Disease control, adequate nutrient supply and rumen development are the major needs of the calf.
Dry cow nutrition is related to calving problems, thriftiness of the calf at birth, and colostrum quality.
Colostrum is the primary source of immunoglobulins (Ig or antibodies) needed by the calf to fight off infections. Immunoglobulin absorption in the calf’s intestine is highest immediately after birth and declines rapidly.
Milk, milk replacer, or fermented colostrum should be fed up until weaning at 4-8 weeks of age. Calf starter and water should also be offered free-choice. Calves should be weaned once they consume 2 pounds (0.91 kg) of calf starter for three consecutive days. Hay should not be offered until after 6 weeks of age.
Calf managers need to provide the immunoglobulins and nutritional support necessary to not only keep calves alive but also to achieve growth as soon as possible after they are born. A reasonable management goal should be to have less than 5% mortality in the calf barn. Most calves will lose some weight during their first two weeks of life. However, by 6 weeks of age, calves should have at least achieved an average daily gain (ADG) of 1 pound (0.45 kg) of body weight per day (42 pounds (19 kg)).
Prenatal Calf Nutrition
The mother's nutrition during the dry period will affect the calf. Watch the energy content of the diet during late lactation and the far-off dry period. Avoid excessive fattening. Fatter cows (>3.75 BCS) have more calving problems which can lead to calf deaths. On the other hand, dry cows that are underfed will prioritize nutrients to the growing calf inside of them. This can cause calving problems, especially in first-calf heifers, with a normal size calf coming out of an inadequately sized cow.
Selenium comes to the calf through the cow's placenta. Supplement the dry cow with adequate selenium (0.14 mg/lb, 0.3 ppm). Selenium deficiency can result in early births, weak calves at birth, and stillbirths. Selenium is needed to prevent white muscle disease. Sometimes the signs of this disease are obvious with calves showing stiff joints. The disease can lead to death. Often, however, a sign of selenium deficiency can just be general unthriftiness.
Dry cow nutrition affects colostrum quality. Colostrum is low in vitamin E unless the cow is supplemented. Normally, it is recommended that 1000 IU/day of Vitamin E be supplemented during the dry period. Without adequate vitamin E from colostrum, the calf's immune system will suffer and the calf may show signs of white muscle disease. Also, a Canadian research study showed that when dry cows do not get enough protein, their calves absorb less immunoglobulins from their colostrum. 12-13% protein (containing 30-35% UIP) in the far-off dry cow diet and 14-15% protein (containing 35-40% UIP) in the prefresh diet fed the last 3 weeks before calving is recommended. Finally, vaccinate cows during the dry period for E-coli, rota-coronavirus and clostridial enterotoxemia. This will increase the ability of colostrum to prevent calves from scouring during the first few weeks of life.
The Newborn Calf
Colostrum is the cow's first milk after calving. It is just the first day's milk. Milk produced on Day 2 and Day 3 after calving is called transition milk. Colostrum is the primary source of immunoglobulins (also called Ig or antibodies) needed by the calf to fight off infections. Colostrum also contains higher levels of fat, solids, protein, and vitamins needed to provide the calf with good nutrition right at the start of life.
Calves are born with almost no immunoglobulins in their systems and they must receive immunoglobulins from colostrum. The ability of the calf's intestine to absorb immunoglobulins is high at birth but declines rapidly. By 24 hours after birth there is little immunoglobulin absorption. The result is a race to get enough Ig into the calf before her intestine can't absorb anymore. There is also a race to get Ig into the calf before bacteria do. If bacteria reach absorptive sites in the intestine before Ig, they will be taken in and infect the calf. These bacteria primarily come from manure so cleanliness at calving time is important. For cleanliness, it is recommended that the calf be taken away from the dam as soon as possible (no more than an hour). Also, dip navels in iodine solution (7% tincture) as soon as possible.
