Original Research

Scrotal tick damage as a cause of infertility in communal bulls in Moretele, South Africa

Cheryl M.E. McCrindle, Masethe J. Maime, Ester A. Botha, Edward C. Webb, Mario P. Smuts
Journal of the South African Veterinary Association | Vol 90 | a1966 | DOI: https://doi.org/10.4102/jsava.v90i0.1966 | © 2019 Cheryl M.E. McCrindle, Masethe J. Maime, Ester A. Botha, Edward C. Webb, Mario P. Smuts | This work is licensed under CC Attribution 4.0
Submitted: 08 March 2019 | Published: 23 October 2019

About the author(s)

Cheryl M.E. McCrindle, Department of Agriculture and Animal Health, School of Agriculture and Life Sciences, University of South Africa, Pretoria, South Africa
Masethe J. Maime, Department of Animal and Wildlife Sciences, Faculty of Agricultural and Natural Sciences, University of Pretoria, Pretoria, South Africa
Ester A. Botha, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
Edward C. Webb, Department of Animal and Wildlife Sciences, Faculty of Agricultural and Natural Sciences, University of Pretoria, Pretoria, South Africa
Mario P. Smuts, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa


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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.

Keywords

bull fertility; communal farming systems; Hyalomma rufipes; Amblyomma hebraeum; calving rate; Moretele; North West Province

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