| With the rapid development of animal husbandry, food consumption and the pollution of feces on the soil, water and air by livestock that become a barrier of green develop livestock. However, resource-saving and environment-friendly is the important for developing livestock. In recent years, with the development of intensive dairy industry in China, there are varieties diseases occur during the transition. Hypocalcemia of cows was one of the common nutritional and metabolic diseases. It was characterized with milk yield and the utilization rate of dietary decreased, and made a big economic loss. The effect of dairy cows with hypocalcemia on the production, utilization of dietary and discharge of feces was not clear. Thus, an experiment was made to studying the effect of dairy cows with hypocalcemia on the production, utilization of dietary and discharge of feces in the intensive dairy farm of Heilongjiang province, China. In order to provide a basic data for develop a green dairy industry.In test one, study on hypocalcemia and production performance of dairy cow in intensive dairy farm. Cows were selected by their body condition which tested within 30 d and closed parity in a Heilongjiang intensive dairy farm. They were divided into two groups according to concentration of serum calcium, hypocalcemia group(n=20) and healthy group(n=25) respectively. The basic information and clinical information of dairy cows were collected by using the electronic herd management system for analyzing the effect of dairy cows with hypocalcemia on the production. The results showed that the reproduction performance of cows with hypocalcemia was decreased, the first day in estrous, the days of first AI interval, the days of last AI interval and calving interval were significantly longer than healthy groups’(p<0.01); The number of AI of cows with hypocalcemia higher than healthy groups’(p<0.05); the lactation days of cows with hypocalcemia was significantly higher than healthy groups’(p<0.01), while the average daily milk production of hypocalcemia was significant lower than healthy groups’, it indicate that the milk production of cows with hypocalcemia was decreased. The cows with hypocalcemia are easily suffered the lameness, gastrointestinal diseases, mastitis, metritis and uterine infections. The mastitis was positively associated with hypocalcemia(p<0.01), and the uterine infections was also positively associated with hypocalcemia(p<0.05). In test two, study on the indication of blood, milk, feces and urine of cows with subclinical hypocalcemia. 12 cows were selected after calving 7-14 d in a Heilongjiang intensive dairy farm. They were divided into two groups according to concentration of calcium in serum, subclinical hypocalcemia group(n=6) and healthy group(n=6) respectively. The experimental period was 4 days. The parameters of blood, milk, feces and urine were detected for clarifying the metabolic characteristics of subclinical hypocalcemia cows. The results showed that: the concentrations of AST and TBIL of subclinical hypocalcemia group were significantly higher than the concentrations of healthy group(p<0.01). The CREA content of subclinical hypocalcemia group was significant higher than the concentration of healthy group(p<0.05). The concentrations of ALP, TP, TC were significantly lower than the contents of healthy group(p<0.01); the BHBA level of subclinical hypocalcemia group was significant higher than healthy group(p<0.05), and NEFA content of subclinical hypocalcemia group were higher than the healthy group(p<0.01). GLU concentration of subclinical hypocalcemia group was significantly lower than the healthy group(p<0.05); the contents of Ca, P and Mg in subclinical hypocalcemia group were significantly lower than the healthy group(p<0.01). The milk fat, milk protein and dry matter of subclinical hypocalcemia group were significantly higher than the healthy group(p<0.05); the acid detergent fiber of subclinical hypocalcemia group was significantly lower than the healthy group(p<0.05). The magnesium level of subclinical hypocalcemia group was significantly lower than the healthy group(p<0.05), the content of urinary protein of subclinical hypocalcemia group was significantly higher than the healthy group(p<0.05).In test three, study on the loss of energy and characteristic of feces discharge of subclinical hypocalcemia cows. 12 cows were selected in a Heilongjiang intensive dairy farm, China. They were divided into two groups according to the concentration of serum calcium and clinical manifestation, subclinical hypocalcemia group(n=6) and healthy group(n=6), respectively. Cows were kept separately for 4 days continuous, and the greenhouse gas emissions of cows was calculated by analyzing blood biochemical,milk production,feed intake, and amount of feces and urine emit and by a simple dynamic chamber technique for analyzing the emission of greenhouse gas of feces and urine. the results showed that the concentrations of calcium(Ca), inorganic phosphorus(P), magnesium(Mg) in serum of subclinical hypocalcemia group were significantly lower than the healthy group(p<0.01), β- hydroxybutyrate(BHBA) content of subclinical hypocalcemia group was significantly higher than health group(p<0.05), the concentrations of Non-esterified fatty acid(NEFA) of subclinical hypocalcemia group was significantly higher than health group(p<0.01), while the glucose content was significantly lower than health group(p<0.05); the milk yield, 4% Energy corrected milk(ECM) and feces output of subclinical hypocalcemia group were significantly higher than health group. There was no significantly difference on the digestively of dry matter between subclinical hypocalcemia group and health group. However, there was an increase tendency. The ammonia and carbon oxide emission was decreased, while there was no significantly difference, there was no significantly difference on the methane emission.Conclusion: milk production performance and reproductive performance of cows with hypocalcemia were decreased. The cows with hypocalcemia were easier to suffered mastitis and uterine infection. It made a serious economic loss for dairy farm. Cows with hypocalcemia were in energy negative balance, which was characterized with abnormal of liver function and mineral, enhancement of intestinal digestion and absorption function and renal dysfunction. Emissions of NH3 and CO2 from feces of subclinical hypocalcemia cows were lower than healthy cattle. However, it needs to study further for clearing the relationship with reduced greenhouse gas emission and the intestinal digestion, intestinal absorption and absorption of feed energy.
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