In a recent USDA study, blood samples were taken from 2177 heifer calves from commercial farms in 28 states between one and two days of age. It was found that 40% of the calves didn't have the recommended IgG level of 1000 mg/dl and 25% of calves were below 620 mg/dl, greatly increasing the risk of disease. By 8 weeks of age, 96% of the calves that had over 1000 mg/dl IgG at one to two days of age were still alive. Less than 92% of the calves having less than 1000 mg/dl IgG survived to 8 weeks.
Colostrum quality can vary. Research at the University of Tennesee with Jersey cows showed that the amount of IgG in colostrum could range from 28 to 115 g/l. This difference is great enough to impact calf immunity. Older cows usually produce higher quality colostrum than first-calf heifers because they have been exposed to more diseases over their lifetime and their Ig transport mechanisms may also benefit from maturity. Cows may also produce farm-specific immunoglobulins, making the colostrum produced on the farm more effective in fighting that farm's own particular disease organisms. Short dry period length may reduce the amount of Ig in colostrum. Ig are also diluted if the cow produces a large volume of colostrum, hence, the “18-lb rule”. If a cow makes more than 18 lbs (8.2 kg) of colostrum, don't use it for a newborn calf. Finally, remember that if the cow is milked or leaks a lot of milk before calving, her colostrum is likely to have a lower level of immunoglobulins. A colostrometer can be used to measure the specific gravity of colostrum and provide an estimate of colostrum quality. This is not a perfect measurement but it is recommended because it is simple and it is better than no colostrum evaluation at all. The goal should be to feed only good colostrum (>50 g/l IgG) to calves. Good colostrum can be refrigerated for one week and can be frozen for up to a year and thawed in warm water or on “low” in the microwave. Don't use mastitic colostrum or colostrum with blood in it. Use colostral supplements only when good quality colostrum is unavailable. These supplements are not as good as colostrum but are better than no colostrum at all.
Feed at least 3 quarts (2.8 l) of colostrum within 1 hour of birth and again 12 h later. Do not let the calf simply suckle the cow because then the volume of colostrum consumed will be unknown. Try to use a nipple-bottle. Use an esophageal feeder if you cannot get the needed colostrum into the calf with a bottle within 1 hour of birth. It is important to remember that this method places milk into the rumen rather than the intestine, slowing absorption somewhat. For this reason, try to get 25% more colostrum than what is needed with a nipple-bottle into the calf with the esophageal feeder. It is important to use esophageal feeders correctly. Continue to feed lower quality colostrum or transition milk for 2-3 days after birth (2 quarts (1.89 l), twice daily). Even though the immunoglobulins won't be absorbed after 24 hours, the colostrum or transition milk will help to protect the intestine from infection. The higher protein and fat in the colostrum is also useful for the calf during this period of stress.
Four Days of Age To Weaning
Goals of calf raisers at this time should be to provide an adequate supply of nutrients to the calf for maintenance and growth while at the same time developing the rumen and encouraging the calf to gradually get most of its supply of nutrients from grain rather than milk. Another goal is to prevent scours because they can reduce growth rates and possibly lead to death.
Calf starter and milk (whole milk, fermented colostrum or milk replacer) should be fed beginning at 4 days of age. On traditional whole milk or milk replacer programs, studies have found that in the first six weeks of a calf's life, 75% of the variation in weight gain can be attributed to calf starter intake.
Whole Milk, Fermented Colostrum or Milk Replacer
Calves should be fed milk, milk replacer, or fermented colostrum from 4 days of age until weaning sometime between four and eight weeks of age. Whole milk should be fed at 8-12% of body weight, preferably split between two feedings. Commonly, this means feeding 2 quarts (1.89 l) of milk twice per day. Most milk replacers are recommended to be fed at 8 oz.(0.23 kg) /2 quarts (1.89 l) warm water (110 o F (43 o C)) twice per day. Fermented colostrum also can be fed after diluting it with water. Feed 2 quarts (1.89 l) of fermented colostrum plus water (75% colostrum and 25% water) twice per day. Sanitize feeding equipment between feedings.
