differences between breeds.
Design/methodology/approach: BSE was carried out on N = 90 Bulls; Charolais (n =33) and Charbray (n = 57), evaluated in situ during the period 2017 to 2019. Bull (age, body condition, libido, and scrotal circumference), Semen (concentration, motility, and volume), Herd (Pregnancy rate and Calving interval) and environment variables (Rainy and Dry season) were analyzed with the one-way ANOVA, Factorial, Multiple regression, and Multivariate analysis.
Results: Charolais and Charbray bulls show similar results in the BSE (p>0.05) in a
warm subhumid climate.
Limitations/implications: Year season (Rainy or Dry) do not affect (p<0.05) the BSE
rating. Libido is associated (p<0.05) with age (R=-0.42), sperm motility (R=0.67), sperm
concentration (R=0.66) and pregnancy rate (R=0.63).

Findings/conclusions: Variables with high association (p<0.05) with pregnancy rate
were libido (R=0.63), motility (R=0.60), sperm concentration (R=0.51) and age (R=-
0.50); variables with high association (p<0.05) with calving interval were: age (R=0.74)
and libido (R=-0.33). Charolais and Charbray bulls show similar reproductive efficiency
in herds under a warm subhumid climate in Veracruz.