BEEF PRODUCTION AS ADJUVANT IN DAIRY OPERATIONS.

Beef production from dairy herds is possible through culled cows while bull calves can be reared for veal or beef production. This potential is however often not exploited, probably because of its relatively small contribution to overall farm income. In South Africa beef contribution from dairy herds is estimated to be about 10% of the total beef production. One reason is the small national dairy vs. beef herd and secondly that large Jersey populations are popular in pasture-based areas. For Jersey farmers, little income is generated from rearing bull calves, because of low growth rate of culled cows and steers compared to other dairy or beef breeds. Beef production output of Jersey herds could be improved using beef or dual-purpose breed sires on part of the dairy herd. To do this, all progeny from crossbreeding must be culled. This practice can only be applied in stable dairy herds maintaining low culling rates among cows and successful heifer rearing to first calving. To further investigate the potential, the authors cited embarked on an extensive crossbreeding project which included the use of the Belgian Blue and Limousin sires on Jersey cows and Belgian Blue sires on Holstein cows under commercial farming conditions. The results of three other studies with Fleckvieh sires on Holstein and Jersey cows were also available. Pure- and crossbred bull calves in these studies were compared in both veal and beef production systems.   

Initially, Jersey cows in a pasture-based system were serviced by Belgian-Blue and Limousin sires. Crossbred bull and heifer calves were reared on pasture to 24 months of age and growth rate parameters compared to Jersey steers. At marketing, the live weight of crossbreds was heavier than Jersey steers, although lower than expected because of poor pasture quality and utilization.

Further crossbreeding studies included Holstein and Jersey cows serviced by either purebred sires or Fleckvieh sires. Pure- and crossbred bull calves were reared intensively as veal to live weights of approximately 200 kg to ensure a carcass weight not exceeding 100 kg. Another group of bull calves were reared as beef to 21 months of age on dryland pasture. As expected, the daily live weight gain was higher in crossbred bull calves and steers compared to Jersey calves and steers, while not differing between Fleckvieh x Holstein and Holstein bull calves and steers.

Conclusions and recommendations by the authors: Results from all the studies demonstrate the potential for a higher beef income from crossbred veal calves and steers, specifically when compared to pure Jersey calves. Relatively few calving down problems were observed using beef sires on older cows. Using a dual-purpose breed like the Fleckvieh on Holstein cows did not improve beef income compared to Holstein steers although a later age at marketing may result in improved beef income. 

It is suggested that farmers should use sexed semen on heifers and high genetic merit cows to generate replacement heifers and surplus heifers for sale, while beef sires are used on the rest of the herd for beef production. However, rearing too many replacement heifers can be costly because an established market for heifers may be lacking. Similarly, using too many beef-on-dairy bulls may result in too few replacement heifers to sustain the dairy herd. Therefore, it is recommended that the number of dairy cows used for crossbreeding should not exceed 20% of the herd, otherwise the genetic improvement of the herd may be compromised as a result of the reduction of the number of replacement heifers from dairy sires.