Body measurements as selection criteria for growth in South African hereford cattle

E Van Marle-Köster,J Van Der Westhuizen,B E Mostert

doi:10.5194/aab-43-5-2000

E Van Marle-Köster, J Van Der Westhuizen + Show 1 more

Open Access

https://doi.org/10.5194/aab-43-5-2000

Copy DOI

Abstract

Abstract. Birth weight (BW), weaning weight (WW), yearling weight (YW) and seven body measurements (cannon bone length at birth (CB); hip height at weaning (HHW); hip height at yearling (HHY); body length at weaning (BLW); body length at yearling (BLY); scrotum circumference at weaning (SCW) and scrotum circumference at yearling (SCY), measured in a Hereford stud (1497 animals) over a period of 19 years, were used in estimating genetic (co)variances, heritabilities and correlations. Nine different multitrait animal model evaluations were carried out whereby (co)variance components were estimated using the REML VCE 3.0 package. Estimates from different evaluations were pooled, weighing each estimate by the inverse of the sampling variance to calculate weighted mean variance ratios among the different traits. Generally, structural traits tended to have lower heritability estimates (CB = 0.24; HHW = 0.28; HHY = 0.33; BLW = 0.22; BLY= 0.14 ) when compared with literature values , while estimates for production traits compared well with estimates reported for the South African National Evaluation. Weights and linear body measurements were positively correlated (0.4−0.9). Negative correlations were found for scrotum, circumference at weaning and yearling with BW and CB respectively. SCW and BW: −0.54; SCY and BW: −0.65; SCW and CB: −0.66; SCY and CB: −.58. It is concluded that CB could serve as an early indicator of mature size and weights at different ages.

Highlights

Herefords in South Africa increased in size from an average Frame Score 3 (119.38 cm) to an average of 5 (129.54 cm) at 15 months of age over a period of approximately 15 years (Hereford Breeders Society of Southern Africa, 1997)
MARLE-KÖSTER et al.: Body measurements as selection criteria for growth in South African hereford cattle were grouped according to the number born per month over the 19 years namely; January to April, May to August and September to December
Preweaning growth had no detrimental effect on SC, but there is reason for concern if selection is based on growth end-points

Summary

Introduction

Herefords in South Africa increased in size from an average Frame Score 3 (119.38 cm) to an average of 5 (129.54 cm) at 15 months of age over a period of approximately 15 years (Hereford Breeders Society of Southern Africa, 1997). Body measurements have been of recurring interest in beef cattle selection and breeding programmes Measurements such as hip height or wither height were used to study skeletal development. It is of interest to evaluate the relationship of scrotal circumference, as indicator of reproduction, with other linear body measurements and weights. Hereford breeders are taking body measurements and weights at different ages and production stadia. It should be established which measurements provide the most accurate and best Information for effective selection.

Objectives

Methods

Conclusion