Abstract:
Calving rate in communal cattle influences both food security and socio-economics in rural
households. A previous study indicated that scrotal damage caused by ticks could affect the
fertility of communal bulls and reduce the annual calving rate. The objectives of the study
were to investigate the annual calving rate in communal herds by counting calves during herd
visits, perform breeding soundness examinations on bulls and identify adult ticks attached to
their genitalia. This prospective longitudinal survey was based on participatory rural appraisal.
Calving rates were estimated in cows (n = 2398) from 100 randomly selected communal herds
in Moretele over 12 months in 2013, during routine visits by animal health technicians.
Randomly selected bulls (n = 50) from these herds were tested for Brucella abortus, Trichomonas
foetus and Campylobacter fetus subspecies venerealis. The calving rate was 35.86% (0.359). The
mean scrotal circumference was 37.63 ± 3.42 cm. Total sperm motility was 78.73 ± 35.73%;
progressive sperm motility was 27.39 ± 15.81% and non-progressive sperm motility was
51.34 ± 19.92%. Thirty-five of the 38 bulls examined for breeding soundness exhibited severe
scrotal and preputial lesions caused by the adult ticks Amblyomma hebraeum and Hyalomma
rufipes. Tick control methods used included spraying (n = 20), pour-on (n = 11), no control
(n = 1) and various (n = 18). It was concluded that in Moretele genital tick damage had a more
serious impact on the fertility of communal bulls than contagious diseases. Targeted acaricidal
spot treatment of the genitalia of communal bulls to prevent infestation is recommended, as
tick control strategies used by farmers appeared to be inadequate.
