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oa Agriprobe - The live weight of replacement heifers in commercial dairy herds in the South Western Cape : Elsenburg Journal

Volume 11, Issue 2
  • ISSN : 1810-9799

 

Abstract

Age at first calving for heifers on commercial farms is often later than the recommended 24 months of age. Further, because of a lower live weight at first calving, primiparous cows tend to produce less milk during first lactation than well-reared heifers. Both these factors result in a higher milk production cost. Dairy heifers should be fed to reach a live weight of at least 55% of mature live weight at first breeding (or conception) at 13-15 months of age to calve down below 24 months of age weighing 82% of mature live weight after calving. In this study the live weight of replacement heifers on commercial farms were recorded over a three year period. Heifers weighed varied in age from birth to 36 months of age. The live weight of heifers was regressed on age in days using different growth functions. Observed live weights of heifers according to best fit regression equations were compared to recommendations available from the literature for three dairy breeds. The average daily gain of Holstein, Ayrshire and Jersey heifers from birth to 24 months of age was 0.448, 0.420 and 0.375 kg per day respectively. In comparison to literature information these growth rates are very low. North American literature indicates that the minimum live weight gain of Holstein, Ayrshire and Jersey heifers should be 0.70, 0.55 and 0.40 kg/day respectively. Further studies are needed to determine optimum growth rates for dairy heifers and the effect of poor growth rates on the milk yield of dairy cows under South African conditions.

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/content/agriprob/11/2/EJC157346
2014-01-01
2019-10-22

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