Feeding Management of High-producing Dairy Cows and Application of Growth Hormone
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(I) Feeding and management of high-yielding dairy cows I. INTRODUCTION Due to the different geographical environment, all regions of the world have their own dairy farming systems. However, regardless of the type of system adopted, economic efficiency is the purpose. For example, in areas with mild climate, a large number of excellent pastures can be produced. The feeding system in these areas is grassland grazing, and the cost is relatively low. However, in countries and regions where non-grass reared, large amounts of concentrate have to be used to supplement the lack of nutrition. In fact, even if the number of breeding heads is reduced in order to increase the unit yield of dairy cows in areas where grassland is raised, fine material is often indispensable. In fact, no matter what kind of environmental conditions, it is impossible to rely on forage to supply the nutrition of high-yielding dairy cows. It has been found in the experiment (Hutton, 1995) that no matter how good the grass is, it can't meet the output above 4,000 kg. The nutritional needs of dairy cows. The so-called high-producing dairy cows are not a new term, and there were records of milk production of 10,000 kilograms more than 100 years ago (Boutflour, 1967). With the continuous improvement of modern breeding techniques, the world can now find many cattle with an average milk production of 10,000 kg or more. In recent years, Taiwan has introduced many excellent breeds of cows from the United States, Canada and other countries, which has a high potential for production. However, under the current feeding system in Taiwan, especially affected by climate and other factors, dairy cows can hardly reach their due potential. We have made a rough estimate that 1,000 to 1,500 kilograms of milk production was lost due to poor environment, 1,000 to 1,500 kilograms of milk production was lost due to not reaching the ideal milk production peak, and there were 1,000 kilograms. The amount of milk produced was lost due to improper feeding and management. In other words, at present, milk production in Taiwan is at least 4,000 to 5,000 kilograms away from its expected milk production. Therefore, with proper feeding and management, finding half of them should be no problem. Second, the growth stage of cattle feeding and management In the feeding and management process, dairy farmers often pay attention to the lactation stage of the cattle, but often neglected the growing stage of feeding and management. Actually, the growth stage of dairy cows, especially 12-24 months of age, is of great significance to their final milk production (Waldo & Capuco, 1992). Comprehensive research data prove that it is most suitable for cows to weigh between 550 and 600 kg before the first delivery at 24 months of age. At the same time, before sexual maturity (puberty), animals grow too fast and can seriously affect the development of the breast and later the potential for milk production. It is generally believed that between 3 and 9 months of age, animals should be prevented from ingesting excessively high energy. Take Dutch large cattle as an example. The growth rate at this stage should not exceed 600 g/day. After 9 months of age, especially after mating, it is extremely important to maintain the normal development and growth of the mother and fetus so that the mother can achieve an ideal weight before delivery. During the growth process, like the lactation period, the quality of the nutrients actually eaten depends on the formula of the feed and the feed intake itself, and it is also influenced by other factors. In fact, under the condition of a certain feed formulation, the nutrients it actually eats are not a fixed value. A recent study using TMR on growing cows aged 12-24 weeks (Morrice, 1995) found that animals should be fed in stages to achieve and maintain a desired body weight during the growing period. For example, it is advisable to use TMB coarse concentrate ratio 50:50 from 12 - 18 weeks old. Feed intake of 4 kg of dry matter at this stage; 18-24 weeks of age should be changed according to the previous stage feed formulation and energy concentration, so that the animal feed intake is maintained at 5.5-6 kg. The experiment also found that if conditions allow, 12-24 weeks of age should be divided into three stages of feeding: 12-16 weeks, 16-20 weeks, 20-24 weeks, corresponding to the proportion of coarse concentrate is divided into 30-35:70 - 65, 50:50, 70:30 is appropriate. Feed intake is 3.5 - 4 kg, 4.5 - 5.5 kg, 5.5 - 6 kg respectively. In short, it is necessary to maintain an ideal weight change throughout the breeding process: 100 kg for 12 weeks, 175 kg for 24 weeks, 350 - 400 kg for 12 months, and about 600 kg for 24 months. The body condition of the dairy cow is also very important during delivery and throughout the lactation process. Maintaining proper body conditions can maintain a high level of milk production while preventing metabolic and reproductive diseases. The scoring method is usually used to measure the body condition of an animal. This is based on the body condition, body condition, and obesity of the cow. The animal is divided into several grades artificially and expressed by numbers. In many regions, it is set to 1 - 5 points, while in Australia and New Zealand it is