A common pattern of raising calves is that the earlier the calves feed on the open feed, the better, the more the better, the calves feed on the open feed is closely related to the development of the rumen. And contrary to this view, there are indications that,Milk does not fully meet the energy and protein needs of young calves and needs to be compensated by other sources of nutrients.

The rumen of calves is not fully developed, so they cannot effectively use the nutrients in the starter. The energy, protein, or milk substitute produced from dairy products can be more utilized and digested by calves. Therefore, it is not recommended to feed milk substituents containing soy protein to calves less than 3-4 weeks of age.

A steady level of milk (20% of birth weight) must be continuously supplied before the calves can digest enough starter and start weaning. Unfortunately, crude protein levels in regular commercial calf feedstocks are typically only 17-18%.

On a dry matter basis, the protein level of Holstein cow's whole milk is about 27%, which means that the protein level will be significantly reduced when transitioning from full milk to regular calf feed, which also means that calves must eat enough feed before weaning to meet their nutritional needs after weaning.

In addition, it is also important to consider that the rumen fermentation efficiency of young cows is not as efficient as that of adult cows, so their utilization of nutrients in the open food is very limited.

In general, if calves are fed an 18% protein starter, the calves must consume 4 pounds of starter per day for 3 consecutive days before weaning. However, if a high-quality starter (24-25% protein) is fed, the calf can consume 2 pounds of starter per day for 2 consecutive days before weaning begins.

There is also a general concern that if a large amount of milk is fed to the calves, the desire to eat the open feed will be significantly delayed. Again, the problem I would like to point out is that prematurely eating open foods can cause nutritional disorders.

In the beginning, calves will certainly not eat too much open food. However, dry matter intake is based on body weight, and calves fed with a large amount of milk may gain more than 2 pounds per day, while under traditional milk feeding schemes may gain only 0.5-0.75 pounds per day. Because well-fed calves take in more nutrients every day, and as they gain weight, the desire to eat dry matter will become stronger. At the age of 4-6 weeks of calves, their feed intake to the starting feed will increase significantly, and calves are likely to be able to feed enough nutrients until weaning at 7-10 weeks of age.

This process, known as the "transition period", from a whole milk diet (or milk plus some dry feed) to a 100 per cent dry feed diet, is more complicated than expected. In designing a successful transitional nutrition management programme for calves, two important factors must be taken into account, one being the ability of calves to consume sufficient quantities of good quality starter to meet their pre-weaning nutritional needs, and the other being the adequacy of rumen development. Both of these factors are easily overlooked so that calves are only weaned on a day/week age basis.

What criteria can we use to determine whether a calf starter is of high quality?

Protein content: firstProteinThe content is at least 22%, preferably 24-25%.Secondly, itsProtein source is best soybean meal,BecauseSoybean MealIt has a good amino acid balance and is easily digested and degraded in the rumen.

 

rumen-protected soybean meal

rumen bypass protein: The open food should also contain some rumen bypass protein. The ability of the developing rumen to utilize proteins is limited, so proteins that are not digested becomerumen bypass protein, transferred to the small intestine for further digestion and absorption.

Starch: In addition, the calf starter must also contain readily available starch. Whole grain corn is commonly used in production, but its starch is not quickly digested and may hinder rumen development. The quality of calf starter must be stable, especially the moisture content. Calves are very habit-dependent and do not like to change feed composition, which can lead to lower dry matter intake.

calvesIts rumen is much smaller than its abomasum at birth. The rumen muscle tissue is not fully developed and lacks rumen papillae. When a calf is born, its rumen is sterile, so the first bacteria that enter the rumen are ingested from the environment. The vast majority of these bacteria are "aerobic," requiring oxygen to grow. The rumen environment of adult cows is anaerobic, and accordingly, bacteria need an anaerobic environment to grow. During the development of the rumen, aerobic bacteria are transformed into anaerobic bacteria.

Bacteria need a liquid environment to grow. Unfortunately, there are still cattle farms that do not provide drinking water to calves who feed on milk, or only provide limited drinking water. This inhibits the growth of rumen bacteria, which retards rumen development. It can often be observed that calves with restricted drinking water have a very difficult post-weaning growth and a higher probability of respiratory diseases.

