Rumen Development: Starting Calves on Dry Feed

Calf-raising is an essential part of a dairy operation. The primary goals during the early weeks of a calf's life are to develop a strong immune system and to stimulate rumen development. If these goals are met, low stress weaning at six weeks of age or less can occur. A USDA survey showed that over 58% of producers wean their calves at 6 to 8 weeks of age with over 15% waiting until 12 weeks of age or later.

The motivation for early weaning is simple: every day it takes to wean your calves costs you money. Weaning earlier means lower feed and labor costs for the pre-weaning period, fewer digestive upsets for calves on dry feed and an increased ability to digest the more inexpensive concentrates and forages at a younger age. Depending on the diet and its health, a calf can be safely weaned at four weeks of age.

The rumen of the calf is basically undeveloped at birth. Intake and digestion of dry feed results in the production of volatile fatty acids which promote rumen development. The carbohydrates in grains are a much better source of these end products than is hay. It is these end products of digestion which are responsible for rumen development rather than the physical bulk provided by forage. Feeding hay prior to weaning can slow down both rumen development and calf growth.

Effective fiber, however, must still be provided. These requirements can be met in young calves without feeding conventional forms of forage. A commercial starter can provide the necessary fiber through the addition of higher fiber grains and grain by-products.

Young calves have a high energy requirement and a low dry matter intake. Feeding hay, even good quality hay, will lower the energy intake of calves.

Suggestions to Promote Early Rumen Development

1. Offer high-quality calf starter from three days of age. Change it daily to keep it fresh. Saliva contamination, flies and mold growth will all reduce starter intake. Because only small quantities of starter are needed, it may be more advantageous to purchase a commercially prepared product. The freshness, texture and palatability of these feeds will help promote intake.
2. Promote early dry feed intake. Place a small amount of starter in the calf's mouth after milk feeding, or place a small amount in the bucket after the calf has finished its milk.
3. Offer clean, fresh water daily starting at one week of age. Water offered to calves should be of the same quality as drunk by humans. The availability of fresh quality water for calves is well recognized to improve starter intake over calves without free choice access to water.
4. Wean the calf when it consumes 0.7 kg of starter per day for two consecutive days. This level usually occurs at four to six weeks of age.
5. Introduce forages after the calf has reached six weeks of age and is consuming more than 0.9 kg of grain per day. Silages and pasture are not recommended for this age group due to the high moisture content.

The feeding of hay preweaning is probably the single topic most likely to generate heated discussion and there are many variations of the above guidelines. Consider the University of Manitoba dairy calf program. Calves are weaned at five weeks of age. They receive 0.25 kg of chopped hay per day from four weeks to three months of age. At three months of age they are moved into group pens where forage is available free choice.

The important thing to remember is that if early weaning is your goal, forages are best kept out of, or certainly limited, in preweaning diets.

By Karen Dupchak, Farm Production Extension, Animal Nutritionist
Manitoba Agriculture Food, and Rural Initiatives

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Rumen Development: Starting Calves on Dry Feed

Suggestions to Promote Early Rumen Development