set to 1 - 8 points. A lower score means that the animal's condition is getting worse and thinner. When the animal reaches the highest score, it means the animal's body. Very fat, energy reserves have reached a very high level. According to Australia's grading standards, it is most appropriate for animals to maintain 5-6 points during childbirth and lactation. Third, the lactation cycle in different stages of the entire lactation process, dairy cows on the demand for nutrients there is a big difference, especially the high-yield dairy cow is more obvious, this is due to milk lactation has a clear change in the law, and The corresponding feed intake does not occur simultaneously and it is extremely important to understand this in production. From the time of delivery to the peak of lactation (usually 6 - 8 weeks) is the first stage. At this stage, the animal itself has low feed intake, gradually increases the amount of lactation, gradually reduces body weight, and the body condition deteriorates. Animal feed intake at this stage Not enough to meet the demand for milk production, in a nutritionally negative balance. Animals have to use their internal reserves of energy and nutrients to maintain high milk production. Therefore, the animal's body condition at this stage will become worse and worse. This is a crucial stage in production. On the one hand, it is necessary to avoid as much as possible the deterioration of the animal's body condition. On the other hand, the animal should try its best to exert the potential of lactation peak. . Lactation peaks are one of the most critical factors in determining milk production throughout the lactation period. The results of the study (Broster and Thomas, 1981) show that there is a high correlation between milk production at the peak of lactation and milk production throughout the lactation period. If we can think of ways to produce more than 1 kilogram of animals during the peak period, animals can get 150 to 200 kilograms more during the entire lactation period (McDowell, 1995). The second stage is from the peak of lactation to the peak of feed intake. The peak of feed intake is usually about one month later than the peak of milk production. The biggest feature of this stage is that the milk production and feed intake are so high that the animals are in nutrition. Balanced state. Cows during this period are extremely sensitive to the feed and the surrounding environment, and any "stress" factors can cause serious damage to milk production. For example, in Taiwan, if high temperatures and heat are encountered at this stage, milk production will rapidly decline. During the peak period of lactation, it is almost impossible to recover the decline in milk production for any reason, which is a frequent problem in Taiwan. The third stage is the post-lactation period, in which feeding and management are relatively easy. During this period, the intake of dairy cows is high, and the milk production is gradually reduced. The nutrition is in a positive balance and the weight will gradually increase. At this time, most of the dairy cows may be pregnant and they should be considered as the next one for raising. Prepare for the milk period. Under normal circumstances, the situation of dairy cows will gradually become better during this period. The fourth stage, the so-called dry period, usually maintains a good body condition or a slight increase. IV. Feeding management of high-yielding dairy cows: From the above analysis, it can be clearly seen that the feeding of the first lactation stage is the most challenging, which is particularly important for high-producing animals. Therefore, it is necessary to feed animals with high nutrient-concentration feeds at this stage, while also considering feed palatability and digestibility. In the long-term breeding process, high-producing animals have acquired many congenital traits, including good appetite, high feed intake, and high feed efficiency. Many factors can affect the feed intake of dairy cows. The industry needs to understand many physiological changes in the animals themselves in order to truly cater to their needs. In the energy consumed by non-ruminant animals, the growth rate and production level of protein (amino acid) and its proportion of animals have a significant impact (Henry and Seve, 1993). Although ruminants have obvious characteristics of ruminal nutrition, the degree of energy in feed intake and the degree of protein over rumen make nutrition problems extremely complicated. For high-producing animals, the nutrient advantages of rumen microbes must be fully utilized. To add a sufficient amount of rumen nutrition. Supplemental fat (or rumen-protected fat) is currently an effective way to address energy deficits. Adding the right amount of fat to the diet can increase the energy concentration on the one hand, allowing the animal to obtain more energy at a certain feed intake, and on the other hand, it can improve Fatty rate. The addition of ruminal proteins to feed is also important for high-producing animals. It is generally believed that 60% of the protein requirement of a high-yielding dairy cow is provided by rumen bacteria protein and 40% by rumen protein (UIP). For example, a dairy cow with a daily output of 35 kilograms needs about 4 kilograms of protein per day, of which 1.6 kilograms need to be provided by UIP. The UIP content of traditionally used cattle feed, soy flour, corn