Key Technical Points for the Feeding and Management of Dairy Calves
I. Feeding Preparation for Newborn Calves
1. Care of Newborn Calves
Immediately after the calf is born, wipe away the mucus from the mouth, nose and ears with a clean towel, and dry the body. When the weather is cold and the temperature is low, the body should be dried with heat; to speed up blood circulation, wipe the body with a dry cloth. When the calf's breathing is weak, artificial respiration should be performed; squeeze out the retained blood in the umbilical cord, cut the umbilical cord about 5 mm from the base of the abdominal wall, and soak the cut end in 7%-10% iodine tincture for 1 minute; feed the first colostrum 30-50 minutes after birth, with a feeding amount of about 2 kg, and feed for 5-7 days; weigh the calf, fill in the birth record, and establish a file for the newborn calf.
2. Properly Apply Markings Such as Ear Tags and Ear Numbers
Accurately marking cows is the basis for breeding, milk production records and immunization. Markings are divided into permanent and non-permanent types. Permanent ones include branding (acid branding, alkali branding, fire branding and liquid nitrogen freeze branding), pattern diagrams and ear prints; non-permanent methods include neck collars and marking paint numbers.
3. Dehorning
The purpose is to prevent cattle from injuring people or harming other cattle. Dehorn at 7-30 days, using a branding iron or 20% caustic soda to destroy the horn base cells. Dehorning methods include: the electric cauterization method, using electric cauterization to dehorn calves before 30 days of age; the sodium (potassium) hydroxide cauterization method, used for calves 1-3 weeks old; for larger calves and adult cattle, a chisel or saw can be used to remove the horns.
4. Individual Pen Rearing Method
Raising newborn calves in separate calf rearing pens is a form of individual rearing. A calf is kept in one pen from birth until weaning. Its advantages are: the pen is ventilated, the air is fresh, the light is sufficient, and movement is free, which can strengthen the calf's physique and improve disease resistance. The calf is always raised alone in one pen, avoiding the opportunity to suckle each other or come into contact with other cattle, reducing the spread of pathogenic microorganisms, and lowering the incidence of disease in calves. It ensures the calf's feed intake and avoids the phenomenon of competing for food. It makes it easy to find sick calves, facilitates treatment and observation, and can play a role in isolating sick calves. The pen is relatively small, making it easy to clean and disinfect, which is conducive to disease control. The pen structure is simple, and the construction cost is relatively low. Once a disease breaks out and the pen is contaminated by pathogenic microorganisms, the calf pen can be disinfected and moved to a new site, making it convenient to renew the calf rearing site. Practice has proved that the individual pen rearing method for calves plays an important role in controlling the occurrence of calf colibacillosis and reducing calf navel inflammation, etc.
II. Key Management Points for Calves
Ensure that the calf receives 2-3.8 liters of colostrum within 1 hour of birth; if necessary, use an esophageal feeder or bottle to feed milk, and ensure the quality of the colostrum. Within 12-24 hours after birth, the calf should be fed colostrum 3-4 times, about 2 liters each time. The survival rate of 2-day-old calves should reach 95% (there is no correlation between calf birth weight and its later production). Feeding colostrum should be done at fixed times, in fixed amounts, by a fixed person, and at a fixed temperature (the average colostrum temperature is 38°C). Practice has proved that the amount and quality fed, the time of the first feeding and the duration of colostrum feeding are all quite important.
III. Management Methods from Birth to Weaning Stage
1. Management Objectives
The mortality rate from birth to weaning should be less than 2%; before weaning, the calf's concentrate intake should reach at least 1 kg/day; rumen function gradually improves; the average daily gain should reach more than 700 g, and daily gain is positively correlated with first-lactation milk yield.
2. Characteristics of Changes in This Stage
It is highly prone to some disease infections, such as pneumonia, diarrhea, limb paralysis, and septicemia, etc.; it has poor adaptability to unfavorable environments, little body fat deposition, and a relatively high mortality rate; newborn calves basically do not digest protein, fat and carbohydrates before the rumen is fully developed; calf growth mainly occurs after rumen function is fully developed and with the intake of dry forage and starter feed.
3. Feeding Methods
Feeding starter feed and high-quality forage should begin after 5-7 days of birth, because the intake of starter feed is the key to functional rumen development; calves should obtain an appropriate amount of nutrients from starter feed in the second week. In order to encourage calves to eat starter feed, from the first week calves should have free access to water and nutritious, highly palatable starter feed until weaning. Ensure the quality of fresh milk (eliminate alcohol-positive milk, antibiotic milk, low-fat or low-protein milk). However, feeding too much milk will delay the development of starter feed intake and the age at weaning. Under hot (cold) climate conditions, supplying cool water (warm water) 2-3 times a day helps resist heat (cold) stress and promotes increased feed intake in starter-fed calves; if water is available freely, calves can drink 4.9-7.6 liters/day in the first month after birth, so a large amount of clean and hygienic drinking water must be provided; fresh water is necessary for calf growth and dry feed intake (as a solvent for nutrients, a temperature regulator and an osmotic pressure regulator), and the water trough should be easily accessible to calves, no higher than 71 cm from the ground. A one-week interval should be allowed between weaning and group transfer; group transfer should be carried out 1-2 weeks after weaning, after the calf has adapted to the stress response of weaning. Delayed weaning is often caused by improper rumen fermentation due to poor development of the rumen and reticulum. If the calf starter feed is ground too finely, it is not conducive to the development of rumen papillae or the reticulum. Generally, hay should be cut to 2.5 cm long and mixed with calf starter feed at 1:10. A hay proportion exceeding 10% will affect starter feed intake.