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Feeding and Rearing of Calves: Nutrition, Milk Feeding, Weaning, and Calf Rearing Methods
Proper feeding and rearing of calves are essential for achieving optimum growth, health, and future productive performance. The nutritional and management practices adopted during the pre-weaning and early post-weaning periods have a direct influence on growth rate, feed efficiency, age at first breeding, and lifetime productivity.
Unlike adult cattle, young calves function physiologically as non-ruminants because the rumen and reticulum are not fully developed at birth. Therefore, special attention must be given to milk feeding, gradual rumen development, and the timely introduction of solid feeds to ensure successful growth and development.
This article discusses the nutritional requirements of calves, the physiological basis of calf feeding, and the commonly practiced methods of calf rearing, including nurse-cow rearing, early weaning, whole-milk feeding, and economical calf-raising systems.
Feeding of Calves
The reticulo-rumen is non-functional in calves; therefore, feeding of calves should be approached as for non-ruminants, as they are not equipped to utilize cellulose efficiently. Calves cannot effectively utilize roughages containing high amounts of cellulose. To encourage the early development of the rumen and reticulum, calves should be fed good-quality legume hay and other suitable roughages.
Calves have a limited capacity to utilize non-protein nitrogen compounds; therefore, substances such as urea should not be included in their ration.
For the same reason, B-complex vitamins are dietary essentials for calves in addition to vitamins A and D.
The esophageal groove exists in the reticulum, connecting the esophagus with the omasum. During nursing and milk feeding, the sides of the groove are raised by reflex action to form a tunnel through which milk passes from the esophagus to the omasum, bypassing the rumen and reticulum. This mechanism continues to function even after considerable development of the rumen if milk feeding is continued.
Different Methods of Calf Rearing
Various calf-rearing systems are practiced throughout the world depending on breed, management conditions, labor availability, and economic considerations. The choice of rearing method influences feed utilization, growth performance, health status, and the overall cost of raising replacement stock.
Nurse-Cow Method
Most draft breeds produce milk that is just sufficient to meet the requirements of their calves, and the calves are allowed to suckle from the dam. However, in the case of crossbred cows that produce more milk than required by the calf, one or two teats may be left for the calf while the remaining milk is harvested to regulate milk production and prevent overfeeding.
In the nurse-cow method, three or four calves are allowed to suckle from one nurse cow. To avoid calf rejection, mucus collected at the time of calving is applied to all calves to be adopted by the nurse cow and the calves are placed before her to lick and dry. This helps prevent calf rejection. The number of calves allotted depends on the milk production level of the nurse cow. The use of a nurse cow is an easy alternative method of raising calves and requires minimal management skills.
Early Weaning and Whole Milk Feeding
In this method, calves are weaned at birth and trained to drink milk from a nipple bottle or pail. The calves should be weighed weekly, and the quantity of milk to be fed should be calculated accordingly.
The recommended feeding schedule is:
| Week of Age | Whole Milk | Legume Hay | Calf Starter |
|---|---|---|---|
| 4th to 7th day | 10% of body weight | ad lib. | ad lib. |
| 2–8th week | 10% of body weight | ad lib. | ad lib. |
| 9th week | 10% of body weight − 2 kg | ad lib. | ad lib. |
| 10th week | 10% of body weight − 4 kg | ad lib. | ad lib. |
If producers are unable to weigh calves according to the schedule, calves may also be fed based on their birth weight.
The recommended schedule is:
| Feeding Category | Birth Weight | Weeks (kg of whole milk/day) | Total Milk | ||||
|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | |||
| 1 | 23–29.5 | 2.25 | 2.5 | 2.7 | 2.25 | 1.8 | 80.0 |
| 2 | 30–33 | 2.5 | 2.7 | 3.0 | 2.7 | 1.8 | 90.0 |
| 3 | 33.5–37.5 | 2.7 | 3.0 | 3.5 | 3.0 | 1.8 | 100.0 |
| 4 | 38–42 | 3.0 | 3.5 | 4.0 | 3.5 | 2.25 | 115.0 |
| 5 | 42.5–46.5 | 3.5 | 4.0 | 4.5 | 3.5 | 2.25 | 125.0 |
| 6 | 47–51 | 4.0 | 4.5 | 5.0 | 4.0 | 2.25 | 140.0 |
| 7 | Above 51.5 | 4.5 | 5.0 | 5.5 | 4.5 | 2.25 | 150.0 |
The general guideline is 8%, 9%, 10%, 8%, and 5% of the birth weight during the 1st, 2nd, 3rd, 4th, and 5th weeks, respectively. Producers who do not have a means of determining the birth weight of calves may classify a calf as small, medium, or large and follow feeding schedule categories 2, 4, and 6, respectively (from the table above).
Economic Raising of Calves with Limited Whole Milk and Calf Starter
Milk is the most expensive component of calf feeding programs. Therefore, several feeding strategies have been developed to reduce rearing costs without adversely affecting growth and health. The use of milk substitutes, skim milk, and properly formulated calf starters can significantly improve the economic efficiency of calf production.
For an economical method of raising calves, whole milk can be partially substituted with skim milk and calf starter. Skim milk is deficient in energy and can be supplemented by incorporating grain mixtures, glucose, dextrin, molasses, vegetable oils, or animal fats. Calves have a limited capacity to utilize sucrose before 4–6 weeks of age, and inclusion before this age may cause diarrhea. Molasses is an inexpensive and readily available source of energy.
A feeding schedule in which skim milk partially replaces whole milk from the 5th day onward and molasses is introduced from the second week may be followed to achieve growth rates similar to those obtained with a whole-milk feeding schedule.
