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Feeding heifers from weaning to breeding: It’s all about consistency

Progressive Dairy Field Editor Jenna Hurty-Person Published on 06 November 2019
Calves at the feedbunk

With heifer raising accounting for roughly 20 percent of total farm expenses, paying close attention to heifer nutrition and management is essential for raising quality replacement animals without adding on unnecessary expenses.

During his presentation, “Managing heifer nutrition from weaning to breeding,” which he gave at the Professional Dairy Conference on Jan. 18 in Red Wing, Minnesota, Trevor DeVries, a professor at the University of Guelph, shared his insight into feeding replacement heifers for maximum production potential. The goal here, he said, should be to accomplish this through good, consistent growth and at a reasonable cost without compromising the heifer’s health or welfare.

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Regardless of the dairy’s methods, heifers should be ready to breed at 12 to 14 months old. Large-breed heifers, like Holsteins, should weigh 350 to 400 kilograms (770 to 880 pounds) at breeding, while smaller breeds should be between 225 and 260 kilograms (495 to 570 pounds) at breeding. To accomplish this, aim for an overall 900-gram (2-pound) average daily gain (ADG) from weaning to breeding for large-breed heifers.

Avoiding the post-weaning growth slump

Calves are never more efficient at converting feed into growth than they are in the first couple months of life, DeVries said. The key here is to maximize that growth, particularly through feeding adequate levels of milk, while setting the calf up to maintain that growth during and after weaning. To do this, consider the method of reducing milk intake, weaning timing, feed type, water and housing management.

DeVries said when calves are fed adequate levels of milk (to maintain equal or greater than 2 pounds per day of growth from milk), they aren’t particularly interested in eating solid foods until they are 6 or 7 weeks old, so weaning age plays a major role in how well calves transition. For example, in a study by DeVries and his students, they compared calves weaned at 6 weeks with calves weaned at 8 weeks to see how well they performed during and after weaning.

They found calves weaned at 8 weeks maintained a similar level of metabolizable energy intake through weaning. This means calves were able to consume and digest enough starter to maintain the same level of nutrition post-weaning as they did pre-weaning. Conversely, calves weaned at 6 weeks had a growth slump, as they were not ready to consume and process enough solid feed to compensate for the loss in milk.

DeVries mentioned similar issues arise when considering the length of weaning. Calves weaned over a period of a week or less struggle to eat enough solid feed to compensate for the loss in milk, which results in a growth slump. However, by weaning less abruptly over a two-week period, calves are encouraged to eat solid feed earlier in life and thus maintain growth.

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Whatever the farm’s weaning program, DeVries said calves should be eating at least 2 kilograms (4.5 pounds) of starter per day by the time they’re fully weaned. When possible, he also encourages producers to avoid adding other stressors at that time. For example, avoid vaccinating, weaning and regrouping calves all in the same week. Space out each of these events whenever possible and keep them on the same starter grain ration immediately post-weaning, as it is a feed they are already familiar with.

Feeding calves from 2 to 4 months old

At this point, DeVries said calves should have about a 1.1-kilogram (2.5-pound) ADG, and 85 percent of their dry matter intake (DMI) should come from concentrated feed. While calves can process fermented feeds, he does not recommend adding them to the ration at this point, as fermented feeds are too high in moisture and calves are not able to eat enough to achieve an appropriate level of dry matter. Instead, he recommends feeding calves a dry TMR that contains concentrate and chopped dry forage such as straw or hay. This TMR can be mixed in large batches and fed throughout the week. Forage particle size should be about 1 inch in length, and it must be well mixed to limit sorting.

When feeding calves at this stage, it is important to feed and push food up regularly to limit sorting and encourage calves to eat several meals a day, DeVries said. Feeding infrequently, where calves have an empty bunk for long periods of time, can cause them to learn to consume the majority of their feed in the space of a few hours. This is called “slug feeding,” which negatively impacts the calf’s digestive system and decreases overall feed efficiency. In addition, once a calf learns this behavior, DeVries’ research has demonstrated it is often ingrained in the animal for the rest of its life.

Feeding calves from 4 to 6 months old

At this age, calves can start to transition to a higher-forage diet and can be introduced to fermented feeds. However, fermented feeds should not constitute a majority of their diet. To keep them on track for breeding at 12 to 14 months, aim for a 0.9- to 1.1-kilogram (2- to 2.5-pound) ADG.

Feeding heifers from 6 months to breeding

By 6 months, heifers are ready to have fermented feeds make up the majority of their total feed intake, while their grain can be decreased to 1 to 1.5 kilograms (2 to 3 pounds) per day. The goal at this stage is to maximize heifer growth without fattening them. On average, they should have a 900-gram (2-pound) ADG.

Targeting nutrient consistency and growth is the big challenge at this stage, DeVries said. An extremely consistent ration is necessary here to promote consistent growth among calves and helps to ensure they are all relatively the same size at breeding. High-forage diets are the industry standard, and they can be economical, but heifers often eat more than they’re predicted. Fillers (e.g., lower quality roughages) can be added, but the more fillers that are added, the more sorting of those diets is observed, resulting in greater variation in what is consumed and less consistent growth across animals.

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Bottom line: Feed consistency is key here. The TMR needs to be consistent from the point of mixing to feed out to consumption. Too often, DeVries said, farms may only feed heifers every second day, leading to inconsistencies in the ration from day to day. Instead, feed heifers daily and push it up regularly. Teaching heifers to slug feed is still a concern at this point, so keeping fresh feed in front of them as much as possible is ideal.

Some farms choose to limit feed heifers at this age to try to target nutrient intakes and growth. DeVries said this can work; however, it comes with some challenges. Limit-fed heifers will have a huge desire to access feed, so the tendency to slug feed is strong. They tend to eat all of their feed in the first few hours after delivery and may have an empty bunk for up to 20 hours a day.

Studies have shown that limit-fed heifers housed on organic bedding may eat their bedding. In addition, they have decreased lying time, may develop oral stereotypies and have increased vocalization, standing without eating and aggressive reaching for feed. Heifers also absolutely cannot be overcrowded in this situation, as all animals will need to be able to access the feedbunk at the same time.

While these target weights and feeding principles are key to developing a quality replacement heifer, every farm must determine exactly how to best accomplish it on their operation. Farms should work with their nutritionist to ensure they’re keeping a fresh, well-balanced and mixed ration in front of their heifers.  end mark

PHOTO: Photo by Mike Dixon.

Jenna Hurty-Person
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