Modern milk replacers can provide the same quality for the calf as milk, but at less cost. Fifty pounds of milk replacer can replace 400 pounds (182 kg) of milk. This is approximately the amount needed to raise one calf. There are significant differences in both price and quality of today's milk replacers. Calf raisers should be knowledgeable about these differences and read the tag before making purchasing decisions. The ingredients will be listed on the tag in descending order based on their level of inclusion in the milk replacer.
Milk replacers generally contain between 18 and 22% protein, with 20% being the most common. All-milk protein milk replacers are generally considered the best. Examples of milk proteins include: dried whey protein concentrate, dried whey, dried whey product, skim milk, casein, and sodium or calcium caseniate. Most milk replacer companies are now using whey proteins rather than skim milk or casein protein. Both are good sources of protein but whey will not clot when it is mixed with rennet. For this reason, clot formation is no longer an indication of milk replacer quality as it used to be. Some milk replacer companies now include blood proteins in their milk replacers. Quality blood proteins have been shown to perform as well as milk protein. Other protein sources in milk replacers which are not regarded to be as good as milk protein are: soy protein isolate, protein modified soy flour, soy protein concentrate, soy flour, and modified wheat protein. Plant proteins are generally less expensive, less digestible, and do not provide as good of a blend of amino acids as milk proteins. As a result, the calf can not convert plant proteins into muscle and bone as easily. Milk replacers containing plant proteins usually have crude fiber levels greater than 0.2%.
Fat levels of milk replacer range from 10 to 22% with the most common being 20%. Fat provides most of the energy in milk replacer. So, the higher the fat content, the higher the energy and generally, the higher the value. High fat levels in the milk replacer may be especially needed during cold weather. An alternative to feeding higher fat during cold weather would be to offer 25-50% more milk replacer in a third feeding.
Vitamin and mineral levels of milk replacers should be similar or greater than that in whole milk. Vitamin E helps to boost the calf's level of immunity by stimulating antibody formation. Studies have proven that Vitamin E can decrease scouring in calves. It is generally recommended that calves receive a minimum of 100 IU of supplemental vitamin E each day in their milk replacer.
Good calf raisers do everything they can to stimulate calves to take one more bite of grain. A palatable calf starter should be offered to the calf by 4 days of age. Calf starter should be kept fresh. Don't offer a lot more than the calf is expected to eat in a day. Take away day-old starter and start with fresh starter twice each day.
Most commercial calf starters on the market contain a blend of pellets, crimped oats, and flaked corn for texture. They also have molasses coating the outside of the ingredients. Researchers have found that calves generally prefer the textured, high molasses feeds and calves eat more of these starters at an earlier age. Other, less-expensive calf starters in the form of pellets are on the market. Evaluate all starters based on nutrient content and intake research. Calf starters generally contain between 16% and 24% protein. A high-quality calf starter should contain at least 20% CP and 70% TDN (As-Fed). Calf starters that contain a blend of amino acids similar to that needed for the production of muscle and bone should enhance gain in young calves.
Rumen development is dependent upon the production of volatile fatty acids, particularly butyrate and propionate, making grain consumption very important. Research has shown that it is these volatile fatty acids which cause the rumen papillae to grow. Rumen papillae absorb volatile fatty acids out of the calf's rumen to be used as a source of energy for the calf. More of these volatile fatty acids will be generated from grain than from hay. For this reason, it is recommended that hay not be offered until the calf is weaned or six weeks of age. A second reason not to include hay in the diet of a young, pre-weaned calf is because it dilutes needed energy in the calf's total ration. After weaning or six weeks of age, the absorptive ability of the rumen has been developed and hay is then helpful in developing the musculature of the calf's stomach. The best choice is usually soft, palatable, grassy hay. Urea should not be fed to the young calf because the rumen is not fully functional and the urea will not be converted into microbial protein.