Many people have the misconception that 90% of milk is water, so it can meet the drinking needs of calves. However, no matter whether calves drink milk from a bottle or a milk bucket, their esophageal ditch is closed, and milk will pass through the rumen and directly enter the abomasum. In this case, the demand for water from rumen bacteria cannot be met.

If the calf drinks directly from the milk bucket, the water will flow directly into the rumen. A significant proportion of calves also consume clean drinking water after taking milk. Many studies have shown that if calves have free access to drinking water, their open feed intake will be significantly increased, and rumen development can be accelerated and calf growth rate can be increased.

Calf starter must contain readily available starch. When starch is fermented in the rumen, a large amount of butyric acid is produced. Studies have shown that butyric acid has a greater effect on rumen volume and rumen papilla development than other substances in the rumen.

Volatile fatty acids (VFAs) are produced when feed is fermented in the rumen, and the rumen nipple is essential for the absorption of volatile fatty acids. VFAs are an important energy source, but the dysplasia of the rumen can not effectively absorb VFAs, resulting in the continuous accumulation of VFAs in the rumen, which may eventually lead to serious problems such as ruminal acidosis.

Corn is a common source of starch in calves, and its utilization forms are various. Steam flaked corn has the highest starch utilization rate, but there is a problem that steam flaked corn is very thin and fragile, which may produce a large amount of powder.

The processing temperature for roll flake corn is lower, so the flake thickness is slightly larger, and the amount of powder is lower than that of steam flake corn, but still higher than expected.

Impact-type flaking corn is also rolled, but to a much lesser extent, and the thickness of impact-type flaking corn will be significantly higher than that of regular-to-roll flaking corn, and its starch utilization rate is comparable to that of roll-to-roll flaking corn due to its ease of chewing by calves. Some open foods contain whole grains of corn, which are very palatable, but starch is not easily digested and utilized by rumen bacteria.

A number of studies have shown that the rumen development of calves fed with whole corn is slower than that fed with other forms of corn. Therefore, the use of whole grain corn in the calf starter should be avoided as much as possible. Some starches also contain a small amount of flaked barley, which serves as a source of rapidly digestible starch and can quickly provide starch to rumen bacteria before corn starch is digested.

There are three available forms of calf starter: organized starter, granular starter and powdered starter. recommend the use of a textured form of open foodThere are several reasons: first of all, good palatability, dry matter intake is higher than other forms of open food; in addition, this form of open food can be very good to promote the development of rumen wall muscle.

If the calves in lactation can not feed to the roughage, then the muscle layer of the rumen wall can not develop normally. However, studies have shown that if the use of organized open feed, then even if the calves are not provided with roughage, the rumen muscle layer can be fully developed. The size of the tablet has an important influence on the process, whether it is organized to open the food or granules. Unfortunately, however, many of the ingredients are tableted with small pellets (8mm in diameter), which are not as effective in the development of the rumen papilla. I personally recommend larger diameter 12 mm tablets.

If parallel tests are carried out for comparison, the feed intake of the organized open feed is 15% higher than that of the granular feed on average. Some cattle farms produce their own calf starter, but they usually do not have the ability to produce tablets on the pasture, so the starter they produce is a mixture of various ground feeds and flour. In general, calves do not like this form of feed, and their dry matter intake will be much lower than that of the pellet or texturized form of the starter feed.

In order for calves to have a good transition period, the weaning process must be synchronized with rumen development. Many pictures of well-developed rumen at 4 weeks of age can be found on the web. But these calves fail to consume the equivalent of 20 percent of their body weight in milk every day, essentially causing them to look elsewhere for the nutrients they need to survive. Again, if prematurely ingestion of large amounts of starter is observed in calves, this is an indication that the calves are not getting enough nutrients in the milk to meet their growth and maintenance needs.

Because the rumen of calves is not perfect when they start to eat the open feed, only a small part of the rumen is really involved in the digestion and utilization of nutrients. As a result, calves cannot get enough nutrients from limited milk and starters to allow them to achieve their genetic growth potential. Sometimes even though the rumen is well developed (calves are 4 weeks old), calves still don't grow well and their immune systems don't function properly because they don't get enough nutrients.