and forage grass is not high, and many animal feeds such as fish meal, bone meal and blood meal have high UIP content, and animal protein feeds are used. It will help provide reasonable protein for high-producing animals. At present, under the feeding system in Taiwan, animals often lack energy rather than protein, and protein feed costs are relatively high. Under such conditions, the use of low-protein and high-energy diets in conjunction with diets is reasonable, and the availability of amino acids, such as methionine and lysine, which are easily lacking in rumen protection in animals, will be economical and effective in production. The concentration of starch and non-starch carbohydrates in the concentrate, and the ratio of the fines in the diet (TMR), are also the main factors affecting dairy production and health. Concentrates are too harmful and unhelpful. Under normal conditions, the rumen is basically acidic and neutral. Most of the metabolites in the rumen are acidic. The acidic rumen environment is neutralized by a large amount of hemiparatic saliva, so that the rumen environment is relatively balanced. The rumen microorganisms can be divided into different breeds and flora, acting on different components of the feed, as well as different metabolites. These rumen microorganisms of different breeds and flora, the crude cellulose and non-fibrous carbon in the feed The proportion of compounds is extremely sensitive. For example, if the proportion of concentrate in the diet increases, especially when cereal concentrates increase, it can cause a rapid increase in the production of lactic acid in the rumen. At the same time, diets that are low in fiber can also reduce the secretion of saliva. This results in a decrease in the pH of the rumen. The experiment found that if the pH value in the rumen decreased from 6.75 to 4.75, it would seriously affect the reproduction of microorganisms in the rumen, and some microorganisms would even disappear, resulting in impaired rumen normal function, which is acidosis. In the intensive production system, ruminal acidosis is the main cause of some diseases and affect productivity, including reduced milk production, reduced milk fat percentage, laminitis, and ketosis. In order to prevent ruminal acidosis, the use of TMB mixed feed is a powerful measure, so that the rough material can be fed at the same time, there is no time for concentrate alone, if the concentrate must be fed alone, it should also be small meals, Reduce the amount of time that concentrates can be used alone. Application of high-quality forage can reduce concentrate consumption. Adding the right amount of fat as a source of energy in the diet can also reduce the amount of concentrate. Feeding a pH buffer or feeding a microbial fermentation product helps to maintain the balance of acid and rubidium in the rumen. Under the current feed conditions in Taiwan, there is a general lack of trace components such as beta-carotene, which has a direct or indirect relationship with the breeding problems that often occur on the site. Adding an appropriate amount of Beta- to the feed for dairy cows - Carotene is the main measure to increase milk production and prolong production life. V. CONCLUSIONS As mentioned above, the feeding and management of dairy cows with a milk yield of 10,000 kg or more is not a mystery process. Of course, there are no absolute rules. The industry should fully understand the physiological characteristics and habits of dairy cows, and combine the specific conditions of their own farms to take reasonable measures to give full play to the potential of dairy cows. (B) the application of growth hormone in the production of dairy animals I. Introduction Growth hormone (GH) is one of the major protein hormones in animal metabolism regulation. This hormone, secreted by the pituitary gland, is secreted by the thalamic secreted GH-releasing factor (GRF) and GH-releasing inhibitor (SRIF). Studies have shown that the injection of GH to dairy animals can significantly increase milk production and improve feed utilization efficiency. At present, GH can be mass produced by synthetic DNA technology. The application of exogenous GH in the production of dairy animals has a bright future. The experimental results also show that: immune SRIF can improve the digestibility of dry matter in animals, increase milk production and feed utilization efficiency. Recent studies have found that antibodies produced by multiple chains in the GH molecule bind to GH in vivo to enhance the physiological function of GH. These multi-strand direct injections of antibodies produced in vivo also have similar effects. If these multi-chains can be produced in the form of vaccines for dairy animal production, they will bring great benefits to the industry. To date, the increase in the level of production of dairy animals has mostly been through improved nutrition, feed management and breeding techniques. With the continuous improvement of modern biological products technology, controlling the animal's own endocrine system or applying the corresponding exogenous hormones has become a new measure to further increase animal production capacity. Growth hormone (GH) is one of the most important hormones in the body to regulate the production of metabolic effects. The physiological function of GH has been fully studied and confirmed. It can stimulate cell division and promote bone growth and