The recent increase in the cost of replacement heifers has renewed the interests of dairy owners and heifer raisers in accelerated heifer raising programs. Decreasing the age at first calving has a significant impact on the number of heifers required to maintain the herd size, as well as decreasing the total costs of raising replacement heifers. Until recently, the newborn calf has been somewhat ignored in accelerated heifer replacement programs. Recent research has brought to light some very important points about the growth and development of young calves and how they fit into the total equation of a good accelerated heifer growth program.
Research has shown that the ideal weight for heifers at first calving is between 1,350 lbs and 1,400 lbs with a minimum wither height of 54.9 inches for Holstein heifers. Baby calves that are fed on whole milk or traditional milk replacer (20% protein, 20% fat) at a rate of 8-10% of their body weight per day will only gain between 0.5 and 1.0 lb per day. Even if these calves had a pre-puberty average daily gain of 1.3 lbs per day, they still would not be able to reach puberty until approximately 14 months of age and would not reach breeding size until approximately 18 months old. This would eliminate the possibility of achieving an age at first calving of 24 months. Heifers experience the most rapid growth rate from birth to 9 months of age. Anything that prevents them from maximizing their growth during this time period will have a very significant effect on their age at first calving as well as their wither height.
It was previously mentioned in Part 1 that if a calf is left on its mother, it will nurse between 6 and 10 times per day and consumes somewhere between 16 and 24% of its body weight per day as milk. A 100 lb calf would then consume 16 to 24 lbs of whole milk per day (1.9 to 2.8 gallons). Whole milk is approximately 12.5% solids so this would translate to about 2 to 3 lbs of dry milk solids per day. Calves consuming this much dry milk solids can gain between 2 and 3 lbs per day. Most milk replacer companies recommend that 1 pound of dry powder be added to 1 gallon of water and that 1 gallon of mixed product be fed to each calf per day. This amount is only 1/3 to ½ the amount that a calf would normally consume if left on its mother. Whole milk is 26% protein and most milk replacers are 20-22% protein. Therefore, not only is the calf on a traditional milk replacer program receiving 1/3 to ½ as much dry milk solids, the dry milk solids contain much less protein than that found in the dry milk solids of whole milk. Perhaps the milk replacers labeled as “Accelerated Formulas” should be renamed “Normal Growth Formulas” since all we are trying to do is obtain the same growth rates as those calves that remain on their mothers.
Most of the accelerated formula milk replacers will contain between 26 and 30% protein and 15 to 20% fat. The protein level is very similar to that of whole milk solids but the fat level is somewhat lower. The purpose of this protein to fat ratio is to promote lean tissue growth rates. Research at the University of Illinois showed that the ratio of lean tissue to body fat was much greater and that the efficiency of gain was much greater in those calves fed the high protein milk replacer. These calves gained weight much faster but also required less dry matter per pound of weight gain. This fact needs to be considered when evaluating the economics of an accelerated calf growth program. This same study fed 3 groups of calves a 26% crude protein, 18% fat milk replacer at a rate of 10 %, 14% or 18% of body weight per day. The corresponding growth rates were 0.79 lbs, 1.55 lbs and 2.25 lbs respectively. I would like to emphasize again that the calves with the greatest growth rates had the highest lean tissue to fat tissue ratio. The higher protein milk replacer promotes more lean tissue gain.
The feeding recommendations vary slightly according to the manufacturer. Most researchers agree that during the first week of life the calf should receive 1.5 to 2% of its body weight in dry milk replacer powder. A good example of this would be to mix 0.9 lbs (14.4 oz) of milk replacer powder in 2.5 quarts of warm water per feeding. This would give a 90 lb calf a total of 1.8 lbs of solids per day or 2% of its body weight. From week 2 to weaning the calf would receive a greater amount of solids per day. An example of this would be to mix 1.3 lbs of milk replacer powder in 3.5 quarts of warm water per feeding. This would result in 2.6 lbs of solids per day in a total volume of 7 quarts. A general recommendation would be to mix the milk replacer at a concentration of 15 to 18% solids. There are many dairies and calf ranches that currently use bottles for feeding milk and milk replacer to their calves. Most of these bottles are two quart size. This makes it impossible to deliver the 3.5 quarts per feeding. However, if one decides to utilize an accelerated milk replacer formula at the recommended feeding rate, the bottle system can still be utilized by increasing the number of feedings per day to three. This increases the amount of labor required, but is actually beneficial to the calf to receive its milk in three feedings instead of two.
One of the main concerns about accelerated milk replacer formulas is that they may cause a nutritional diarrhea. It should be noted that the stools of calves fed these formulas will more than likely be softer than those fed a traditional milk replacer, but nutritional diarrhea has not been observed on any of the many research trials that have been conducted. Obviously, these calves will consume less calf starter when fed larger volumes of high protein milk replacers. This tends to make the stool softer than when more calf starter is consumed. Calf starter should still be offered free choice starting at 3 to 7 days of age even though the amount consumed will be less with an accelerated growth program. Calf starter should be gradually increased as consumption increases with the leftovers being cleaned out on a daily basis.