If calves can consume milk equivalent to 20% of their birth weight every day from the second week of birth, the feed intake of the starter will gradually increase as they grow. Once they reach the weight that requires more nutrients, the feed intake of the starter will increase accordingly. At the age of 7-10 weeks, the intake of low-quality raw materials (protein content 18%) can reach approximately 4 pounds, or the intake of high-quality raw materials (protein content 24%-25%) can reach 2 pounds. This part of the time is sufficient for the rumen of the calves to be fully developed to digest and ferment the feed they eat.

It is best to feed only the calves with open feed (no roughage) within 7-14 days after weaning, so as to further promote rumen development and facilitate starch fermentation and butyric acid production in the later stage. Calves should stay in calf barns or separate cowsheds during this time to observe their daily feed intake on the open feed.

Traditional weaning protocols for calves believe that they should be weaned at a certain age. If this approach is taken, the milk supply will be reduced at a certain age, forcing the calves to eat more starter. Usually calves have only one week to reduce their milk intake before weaning.

The main problem with this scheme is that the calves do not have enough time to fully develop the rumen before weaning. They are forced to consume more starter food in an attempt to satisfy their appetite and nutritional needs, but their rumen is not sufficiently developed to ferment these feeds effectively. These calves often suffer from rumen acidosis, also in the rumen papilla surface formation "straw mat".

In recent years, farmers have gradually improved their awareness and began to increase the amount of milk fed to calves. This also results in an increase in the number of automatic feeders used. The feeding program of many pastures is very flexible, and any feeding program can be performed. However, there are also many pastures with complex programming of the feeding program, which can adjust the amount of milk fed up and down as the age of the cows changes.

The common method is to gradually increase the amount of milk fed every day until it reaches a certain level, and then, in turn, rapidly reduce the milk supply and stimulate the intake of the calves to the open feed. Most procedures can achieve weaning before 8 weeks of age. Again, this method will force calves to eat more open feed, but their rumen may not be fully developed and may not be able to effectively digest or ferment dry feed.

The main problem with this computer-controlled feeder is that when the calves are raised in a herd, the feed intake of each individual cannot be observed. Although this scheme can reduce milk intake, some calves still cannot get enough starter food before weaning to meet the nutritional requirements after weaning. This is why we often see calves gain weight slowly, grow hard, and have an increased incidence of respiratory diseases after weaning.

In many cases, ventilation is not considered when computerized feeders are fitted into existing buildings. Therefore, after the transfer of calves to poorly ventilated barns, many farmers have experienced severe respiratory diseases and increased mortality in calves.

Some dairy farms in low temperature areas have developed schemes for feeding fermented milk. In these cases, the calves were free to take milk at any time. The low pH of fermented milk limits the amount of milk that calves can consume per day, but they can still consume 12 pints or more of milk per day.

These calves gain weight very quickly, but the same problem occurs when they are weaned. They are usually raised in groups and must be fed less before weaning, and some calves may not be able to consume sufficient milk at weaning because individual milk intake cannot be monitored. In this system, an increase in respiratory disease is also observed in poorly ventilated cowsheds.Rocky Lick Brick

A successful calf transition feeding management program must allow the rumen to fully develop, can effectively ferment dry feed. It must also be able to provide the necessary nutrients to allow the calves to gain weight and grow in line with their genetic potential.

The traditional calf feeding scheme only provides calves with 10% of their birth weight of milk every day. In fact, calves are not full. When the temperature is too low or heat stress, it often causes weight loss and morbidity increase. A very simple and easy-to-achieve goal is to make calves reach twice their weaning weight at 8 weeks of age.

When designing the calf transition feeding plan, the above-mentioned problems should be considered more, which can greatly improve the weight gain and will not cause excessive fat deposition. Calves will be healthier and have lower morbidity and mortality. Reserve cows are more likely to reach suitable body condition for mating. The first calving time of cows is shortened, and milk production will also be improved.