Application of fatty acid calcium in ruminant feed

Adding fat to the diet of ruminants, especially lactating dairy cows, can solve the problem of negative energy balance. However, adding fat directly will bring some negative effects, such as affecting rumen fermentation, reducing milk fat rate and dry matter intake, etc., so its addition level is limited. In this case, protective fat comes into being. The earliest protective oil was made by Scott in 1970 by coating oil with casein and then treating it with formaldehyde, but it was difficult to promote in production because of its high cost. Later, based on this principle, people developed a calcium soap-type protective oil, namely calcium fatty acid. At present, fatty acid calcium is widely used in more than 40 countries such as Europe, America and Japan, while the application research of fatty acid calcium in my country is still in its infancy. This article only provides an overview of the application and research progress of fatty acid calcium in ruminants, especially dairy cattle feed, for reference.
The role of fatty acid calcium 

When people solve the problem of negative energy balance in high-yielding dairy cows, the first thing to do is to increase the energy concentration by adjusting the ratio of refined and coarse feeds. However, this practice leads to a change in the type of rumen fermentation, which reduces the milk fat rate, and is prone to cause acidosis and other metabolic disorders in dairy cows. Later, people proposed the method of adding oil to the diet, which can not only increase the energy concentration of the diet, but also not cause acidosis in dairy cows. However, the addition of unprotected oil has a strong inhibitory effect on rumen fermentation, and the oil wraps around the fiber, preventing the contact of microorganisms with the fiber, and significantly reducing the digestibility of cellulose. In addition, long-chain fatty acids combine with cations in the rumen to form insoluble complexes, which affect the concentration of cations required for microbial activity, thereby affecting the pH of the rumen environment and reducing the milk fat rate. These disadvantages limit the application of greases. A large number of experimental studies have shown that the addition of fatty acid calcium can overcome the above drawbacks. The ionization constant of fatty acid calcium is between 4 and 5. When the pH is less than 6, it can promote its ionization. It is insoluble in the neutral environment of the rumen. When it reaches the true stomach and small intestine, it dissolves and decomposes in an acidic environment. Fatty acids and Ca2+ are converted into fatty acids and Ca2+, so that fatty acids avoid interaction with rumen microorganisms, and are fully utilized as energy after reaching the true stomach and small intestine, and Ca2+ is also supplemented.
Types of fatty acid calcium
According to the length of its saponified fatty acid chain, fatty acid calcium can be divided into long-chain fatty acid calcium, medium-chain fatty acid calcium and short-chain fatty acid calcium. The long-chain fatty acid calcium is widely used in the dairy industry, and calcium palmitate is the most widely used in foreign countries.
Application effect of fatty acid calcium
Improve milk production of dairy cows Many studies have shown that adding fatty acid calcium to dairy cow diets can significantly improve milk production. Schneider et al. (1998) data show that adding 4% calcium fatty acid to the dairy cow's diet increases milk production by 4%.
Increase milk fat rate and improve milk quality Schauff et al. (1992) added 3%, 6%, and 9% of fatty acid calcium to dairy cow diets, and the results increased milk fat rate by 4.23%, 15.71% and 17.22%, respectively. . Experiments show that the addition of fatty acid calcium, although the milk fat rate has increased, but the milk protein content has a downward trend, but due to the increase in the total milk production, the total milk protein has not decreased.
Improve the reproductive performance of dairy cows Sklan et al. (1991) test results show that adding 2.6% fatty acid calcium to dairy cows diet, the degree of postpartum weight loss of dairy cows is significantly lower than that of the control group, and in the 2nd to 4th estrus, conception The rate was significantly higher than that of the control group (42.6%: 25.0%), and the cows that were pregnant 150 days after giving birth were also significantly higher than the control group. (82.4%: 62.5%).

Effects on other ruminants Calcium fatty acid not only improves the production performance of dairy cattle, but also improves the meat production performance of beef cattle and mutton sheep. Japanese studies have shown that adding fatty acid calcium 200g/d·head to beef cattle's diet can increase the daily weight gain of beef cattle by 0.05kg/d·head, the feed remuneration is also improved, and the content of unsaturated fatty acids in muscles is significantly increased. The author's test results show that adding fatty acid calcium 10, 20, and 30 g/d·head to the diet of house-fed finishing lambs can increase the daily feed intake of lambs by 0.11, 0.19, and 0.09 kg, respectively, compared with the control group. /d·head, the daily weight gain increased by 0.038, 0.034, 0.016 kg/d·head respectively compared with the control group. At the same time, the contents of protein, fat, cholesterol and other nutrients in mutton were increased accordingly.
Factors affecting the action of fatty acid calcium and precautions for use: The type of fatty acid saponified
with calcium affects the effect of fatty acid calcium. The purpose of adding fatty acid calcium is to protect the fatty acid so that it can pass through the rumen and reach the true stomach and small intestine to be fully utilized. But different fatty acids have different utilization efficiencies, and there are many factors that affect the absorption of fatty acids.
    For example, the polarity and emulsification of fatty acids, which are determined by carbon chain length and saturation, are related to the absorption and utilization of fatty acids. Experiments show that the effect of long-chain fatty acid calcium is better than that of short-chain fatty acid calcium.
Feed factors The crude fiber, crude protein and energy levels in the feed affect the effect of fatty acid calcium. The effect of calcium fatty acid on improving milk fat rate is closely related to the level of crude fiber in the feed. The ratio of energy and protein is an important factor affecting the production performance of animals. After adding fatty acid calcium, the energy increases and the ratio of energy to protein changes, which affects the production performance of animals accordingly. Experiments have shown that after adding fatty acid calcium, there is a tendency to reduce milk protein, so the adjustment of feed protein level should be considered, such as providing feed with high protein content or adding amino acids. Dietary energy level also affects the effect of fatty acid calcium. Generally, adding fatty acid calcium to high-energy diets has no obvious effect, or even has a negative effect.
Physiological conditions and environmental factors of animals. During the peak lactation period or heat stress in summer, the effect of using fatty acid calcium is better. In the late lactation period, when the energy is in a positive balance, the effect of supplementary feeding is not obvious. The effective effect of fatty acid calcium is limited to dairy cows with milk fat rate less than 3.5%, and the effect on high milk fat rate dairy cows is not obvious.
The addition amount of fatty acid calcium In general, the animal production performance tends to increase with the increase of the addition amount of fatty acid calcium, but if the addition amount is too much, the effect is not good, so the appropriate addition amount is very important for fatty acid calcium to play its role important. At present, there is no conclusion on the appropriate addition amount of fatty acid calcium, and further research is needed.
Questions to be further studied Although the application of calcium
fatty acid as an energy feed additive for ruminants is relatively common in foreign countries, the research mostly focuses on the effect of calcium fatty acid on animal production performance, and the impact of calcium fatty acid on animal physiological and biochemical indicators, research reports There is still very little, and research in this area should be strengthened. The appropriate addition amount is still inconclusive. In the future, it is necessary to carry out biological determination of the effective energy value of fatty acid calcium to determine the appropriate addition level. At the same time, through the comparative test of different types of fatty acid calcium, the fatty acid calcium products with stable performance and more in line with production needs were screened out.