Management: The ‘X’ Factor

January 29, 2013 08:17 PM
 
p18 The X Factor

Preliminary results from what is argu-ably the world’s largest controlled crossbreeding study are beginning to dribble in. So far, there are no surprises, says Les Hansen, the Univer-sity of Minnesota dairy geneticist who is leading the effort.

"After four years, more than 4,000 heifer calves have been born within the study; however, fewer than 10% of the anticipated cows for the study have calved and also completed their first lactation," Hansen says.


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The study enrolled 4,185 Holstein virgin heifers and cows from 10 high-producing Minnesota herds in 2008. Forty percent of the females are being bred to Holstein bulls. The remainder are bred to either Montbeliarde or Swedish Red AI bulls to initiate an eventual three-breed rotation.

Eventually, more than 10,000 dairy cows will contribute data to the study over an eight-year span, according to Hansen.

The early, two-year-old milk production results show essentially no difference among the breed groups. All three came in at about 24,000 lb.per cow. Differences did come in pounds of components, however.

The Montbeliarde × Holstein (MxH) and Swedish Red × Holstein (SR×H) had about 4% more pounds of fat (33 lb.) The M×H had 5% more pounds of protein (35 lb.). When the total solids were combined, the M×H had 4% more total solids (67 lb.) than the pure Holsteins and the SR×H had 3% (55 lb.) more.

"The key to crossbreeding is to continue to use top sires from each breed in order to get a valid comparison," Hansen says. The crossbred cattle might not have as much milk in their pedigree as pure Holsteins. "But when you crossbreed, you get the heterosis effect and eliminate any inbreeding effect," he says.

Survival rates through first lactation were no different for Holsteins and M×H. But the SR×H had about 45% fewer animals leaving the herd.

Body condition scores (BCS)were greater for the crossbreds. Holsteins averaged 3.15 BCS compared to 3.62 for the M×H and 3.36 for the SR×H. In an earlier study done with the University of Minnesota campus herd, M×H showed more body condition as well. And they averaged
80 lb. heavier.

"In our campus trial, the Montbeliarde crosses required no additional feed intake than the Holsteins, yet they produced as much milk solids and had higher body condition scores," Hansen says. In other words, they appear to be better at feed conversion to milk and body condition.

Other differences from the field trial thus far:

  • The SR×H had significantly less height than the other cattle.
  • Holsteins had shallower udders with stronger udder cleft as two-year-olds compared to crossbreds.
  • Holsteins had closer rear teat placement and significantly shorter teat length than the M×H.
  • M×H had significantly less set to the hock than Holsteins, and SR×H had more set to the hock than Holsteins.


In general, participating dairy producers have been pleased with the crossbred cattle. One or two, though, have expressed concern about the lack of dairy character with the M×H heifers.

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