D. Yordanova*, T. Angelova, J. Krastanov, D. Miteva, V. Karabashev, G. Kalaydzhiev
Agricultural institute, 6000 Stara Zagora, Bulgaria
(Manuscript received 10 July 2020; accepted for publication 16 September 2020)
Abstract. The aim of the study was to evaluate the differences in milk coagulation properties in three groups of dairy cows receiving the dietary supplements Panamin Animal and Panamin Detox. The present group production experiment was conducted in the experimental cattle farm of the Agricultural Institute – Stara Zagora with three groups (two experimental and one control) each comprising 11 lactating dairy cows between November 2016 and March 2017. The cows are kept freely, the milking is in a hall “Fish bone”, and the groups were fed balanced rations compliant with milk yield and live body weight of cows, supplemented with 0.50 g/day of two natural dietary additives – Panamin Animal and Panamin Detox in line with recommendations of the manufacturer. The following parameters were monitored: rennet coagulation time (min) – RCT and curd firmness (mm) – a30. The analysis of individual milk coagulation properties was done on 436 milk samples from cows. Individual milk samples were obtained during the morning milking without adding preservative. The analysis of milk coagulation ability was evaluated at the laboratory of the Agricultural Institute – Stara Zagora by means of Computerized Renneting Metter – Polo Trade, Italy. The obtained phenotypes were corrected for main factors influencing test-day milk yield. The used model considered each test day milk yield as independent observation and unbiased estimates of traits were obtained by a linear mixed-effects model. The supplementation of cows’ ration with dietary supplements Panamin Detox and Panamin Animal had a statistically significant beneficial effect on milk coagulation properties of milk (p<0.001). The statistical analysis of group differences in RCT and curd firmness showed highly significant differences between Panamin Animal and control groups for both traits (p<0.001). There was also a highly relevant difference in curd firmness of milk from cows given Panamin Detox supplement and control cows (p<0.001). Data were processed with statistical software products Systat 13 and Pest (Groeneveld), and graphs were generated in MS Excel.