Farmers' perception and factors affecting scrotal circumference of beef bulls in South Africa

Abstract

The size of scrotal circumference is highly associated with fertility of a bull, however bulls with under-developed scrotum contributes to unsatisfying performance and low reproduction potential of a bull. The objectives of the study were to: a) identify the perception of farmers on factors affecting scrotal circumference of beef bulls, b) determine the effect of breed and age on scrotal circumference of South African beef bulls during phase D (on-farm), c) determine the interaction effect between breed and age on scrotal circumference of South African beef bulls during phase D (on-farm), d) determine the minimum acceptable scrotal circumference by breed in South African beef bulls during phase D (on-farm). The current study utilized secondary data to address second, third and fourth objectives whereas a questionnaire was used to achieve first objective. Bulls participated into Phase D were aged between 325 and 425 days of age at the start of adaptation period. The test length lasted 90 days with 21 days of adaptation. During the adaptation period, bulls have fed on the same diet similar to the diet they had fed during the trial. Age (days), live weight (kg) and scrotal circumference (cm) were measured on the date of measuring scrotal circumference. During measurement, animals were moved into a crush pen and restrained. First objective was analyzed using frequencies whereas second, third and fourth objectives ware analyzed using Two-way Analysis of Variance (General Linear model) and descriptive statistics. The results indicated farmers’ perception with a high percentage that farmers agree that breed (83.3%), age (83.3%), body weight (75%) and nutrition (66.7%) affect the scrotal circumference of bulls. Furthermore, results showed the high significant difference (P< 0.01) on effect of breed on scrotal circumference, age is also highly significant (P < 0.01) to SC showing the effect, and there is non-significant difference (P> 0.01) on the interaction effect of breed and age on scrotal circumference. Also, presented breeds that are within acceptable standards of scrotal circumference. In conclusion, the perception of farmers is justified by the results of this study when determining the effect of breed and age on scrotal circumference. Furthermore, on conclusions, the scrotal circumference in bulls is affected by breed and age, which implies that the growth of scrotal circumference depends on breed or age of a bull. Also, there is no interaction between breed and age on scrotal circumference, which implies that breed is independent on scrotal circumference and age is independent on scrotal circumference. Lastly, breeds with higher scrotal size are regarded as highly fertile bulls. Findings suggest that bulls with a higher scrotal circumference can be selected looking at breed and age in this study. Findings suggest a scrotal circumference as a dependent factor on breed and age.