The production of milk fat is related to the substances that come to the breast from two sources. These substances are acetic acid produced as a result of microbial digestion in the rumen and the fats in the feed are digested and pass into the blood. Acetic acid, which is produced in the rumen and passes into the blood, and fatty acids circulating in the blood, come to the breast tissue through the blood and participate in the formation of milk fat. Therefore, the more fat and/or acetic acid in the blood, the more milk fat is produced. As a result of the digestion of feed materials in the rumen, volatile fatty acids, including acetic acid, are synthesized. The amount of acetic acid involved in the production of milk fat is affected by nutrition. The more dietary fiber, that is, cellulose-rich feed material, is given to the animal, the more acetic acid is produced. Cellulose is mostly found in roughage. For this reason, increasing the amount of roughage in the ration causes an increase in the fiber, that is, the cellulose ratio, and thus the acetic acid amount. Increasing the roughage ratio does not increase milk fat only by increasing the amount of acetic acid. At the same time, by giving roughage, the animal is provided to ruminate more. Rumination increases saliva secretion and this secretion is swallowed and comes to the rumen. Saliva has an alkaline pH of 8.4. Acid (volatile fatty acids) is produced in the rumen as a result of the digestion of carbohydrates, especially starch. These acids lower the pH of the rumen. When the acidity increases, especially the bacteria that digest cellulose, begin to die. With the death of these bacteria, this time acetic acid production decreases and milk fat decreases. Ideally, roughage should be at least 50% in high-yielding dairy cow rations.
When the cellulose in the roughage is digested well, more acetic acid is produced. Thus, it is expected to be more effective on milk fat with more acetic acid production. However, in herds using a high amount of concentrated feed, small amounts of poor quality roughage such as straw, which stimulates rumination more because of its difficult digestibility rather than the roughage quality, may contribute more to milk fat.
Digestion in the rumen increases as the grinding size of some concentrate feeds decreases, especially starch-rich cereals such as corn or barley. As a result of this increase, more acid is produced in the rumen. As a result of this increased acidity, fiber digestion and milk fat are indirectly reduced. However, attempting to coarsely grind the grains due to the incident occurring here also leads to a decrease in digestion. This reduces exploitation. Therefore, it is still best to finely grind the grains or subject them to special treatments that increase rumen digestion, such as flaking.
Studies have shown that as the chop size of the roughage decreases, rumination decreases and accordingly, less saliva is produced for buffering the rumen. For this reason, roughage should not be finely chopped. However, when the feed-eating behavior of the animals was examined, it was observed that the ration placed in front of them made a feed selection behavior in favor of small pieces. Therefore, coarsely chopping the roughage seems to be a correct method on paper, but the desired result will not be obtained if the animals do not consume by choosing the feed. Therefore, the shredding size should not be reduced too much, but it should not be kept too large.
It is very natural to expect milk fat to increase indirectly as the cellulose ratio in the rations increases. While making the arrangements, it is necessary to act by controlling the milk yield. Because cellulose is a nutrient that is digested slower and less than starch and sugar, and therefore has a lower energy. Since excessive cellulose increase will reduce ration consumption and energy too much, a decrease in milk yield should be expected.
As the amount of starch and sugar in the concentrated feed increases, there will be more acid production in the rumen, and milk fat may be adversely affected by this situation.
Studies on dairy cows have shown that with increasing feeding frequency, there is less feed selection behavior, and therefore milk fat is positively affected by this situation. Feeding frequency in dairy cows should be at least twice a day.
Sodium bicarbonate, magnesium oxide and similar feed additives often have positive effects in increasing milk fat. These substances exert their effects by preventing the decrease of the pH of the rumen and indirectly by serving more fiber degradation.
Young meadow and pasture grasses often have low cellulose content. For this reason, grazing in meadows and pastures as a source of roughage instead of roughage such as hay, hay, hay may lead to a decrease in milk fat by leading to less but more digestible fiber intake, less rumination.
Excessive decrease in the protein level of the ration leads to a decrease in milk protein. On the contrary, when the amount of amino acids such as methionine and lysine increases in the diet, milk protein increases. Adding bypassed lysine and methionine to diets or using raw materials with such properties can increase milk protein.
The inclusion of fractionated type oils containing fatty acids with high palmitic content in the rations may positively affect milk fat, but may lead to a decrease in milk protein.