Even though less starter is consumed, calves can still be weaned at 7 to 8 weeks of age. The recommendation is to discontinue one feeding per day when the calf reaches 6 to 7 weeks of age. The amount of calf starter consumed will rapidly increase. When the calf consumes 2 pounds of calf starter per day for 3 consecutive days, it is ready to be weaned. It is extremely important that the calf have access to free choice fresh water at all times, both while on the milk replacer and after weaning. If the calf raiser does not want to provide free choice water because of freezing problems in the winter or for any other reason, an accelerated growth program such as just described should not be undertaken.
The formulation of a calf starter to be used in an accelerated growth program is also higher in protein than traditional calf starters. Most calf starters on the market today are between 17 and 19 percent protein. It is recommended by most researchers in this area that accelerated calf starter formulas be between 22 and 26 percent protein. It only makes sense that if the calf is on a milk replacer that is 26 to 28 percent protein, the calf starter should also have a higher protein level in order to maintain the same growth rate around the time of weaning. Once weaning is accomplished, the calf should remain on this calf starter without hay for 2 to 4 more weeks. The volume of calf starter consumed can be monitored to make sure that consumption rapidly increases following weaning, to somewhere between 6 and 8 lbs per day. This insures that the calf will continue to maintain its rapid growth rate following weaning, by consuming an increased level of a calf starter with a similar protein level to that of the milk replacer. Once the calf has reached 10 to 12 weeks of age, it can then be introduced to a grower ration that contains 15 to 20 percent good quality alfalfa hay.
Calf starters should be formulated with ingredients that are easily fermented in the developing rumen and/or digested and absorbed in the intestine. Such products may include citrus pulp, beet pulp, small amounts of soyhulls, dried whey, animal protein blends (plasma) and added amino acids such as methionine, lysine, threonine and histidine. It is extremely important that when calculating the amounts of an added medication such as Bovatec®, the nutritionist keeps in mind the fact that these calves are larger in body size than normal and will consume larger amounts of calf starter than what most nutrition programs assume. This could potentially result in the calves consuming toxic levels of specific medications. This should also be kept in mind if medications are added to the milk replacer itself.
The main advantages of an early accelerated growth program are as follows:
- Increased growth rate from birth until weaning.
- Increased lean tissue to fat tissue ratio.
- Increased efficiency of gain.
- Increased parenchymal tissue in the udder (more mammary tissue for potential future milk production).
- Improved immune response resulting in decreased sickness and death.
- Decreased costs due to extra labor and medicine required to treat sick calves.
- Increased chances of heifers reaching puberty early, being bred and calving at less than 24 months of age.
- The program does not have to be altered because of environmental changes in order to fulfill nutritional requirements due to adverse environmental conditions.
In the herds I work with that have incorporated an early accelerated growth program for their calves, I have been impressed with the increase in growth rate and frame size of the calves. However, my biggest surprise was the astounding improvement in the overall health and vigor of the calves. Medicine costs for the treatment of sick calves have decreased by approximately 80 percent and death loss has decreased dramatically to around 1 to 2 percent. It must be emphasized that good management is just as important, if not more, when utilizing this type of program on the farm. Close attention still needs to be paid to good colostrum management and delivery, sanitation of the environment and feeding utensils, and feeding practices. The improved immune response of calves on an accelerated growth milk replacer formula will not compensate for poor management and unsanitary conditions in a calf operation.
Much of the benefit of this type of program will go unnoticed if the heifer does not continue on a well-formulated accelerated growth program as it matures. Continuing on a ration that has been formulated to maximize rumen microbial growth and providing adequate protein nutrition to maximize frame development without causing excessive fat deposition is necessary to accomplish the goal of ideal frame size at an earlier age of first calving. Approximately 63% of dairy operations in the U.S. have an average age at first calving of greater than 24 months. Research has shown that as long as the heifer reaches the desired frame size and weight at calving, there is no detriment to first lactation milk yield regardless of the age at first calving. Calving at an earlier age allows the dairy owner to maintain herd size with fewer replacements, decreases the amount of feed required before the animal enters the herd, and yields a faster return on investment.
Dr. Mike Van Amburgh of Cornell University has estimated that the traditional program of feeding a calf 1 pound of a standard formula milk replacer would cost approximately $67.00 per calf. The accelerated program would cost about $142.00. This would result in an increased cost of $75.00 per calf. My experience has proven that this increased cost is more than returned just in the decreased mortality rates. When considering the other advantages previously listed, this increased investment is returned several fold by the time the heifer enters the herd at first calving. I would like to reemphasize that in order to reap the maximum benefits of an accelerated calf growth program, excellent management needs to be in place. Changing to this type of program will not correct current disease problems or management deficiencies.
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