protein synthesis. This hormone is secreted by the pituitary and secreted by the liver IGF-I directly or indirectly acts on different body tissues, in lactating animals can significantly increase milk production. The secretion of this hormone is controlled by the neuroendocrine system, including the promotion of GRF and the inhibitory effect of SRIF, and the balance between them maintains the physiological level and effect of GH in vivo. In recent years, the application of exogenous GH and the control of GH secretion and function in the production of dairy animals have attracted the attention of the academic community and the industry. For example, the United States Food and Drug Administration (FDA) after many years of careful analysis and research confirmed that the injection of GH can increase milk production and have no adverse effects on humans and animals themselves, and finally agreed that GH can be used for dairy cows to increase production capacity. However, many countries and regions still prohibit the use of this hormone. Second, the impact of GH injection on milk production: In recent years, a large number of studies around the world have demonstrated that the injection of exogenous GH (either daily injection or injection of slow-release products every 14 or 28 days) The milk-producing properties affecting dairy animals (Table 1). Significant increase in apparent increase From Table 1, it can be seen that whether the short-term or long-term injection of GH can significantly increase milk production in dairy animals, and long-term application has no effect on milk composition. In one of our studies, it was found that the injection of exogenous GH in the first few days mainly affected the redistribution of nutrients in dairy animals. That is, the use of nutrients stored in the body is distributed to the breast tissue to support high-yield nutritional needs. Therefore, animals lost weight in the first few days of GH application. With the extension of the application time, about one week later, the animal will increase its intake, in order to maintain a higher level of lactation while restoring weight. In the study, it was also found that the effect of GH application in the early stage of lactation was not significant, but it was significant in the late stage of lactation. This may be due to the fact that the initial animal can secrete a sufficient amount of endogenous GH, and the initial animal has been in a serious negative nutritional balance. Third, the impact of immune SRIF on milk animals Growth hormone release inhibitor (SRIF) has been confirmed to control the secretion of GH, while it can affect the gastrointestinal motility and feed through the speed of the digestive tract. Therefore, the immunization of SRIF can provide a new way for the industry to improve the animal's productivity. We conducted a study on lactating sheep as a test animal. We injected SRIF antibody preparations before delivery and two weeks after childbirth, and measured the milk production and dry matter digestibility of the animals after delivery. The results showed that immune SRIF can significantly improve the animal's milk production and feed efficiency. The experimental results also show that this treatment has no effect on the milk composition. Physiological determination results show that this treatment can improve the animal's digestibility of dry matter, but it does not increase the blood GH concentration, but increases the concentration of blood glucose in the blood. This shows that immunization SRIF increases milk production due to improvement. Gastrointestinal function is not due to direct increase in GH secretion. Fourth, the role of growth hormone vaccine Natural physiological state of GH is a protein hormone with a distinct three-dimensional structure. However, different parts of the structure have different roles and functions. In the experiment, it was found that the antibody produced by amino acid sequences 35 - 53 and 134 - 154 in the GH molecule structure can enhance the function of GH, thereby increasing the productivity of animals. This may be due to the function of these antibodies in the body and GH in the blood, thereby increasing the animal's productivity. This may be due to the fact that these antibodies bind to GH in the bloodstream in vivo, which can prolong the physiological half-life of GH and increase the binding of GH to the receptor. Most of the antibodies used in the experiments were produced by experimental animals such as rabbits. Subsequent studies have also found that if these multiple chains are directly injected into animals as vaccine formulations, antibodies produced in animals have the same effect. The experimental results using this vaccine for dairy animals have demonstrated that animals can increase milk production. If used together with GH is more obvious, the current application of this vaccine is still in the research stage, once successful may bring a revolutionary impact on the industry. V. Conclusion The application of exogenous GH or physiological regulation and control of endogenous GH is a potential new biological technology. The application in dairy animal production has brilliant prospects, especially in intensive production conditions. Next, it is extremely important to increase individual milk production and reduce the number of heads. However, the industry should apply under the guidance of the government and related personnel.