Relationship between production characteristics and breeding potential of 25-month old extensively managed Bonsmara bulls

dc.contributor.authorScheepers, S.M. (Susanna Magrietha)
dc.contributor.authorAnnandale, C.H. (Cornelius Henry)
dc.contributor.authorWebb, E.C. (Edward Cottington)
dc.contributor.emailedward.webb@up.ac.zaen_US
dc.date.accessioned2010-09-28T06:31:21Z
dc.date.available2010-09-28T06:31:21Z
dc.date.issued2010
dc.description.abstractThe aim of the study was to determine if the breeding potential of 25-month old Bonsmara beef bulls could be predicted from production characteristics. Forty-one Bonsmara bulls were included in an on-farm performance test (also known as the Phase D growth test) for a period of 180 days. At an average age of 24.7 months the bulls were subjected to a libido test and overall breeding soundness evaluation (OBE). The bulls were categorised into independent breeding potential categories according to the scores they obtained for the measured reproductive traits. The categories included sperm morphology and motility. One-way ANOVA revealed that none of the production traits measured had a significant effect on the different breeding potential categories. A positive correlation (r = 0.33) was recorded between pre-weaning growth rate and percentage morphologically normal sperm, while a negative correlation (r = -0.36) was recorded between total acrosomal- and flagellar sperm defects and pre-weaning growth. A positive correlation was demonstrated between sperm motility and pre-weaning growth (r = 0.36), and a consequent negative correlation (r = -0.38) between the percentage aberrant sperm movement and pre-weaning growth. The correlation between the percentage morphologically normal sperm and percentage progressively moving sperm was r = 0.50, while the correlation between percentage morphologically normal sperm and aberrant and immotile sperm was r = 0.48 for both variables. The number of total defects correlated highly significantly with flagellar and acrosomal defects (r = 0.72 and r = 0.93, respectively) and correlated poorly with the total number of nuclear defects (r = 0.32). These results suggest that total sperm defects were mainly due to acrosomal and flagellar defects, rather than nuclear defects and as the percentage morphologically normal sperm decreased, the motility also decreased. High growth rates before weaning may have a positive effect, while high growth rates after weaning may have a negative effect on the breeding potential of a bull. None of the measured reproductive and production traits had a significant effect on libido score and thus, cannot be used to predict the libido of young extensively maintained bulls.en
dc.identifier.citationScheepers, SM, Annandale, CH & Webb, EC 2010, 'Relationship between production characteristics and breeding potential of 25-month old extensively managed Bonsmara bulls', South African Journal of Animal Science, vol. 40, no. 3, pp. 163-172. [http://www.sasas.co.za/]en
dc.identifier.issn0375-1589
dc.identifier.urihttp://hdl.handle.net/2263/14932
dc.language.isoenen_US
dc.publisherSouth African Society for Animal Scienceen_US
dc.rights© South African Society for Animal Scienceen_US
dc.subjectBonsmara bullsen
dc.subjectBreeding potentialen
dc.subjectLibidoen
dc.subjectProduction parametersen
dc.subjectSemen qualityen
dc.subject.lcshBeef cattle -- Breedingen
dc.subject.lcshBulls -- Performance recordsen
dc.subject.lcshSpermatozoaen
dc.titleRelationship between production characteristics and breeding potential of 25-month old extensively managed Bonsmara bullsen
dc.typeArticleen

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