Rearing Replacement Heifers: Birth to Weaning

Vinicius Moreira  |  7/28/2005 1:23:08 AM

Kasimu H. Ingawa, Instructor, Department of Dairy Science

Introduction

It has been estimated that the cost of raising or purchasing replacement heifers is between 15 and 20 percent of total milk production costs, ranking second only to feeding expenses. The future productivity of the herd clearly depends on a supply of healthy and genetically superior replacements. In the course of heifer development, perhaps no phase has more uncertainty or economic importance than the period from birth to weaning. During this period, the calf is more susceptible to many diseases, more sensitive to environmental stresses, and more responsive to management changes. Consequently, labor, feed and general management inputs are all high. Therefore, it is necessary to frequently evaluate and eliminate problems in the calf management program. The goals of this paper are to provide an overview of calf management from birth to weaning and to identify strategies for maximizing overall profitability.

Calving

Effective calf management actually begins late in pregnancy, because the dam’s health and nutritional status can clearly influence the calf’s health at birth. Thus, the cow must be kept in good health and have adequate nutrition throughout the gestation period. Calf survival also depends upon activities at or near parturition. It is important to maintain a clean, dry maternity area where frequent observation can be carried out as calving approaches. As soon as labor begins, the animal should be closely watched in case it becomes necessary to provide assistance. Heifers usually have more calving problems than older cows, therefore, special attention should be given to these animals.

The calf should begin breathing immediately upon hitting the ground. If not, a clean spoon handle or finger can be inserted about two inches up the nostrils and rotated gently to stimulate breathing. Make sure that the nostrils are free of mucus or other blockages. Avoid pounding the calf’s chest or shaking it head-down by the hindlegs. If the cow does not immediately dry her calf, dry it off with a clean towel. The calf’s umbilical cord is an open channel for disease-causing organisms and should be thoroughly disinfected with 7% iodine solution immediately after calving. Iodine will disinfect the navel stump and cause shrinking of the blood vessels to minimize chances of infection. Some reports have also suggested tying off the umbilical cord about two inches from the body with alcohol-saturated string and then removing the excess cord. The newborn calf should try to stand within 20 minutes and attempt to nurse within two hours of birth.

Colostrum and First Feeding

Colostrum is the first milk secreted at parturition. It is fortified with protein, minerals, and vitamins. The protein is mostly in the form of antibodies ( immunoglobulins) which help the calf to fight diseases. Older cows and those dried off longer generally have higher levels of immunoglobulins in their colostrum. A high quality colostrum appears thick, rich, and creamy. A pinkish color or any other unusual appearance may indicate an abnormal condition. Immunoglobulin levels are highest in the first milk drawn after calving and decrease with each subsequent milking. Immunoglobulin levels drop to an ineffective level by the fourth milking. Milking the cow prior to calving may reduce the concentrations of immunoglobulins in the colostrum.

At birth, the calf is not yet producing its own antibodies and must consume colostral immunoglobulins for protection against disease. This transfer of antibodies from the cow to her calf is called passive immunity and lasts for about eight weeks when the calf starts producing its own antibodies. Immunoglobulin absorption in the calf’s intestine is highest in the first few hours after birth and declines to very low levels by the second day of life. Consequently, colostrum must be fed to the newborn calf a soon as possible after birth, preferably within the first half-hour, to obtain maximum absorption of immunoglobulins. One half gallon of colostrum (or 4 to 5% of birth weight) should be fed within 30 minutes of birth and this should be repeated 6 to 12 hours later. When calves are too weak to drink, colostrum should be given using a stomach tube (esophogeal feeder). Colostrum feeding should be continued for an additional two or three days. The cow and calf can be left together for the first day. The time with the calf may help stimulate uterine contractions and expulsion of the afterbirth and fluids. However, this practice increases the risk of mastitis and should be restricted to less than 24 hours. Also, to guarantee that some colostrum is consumed by the calf, a small amount should be bottle-fed. Freeze any extra colostrum, especially from older cows or those with high quality colostrum. Thaw frozen colostrum slowly as high temperatures will destroy the immunoglobulins.

Housing and Liquid Feeding

One clear goal of a well-designed calf management program is to minimize exposure of the calves to infectious pathogens. Calves should be housed in a clean, dry and draft free environment. If group housing is used, close attention should be paid to cleaning and sanititation. Disease can spread fast when calves are housed in groups. A calf should be isolated from the group, as soon as it is observed to be sick. However, individual housing, such as hutches, is more effective in maintaining calf health and controlling the spread of disease. It is critical to thoroughly clean and disinfect the housing area between groups of calves. The type of bedding material used must be easily replaced and (or) disinfected.

The liquid feed for a preweaned calf is clearly the most expensive part of the calf feeding program and offers the greatest potential for improving economic efficiency. Sources of liquid feed include milk replacer, saleable and waste milk, and excess colostrum. Saleable milk is expensive and the feasibility of using this source should be throughly examined. Milk replacer should contain at least 20% CP (from milk protein sources) and 15 to 20% fat. Whole milk or milk replacer should be fed at about 8% of birth weight daily. Calves can be fed once daily but should be checked for health one additional time each day. Milk replacers should be prepared and fed according to the manufacturer’s directions. Excess colostrum has more solids than whole milk and will require diluting with one part water per 2 or 3 parts of colostrum before feeding. Whatever the feeding method or feed source used, all feeding utensils and other equipment must be properly cleaned and sanitized after each use. Drastic changes in feeding schedule, temperature of liquid feed or the amount offered should be avoided.

Weaning and Rumen Development

Until weaning actually occurs, the primary goal of starter feeding should be to stimulate the development of the calf’s rumen as soon as possible, so that expensive liquid feed can be eliminated. Although the majority of dairymen wean calves between 5 and 8 weeks of age, many farmers routinely wean as early as four weeks of age. Beginning within the first week of life, the calf should be aggressively encouraged to eat calf starter. The calf starter should contain 20% protein from high quality protein sources, such as soybean meal. Good starters will be coarse textured and have palatable feeds such as molasses and oats. The starter should also contain a broad-spectrum antibiotic (Aureomycin, Terramycin, 50 g/ton) and a coccidiostat (Deccox, 45 g/ton). When the calf is about 6 to 7 weeks old, it can be offered some high quality grass hay. It is well-accepted that it is the fermentation of grain, and not roughage/bulk, that stimulates rumen development. Feeding hay any sooner will only reduce the calf’s consumption of grain.

Summary and Applications

In replacement rearing, no phase has greater potential for decreasing production costs and increasing profitability than the period prior to weaning. No less attention should be given to the care and nutrition of the pre-calving cow than is given to her calf. Calves should be given only the highest quality liquid feeds and the importance of effective cleaning and sanitation cannot be overstated. Finally, it must be kept in mind that the primary goal of the starter feeding program is to stimulate rumen development and eliminate liquid feeding as soon as possible.

Rate This Article:

Have a question or comment about the information on this page?

Innovate . Educate . Improve Lives

The LSU AgCenter and the LSU College of Agriculture

Top