With the intensive large-scale breeding of modern dairy cows and the continuous improvement of breeds, the production efficiency has been gradually improved, and the demand for various nutrients of dairy cows is also increasing, and the potassium in the mineral element nutrition is often neglected, which has an adverse impact on the health and production performance of dairy cows, resulting in a certain degree of economic loss.

The importance of potassium in dairy farming

It contains 1.5 g per kilogram of milk, which is the most abundant mineral element, and higher than 1 g of phosphorus and 1.2 g of calcium, it remains stable even in a state of heat stress. 25%-40% of the potassium intake of dairy cows directly enters the milk, a dairy cow with a daily output of 40kg needs at least 240g of potassium intake per day, but other physiological activities of dairy cows during the lactation period also need a large amount of potassium, such as insufficient supply will lead to a decline in lactation, long-term potassium deficiency will lead to a series of health problems such as excessive weight loss and poor development of mammary cells, resulting in a series of health problems such as excessive weight loss and poor mammary cell development, resulting in difficult recovery after the decline in milk production, or even elimination.

90% potassium is present in intracellular fluid, and in the resting state, the concentration of potassium ions in cells is 30 times higher than that outside cells. Potassium is involved in the acid-base balance, ion balance, and water balance in cells, and is involved in the formation of osmotic pressure as the body's most important electrolyte. The sodium-potassium pump existing in the cell membrane realizes the transport of proteins and other substances to the cell when the potassium ions are transported from the low concentration outside the cell to the high concentration in the cell, and the whole lactation process of the mammary gland cell is to continuously combine various substances such as protein into milk and output it to the milk pool. During the inverse delivery of potassium, a membrane point difference is formed at the same time, which is especially important for nerve conduction. In the animal body, potassium ions and calcium ions dominate the normal activities of muscles such as myocardium, calcium dominates contraction, potassium dominates diastole, too much and too little will cause the corresponding undesirable conditions, potassium excess will make the muscles in a relaxed state, that is, potassium inhibition, when potassium is insufficient, the cow's limbs are weak, lying on the ground, there are obvious muscle tremors and prolonged lying on the ground, difficulty swallowing, decreased appetite, and dyspnea occurs when the respiratory muscles are involved. However, it is safe to assume that due to the absorption and metabolism of potassium, it is difficult to cause an excess of potassium through food intake alone.

Potassium is stored in very small amounts in animals, and the metabolic characteristics of eating more and excreting more, and excreting without eating will excrete excess potassium through urine. 70% of the potassium in the body is stored in muscle cells, which itself maintains the normal osmotic pressure of the cells and maintains the normal volume of the cells, which is important for the maintenance of weight and the ionic balance of the cells. Therefore, potassium is a very depleted element in the cow's body. It is important to note that cows are more susceptible to potassium deficiency in two situations:

First, during heat stress in summer, due to the strong effect of renal tubular sodium conservation and potassium excretion, the amount of potassium excretion in urine increases, and the potassium lost through sweat also increases, and at the same time, the digestion and heat production of feed during heat stress and other factors cause a decline in dairy cow feed intake, which directly reduces the intake of potassium, and the decrease in potassium intake causes potassium insufficiency, which is more serious about the decline of feed intake, so a vicious circle. Therefore, in the case of heat stress, it is recommended to increase the potassium addition by 0.5%, which can effectively slow down the chain reaction caused by heat stress, and is more conducive to the recovery of yield after summer.

The second is when diarrhea occurs. Normally, cows excrete only 15%-25% of the total amount of potassium excreted in the faeces, but in the case of diarrhoea, the potassium excreted through the feces can be 10-20 times the normal value. Therefore, in the case of diarrhoea, it is also necessary to increase the potassium intake level so that the cow can recover more quickly.

In addition to reducing heat stress, potassium also has the effect of reducing cold stress and transport stress. Increasing potassium intake in calves in winter can improve calf survival. Feeding cattle with high potassium levels before transport can reduce mortality and transport weight loss during transportation, and can recover as soon as possible when they arrive at their destination.

Mechanism of action

By improving the electrolyte balance of the diet, it participates in maintaining the acid-base environment of body fluids, thereby regulating the activities of various enzymes in the body, alleviating various stress reactions, regulating animal endocrine, maintaining the homeostasis of the internal environment, and maximizing the production performance of the animal body.

1. Potassium is the third largest macroelement in the animal, and the fresh tissue of adult animals contains 0.18-0.27% potassium, and the storage of potassium in the body is very low, which must be continuously provided by feed.

2. Potassium is involved in sugar metabolism and protein metabolism in the body. Synthesis of 1 g of glycogen 0.15 mmol of potassium into the cell, synthesis of 1 g of protein resides in 0.45 mmol of potassium.

3. Potassium is the most abundant element in the muscle tissue of milk and beef cattle, and the most secreted in milk is potassium (1.5g of potassium per kilogram of milk, higher than 1.0g of phosphorus and 1.2g of calcium), and the content is extremely stable, and high milk yield and high growth rate need to ensure sufficient potassium supply.

4. Lactation diet, potassium concentration of 1.0-1.2% can ensure lactation supply, such as a small amount of potassium can be supplemented when the diet formula contains a large amount of licorice and silage pasture, such as a large amount of silage corn and grain dregs in the diet formula needs a large amount of potassium, in various stresses (cold stress, heat emergency, transportation stress, etc.), potassium should be supplemented, especially heat stress.

5. During heat stress, due to perspiration, animals lose 2-5 times more potassium.

6. The potassium contained in the raw materials of the diet is potassium chloride, potassium carbonate and potassium organic acid, which is quickly dissolved, absorbed, metabolized and discharged after entering the animal, which can meet a certain amount of potassium needs of the animal in this process, but cannot continue to supply potassium.

7. Potassium participates in the ion balance inside and outside animal cells to maintain the stability of the internal environment. At the same time, it plays a decisive role in the conduction of nerve signals. In the face of high production performance, animals are prone to sudden death during stress, and the cause of sudden death is mostly due to insufficient diastolic heart caused by potassium deficiency, and it remains in a state of contraction, unable to maintain normal blood circulation.

8. Potassium is also involved in regulating the activity of a variety of enzymes in the body, regulating animal endocrine, etc., and the comprehensive effect affects the performance of animals.