Osteomalacia of dairy cows is a chronic nutritional metabolic disease, which is caused by the lack of calcium, phosphorus or the unreasonable ratio of the two feedstuffs, resulting in the disorder of calcium and phosphorus metabolism and bone decalcification. The main clinical features are digestive disorders, soft bones, deformed hoofs, abnormal limbs, and lameness. If not treated properly, it will lead to the decline or total loss of cow production capacity, which will have an impact on cow production and development. Next, let's get to know: the etiology of osteomalacia in dairy cows, the clinical symptoms of osteomalacia in dairy cows and the prevention and treatment measures.
Feeds are deficient in calcium, phosphorus, and vitamin D. Normally, milk cows consume 1.2g of calcium and 0.8g of phosphorus per kg of lactation. Taking 20 kg of lactation as an example, the daily loss of calcium and phosphorus due to lactation reaches 24g and 16g, respectively. Also, the daily requirement of calcium and phosphorus for maintaining the physiological activities of dairy cows is 20g and 15g. According to the fact that dairy cows can absorb 22% - 55% of the calcium in feed, a dairy cow with 20 kg of milk per day needs to absorb more than 120 g of calcium and 83 g of phosphorus per day. If the content of calcium and phosphorus in dairy cattle feed is below this standard, the calcium and phosphorus stored in the skeleton will be mobilized to maintain the physiological activity and lactation requirements of the body, thus causing the occurrence of the disease. Also, if the diet contains less vitamin D, it will lead to the body's ability to absorb calcium and phosphorus in the diet, thus causing the disease.
The proportion of calcium and phosphorus in feed is not appropriate. For adult dairy cows, 38% of bone ash is calcium, 17% is phosphorus, that is, the ratio of calcium to phosphorus is 2:1. Therefore, the ratio of calcium to phosphorus in the diet should be close to the ratio of calcium to phosphorus in the bone, that is, to control it at 1-2:1. If we do not pay attention to the preparation, which leads to too much phosphorus, too little calcium or too much calcium, too little phosphorus, can also lead to insufficient calcium and phosphorus, thus causing the disease.
Certain diseases. When cows have hyperparathyroidism, numerous calcium salts in the skeleton will dissolve and cause the disease. Dairy cows suffer from the liver abscess and fatty liver, which can affect the activation of vitamin D, thus inhibit calcium and phosphorus absorption, and affect the osteogenesis, and subsequently cause the disease. Dairy cow kidney dysfunction can accelerate calcium excretion from the kidney, which can cause the disease. Dairy cows suffer from chronic digestive tract diseases, which will directly affect the absorption of calcium and phosphorus, and then cause the disease.
Other factors. Genetic factors and age also affect calcium and phosphorus uptake in dairy cows. Also, low temperature, high feeding density, and poor ventilation will lead to changes in the amount of calcium and phosphorus required. The presence of calcium and phosphorus antagonists or high concentration of fluoride in drinking water and feed can lead to the influence of calcium absorption and abnormal bone metabolism.
In the beginning, the diseased cattle only showed chronic indigestion, reduced intake and drinking water, poor spirit, heterophilia, such as eating bricks, soil and so on. Feces are thinner and drier, mixed with undigested feed. Then refuse to stand or difficult to stand, abdomen curled, back stiff, often lying on the ground, accompanied by a limp or several limbs, and generally metastatic. When the illness is serious or light, it is easy to fatigue, accompanied by severe pain, and eventually paralyzed to the ground. Most of them can only be eliminated because they are prone to fall or fracture during exercise. Also, the body temperature, respiration, and pulse of the diseased cattle were normal in the initial stage, but the heart rate accelerated in the later stage, reaching 70-80 beats/min, and the heart sound was turbid. Also, if the sick cattle lie on the ground for a long time, they will often have complications, such as bedsores, and the prognosis is poor.
Western medicine treatment. Calcium carbonate, stone powder or calcium citrate powder should be added to the diet of dairy cows to ensure that the amount of calcium and phosphorus fed every day during dry milk period is at least 55 g and 22 g. In the lactation period, the amount of calcium and phosphorus Fed is determined according to the amount of lactation, which generally requires 2.5 g of calcium and 1.8 g of phosphorus per kilogram of milk. The diseased cattle can be injected intravenously with 500-1000 ml 20% calcium gluconate injection or 100-200 ml 10% calcium chloride injection for 3-5 consecutive days for calcium supplementation. In the diet of diseased cattle, 30-100g sodium phosphate and 250g tricalcium phosphate can be added, and 500 ml 20% sodium dihydrogen phosphate injection can be intravenously injected once a day for 3-5 days for a course of treatment. To enhance the absorption and utilization of calcium and phosphorus in the intestinal tract, an intramuscular injection of 5-10mL vitamin AD injection or 5-20 mL vitamin D2 gelatinous calcium (vitamin D2 gelatinous calcium) injection can be administered once a day at intervals of 3-5 days for a course of treatment.