Interrelationship between biochemical indices of milk and blood of dairy cows in the second and fourth month of lactation depending on milk yield | Piena un asiņu bioķīmisko rādītāju kopsakarības govīm otrajā un ceturtajā laktācijas mēnesī atkarībā no izslaukuma

This publication is an extension of the previous experiment described in the proceedings of International scientific conference 'Animals. Health. Food hygiene' in Jelgava 14 Nov. 2008 [11]. The aim of the study was to investigate: 1) the interrelationship of biochemical indices of milk and blood of high and low productive cows with unified nutrition; 2) dependence of correlative interrelationship among biochemical indices of analyzed samples; 3) the usefulness of correlations among biochemical indices to control the quality and health of dairy cows. The experiment was carried out during indoor period in one 70 cow heard, with unificied nutrition. There were selected five high productive cows and nine low productive cows in the second month of lactation (30-60 days in milk). All milk and blood samples were collected 2 times: in the second (I) and the fourth (II) month of lactation for the monthly milk quality control (interval 62 days). Biochemical indices of milk and blood samples were statistically analyzed by SPSS 11,5. The mean milk yield in the group of high productive cows I was 30.68+-1.40 kg/day (26.50 to 35.00 kg/day), but in the group of low productive cows I - 18.34+-0.59 kg/day (15.10 to 20.00 kg/day). The mean milk yield after two months II was decreased significantly to 16.40+-0.97 kg/day in the group of high productive cows and to 13.83+-0.63 kg/day in the group of low productive cows. The mean urea concentration in milk decreased more than two times in both groups of productivity. The mean fat and protein percentage in milk was below average results in both groups of productivity. Health problems of cows were: subclinical acidosis, hepatosis, dehidratation, high SCC. There were established 12 correlations in the group of high productive cows and 11 correlations in the group of low productive cows between the milk yield, somatic cell count (SCC), milk components (protein %, fat %, urea) and blood biochemical indices (total protein, albumin, urea, GGT, cholesterol, triglycerides, fibrinogen). These correlations depended on nutritional, health status, productivity of cows in the heard and number of analysed samples.