Relative sizes (% of whole) of the Stomach Compartments
(Adapted from Church, 1969, as adapted by Van Soest, 1982)
Clean, free-choice water should be available to calves at all times. Water is especially important for the development of the rumen microbes. Water promotes dry matter intake. The rumen bacteria need to live in a liquid environment. When the calf sucks milk, the esophageal groove is formed and milk bypasses the rumen and goes directly to the abomasum. Water goes into the rumen when the calf drinks it and the suckling response is not initiated. At 1-2 months of age, calves will drink 1.5-2.5 gallons (5.7-9.5 l) of water per day.
Effect of Free-Choice Water on Calf Performance to 28 Days of Age
|Daily Gain, Ibs
|Calf Starter Intake, Ibs
* Adapted from Kertz, A.F (JDS 67:2964)
Calves should be weaned if they are healthy, at least 28 days of age, and have consumed 2 pounds (0.91 kg) of calf starter for three consecutive days. Calves can be weaned by abruptly discontinuing milk feeding. However, stress on the calf may be reduced by gradually reducing the concentration of milk or milk replacer over a week's time. Keep the calf in the same pen until a week after weaning to reduce stress. Feed a mix of calf starter and heifer grain for 2-5 days before moving the calf to the heifer barn. This will reduce stress on the calf and help gradually adjust the calf to the new ration.
Scouring calves can develop severe diarrhea and become dehydrated, develop electrolyte imbalances and even die. Infectious causes of scours include: E. coli, clostridia, rotavirus, coronavirus, cryptosporidium, and coccidia. Non-infectious causes of scours include: poor nutrition of the dam, calving problems, poor intake of immunoglobulins from colostrum, overeating, and poor environmental conditions. Scours prevention programs should focus on its multiple causes and include: vaccination and good nutrition of the dam, colostrum management, calf nutrition, and cleanliness.
Most quality, commercial milk replacers include oxytetracycline (200 g/ton) and neomycin (400 g/ton). These antibiotics help in the prevention of scours especially in the first 2-3 weeks of life. Studies with medicated milk replacers have increased average daily gain in calves by over 50%.
Calves do not develop significant immunity to coccidia until after 100-120 days of age. They can potentially be infected up until two years of age. Calves that are stressed generally will show more signs of coccidiosis. Often, coccidiosis is seen just after weaning, especially if the calf is stressed by overcrowding and poor environmental conditions. A coccidiostat such as Deccox®, Bovatec®, or Monensin® should be included in the calf starter and in the heifer feed that the calf is being transitioned to.
Electrolyte solutions should be used to restore body fluids and minerals. These solutions should be fed in addition to the recommended daily amount of milk, not instead of it. It is best to feed the electrolyte solution halfway in between milk feedings. Commercial electrolyte solutions are available or they can be homemade.
Accelerated Growth Program
Cornell University researchers and Milk Specialties Company ( Dundee , IL ) have recently proposed to feed calves larger amounts of milk replacer with higher protein concentrations (30%) than the standard program described above. Milk replacer is mixed to contain 18% solids (rather than the traditional 12% solids). Calves are fed three times per day, 2-3 quarts (1.89-2.84 l)/feeding from Day 4 to Day 21 and 3-6 quarts (2.84-5.68 l)/feeding after Day 21. Milk replacer intake is reduced by 25% for the last 7-10 days prior to weaning. They recommend weaning at 28-35 days of age when the calf has consumed 2 pounds (0.91 kg)/day of calf starter for two consecutive days. They have observed growth rates 3-5 times greater than that of traditional programs.
More research is needed to clear up some questions on the accelerated growth program.
First, it is not clear if the long-term benefits of the accelerated growth program justify the extra cost. Second, the impact on health of calves fed according to the accelerated program is unknown. Third, the effect of large amounts of milk replacer consumption rather than grain consumption on rumen development is unknown. Part of the reason only one pound of milk replacer has been recommended in the past is to encourage early intake of grain. So far, on commercial dairy farms, some calf raisers have tried the accelerated growth program and really like it. Some have returned to a more traditional feeding program.
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Calf Starters and Rumen Development
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M. Jorgensen and P. Hoffman