Culling and extended milk feeding

by Sally Colby

Dr. Robert Van Saun, Penn State Extension veterinarian, and Dr. Jud Heinrichs, Penn State professor of dairy science, are well-known among dairy farmers and are often featured at events helping dairy farmers learn how to keep cows healthy in order to increase milk production. “We’re making efficient, quality milk, and now we have to face this very unusual challenge,” said Van Saun, adding that dairymen are being told to reduce production by close to 20%.

Van Saun said dairy farmers can make information-based decisions to avoid dumping milk while minimizing long-term impacts to the herd. The overall goal is to reduce the cost of production, which requires a hard look at the cost of making milk.

“We need to think about reducing farm milk production to minimize the losses or penalties imposed,” said Van Saun. “The other thing to think about, assuming we are staying in the dairy industry, is remaining in a position to recover milk yield when necessary. This means we need to keep cows healthy and efficient, and maintain sufficient cow numbers.”

One option is to reduce cow numbers. “Culling cows will reduce production,” said Van Saun, “but more importantly, reduce feed costs. But think of the impact culling will have when we return to full production.”

The decision process involves deciding which animals to keep. “From a veterinary perspective, I would think about the ‘do not breed’ cows – the chronic mastitis cows, the girls that continue to have high SCCs,” said Van Saun.

Another option is culling poor-performing first lactation cows. Van Saun said culling lame or poor-doing cows makes sense from a welfare standpoint, and if possible, such cows should spend time on pasture to gain weight for market advantage.

Reducing cow numbers often eliminates overcrowding, which removes stressors, and may also lead to increased production, resulting in an additional challenge. Cull cow prices are low, and if there is a high debt load per cow and cows are sold at a low cull cost, the difference comes out of your pocket.

Heinrichs said managing heifer numbers is critical, and that culling heifers will reduce the replacement herd to a reasonable size. Heifers account for a significant portion of total milk production costs. “Keeping dry cows dry a little long frees heifer pens,” he said. “Between lowering age at first calving and good reproductive and health care for the herd, you probably only need seven heifers for every 10 milking cows.” He added that farms that do a good job managing age at first calving can get away with six heifers, which is 30% to 40% fewer heifers than traditionally retained.

For heifer culling decisions, Heinrichs recommended looking at health and genetic potential. “Review cow and bull records and dump calves with respiratory issues,” he said. “Unfortunately, there isn’t a good market for them, and you’re going to get less than you have in, so cull early at weaning or shortly after birth.”

Culling extra animals reduces overcrowding, which can result in higher milk production from the remaining individuals and reduces the number of animals to feed. Feeding higher forage diets helps reduce feed costs, but this requires quality forage. “There isn’t going to be a market for bred heifers for quite a while,” said Heinrichs. “If you aren’t already down to seven for 10, you need to get there.”

Heinrichs said dairy farmers don’t usually consider feeding calves more milk because it isn’t usually economically sensible, but calves can be fed up to 10 to 12 quarts/day. “This can be easily fed for three months and up to four months,” he said. “It’s what a lot of farms have moved to in the past few years.” When calves are fed ad lib milk, they won’t eat starter and won’t have the rumen development they’d have at six- to eight-week weaning. However, the rumen will be well-developed at three- to four-month weaning.

More milk should result in reduced starter costs. However, although calf starter, milk replacer and milk extenders won’t have to be purchased, most calf managers will want to add a coccidiostat such as is standard in starter or milk replacer. “Get the coccidiostat in with a small amount of milk fortifier,” he said, recommending one ounce per calf daily.

Heinrichs said when feeding high levels of milk and no starter for a prolonged period, forage is essential. “The forage can be hay or silage, just relatively fresh,” he said. “Delayed rumen development is possible, and perhaps weaning challenges. The last couple of weeks before weaning, drop their milk and provide some starter or calf grower.”

Keeping calves on milk longer will put stress on calf housing facilities. However, culling calves early and keeping 70% of what was formerly retained should free up space. Watch for cross suckling in group pens, which can result in heifers freshening with blind quarters. Heinrichs recommended removing offenders or using nose weaners.

“Definitely don’t go beyond three to four months at most,” said Heinrichs. “Heifer calves fed milk for longer than usual will have premature mammary development, and watch that calves don’t become overweight.”

Another option is feeding milk to older heifers, but most farms won’t have the facilities for this. If this practice is employed, be sure to allow a break between the calf feeding period and the start of feeding milk to heifers.

“If you’re feeding a TMR to older heifers and have a way to get milk into the TMR, that’s a great way to do it,” said Heinrichs. “Milk is high in protein, fat and sugar. This will eliminate purchasing protein, and you can feed less.” Heinrichs said dairy farmers feeding milk should work with their nutritionist to formulate a TMR for heifers at 40% dry matter. “Eliminate grain, especially protein and most likely the energy component,” he said. “A little bit of forage and milk will be a reasonably good diet. They’ll still need vitamins and minerals.”