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Genetic traits for a Grazing herd

What is the best way to go about choosing genetics for your grazing herd?
“No single ideal pasture-based cow exists,” says Ted Probert, regional dairy specialist with the University of Missouri Extension.

Probert says a discussion on what genetics to use for a grazing herd really needs to start with a look at what type of system the farm uses. For example, a seasonal dairy’s top priority should be fertility.

Probert says another very important thing to take into consideration is how your milk is marketed. Are you getting a premium for components, or is your primary goal high production of fluid milk?

Body size is another important trait to consider for many pasture-based dairies. “Many pasture-based producers prefer smaller cows that tend to do less damage to grass paddocks, especially during wetter weather,” Probert says. He says many graziers also believe smaller animals have an easier time dealing with heat stress and are typically more mobile than their larger counterparts.

Many traits, such as good udder health, longevity and feet and legs are, of course, important – no matter if the cows are housed in a conventional dairy barn or out on pasture.

Bradley Heins, associate professor of organic dairy production with the University of Minnesota, says when choosing genetics for a grazing herd, producers should focus on profitability more than production. “It’s best to think about it in terms of the amount of milk per acre rather than just production numbers,” he says.

Although there is no type of cow that works best in all pasture-based systems, the cow genetically designed to most efficiently convert forages into milk will usually bring the highest profits.

According to Heins, the top traits to breed for in grazing cows are fertility and longevity, followed by feet and legs. He notes that although fertility is a top priority on seasonal dairies, some grazing operations add a second calving season to reduce the number of cows culled for not being bred on the first try. Heins says this choice simply depends on what works best on an individual farm.

Although many graziers choose crossbreds for their increased fertility, disease resistance and calving ease, some still prefer purebred Holsteins for their milk volume. Heins notes that producers who want to stick with Holsteins on grass-based diets may want to explore New Zealand Friesians, which have been bred over generations for being a smaller animal, efficient on grass and low-input operations, having good body condition and high fertility.

Probert adds that before exploring New Zealand genetics of any breed, producers should be aware that much of the milk in that country is produced into powdered milk, which has led to genetic selection for milk solids content and selection against fluid volume. Farmers who get a premium for components may do well with New Zealand genetics.

Many dairy producers who switch a Holstein herd to a grass-based system have great results crossing to Jerseys, resulting in cows with increased hybrid vigor.

“Traits with low heritability tend to be the traits that can be most easily and quickly improved by heterosis through crossbreeding. Fertility is one of these traits,” says Probert. Moderation of size and increased milk solids content are also usually benefits of this cross.

Heins notes Holstein-Jersey crossbreds tend to have hardier calves, fewer calving problems and increased disease resistance in addition to the increased fertility.

Some graziers use a two-breed system with good results; some incorporate another breed for a three-breed system, often using another breed to improve specific traits in the herd.

“All breeds and their different traits can have their place,” Heins says. Montbeliarde cows tend to have high fat and protein, and good feet and legs. Viking Reds are known for fertility, overall health, low somatic cell count and longevity. Normandy cows carry traits for high fat and protein, compact size, good body conditioning and high fertility.

Operations that do not feed any grain at all may want to consider genetics from New Zealand or France, as dairy cows’ diets tend to be all grass in those countries, Heins says.

Probert says that no matter which crossbreeding system is used, record-keeping is essential. He says, “Good animal identification is important to maintain the proper breed rotation.” He adds, “I do think it is a mistake if producers go wild and mix too many breeds.”

Both Heins and Probert note that there are graziers who successfully use purebred cows as well. “Sometimes it just comes down to personal preference,” Probert says.

Both Probert and Heins recommend the use of A.I. over use of a bull. Heins advises to select bulls of merit that have traits for good fertility, then start narrowing down the selection to what traits are best for your herd.

Probert notes crossbreeding programs are much easier with A.I. because, at any time, the herd will have animals that should be bred to different breeds.

Some dairy producers believe it is more cost-effective to have a bull rather than using A.I. But Probert says, “When the value realized from the use of A.I. (increased genetic gain, improved profitability, increased replacement value, etc.) is properly assessed, cost concerns are seen differently.”

Source: UMN.EDU


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