EFFECT OF BODY CONDITION CHANGES ON SOME REPRODUCTIVE TRAITS IN HOLSTEIN-FRIESIAN AND BROWN SWISS COWS ,

Zhivka Gergovska, Juri Mitev, Teodora Angelova, Daniela Yordanova, Tchonka Miteva

Резюме: The study was carrying out with 32 cows, of which 17 Holstein and 15 Brown Swiss ones at the farm of the Agricultural Institute Stara Zagora. Cows from both breeds are reared together with the same technology and nutrition. The tearing technology is free rearing with individual cubicles for rest. Nutrition is based on full-ration mixture comprising maize silage, alfalfa haylage, concentrated fodder, vitamin and mineral additives. The body condition score (BCS) of cows has been recorded on a monthly basis by using a 5-grade scoring system and accuracy of recording up to 0.5 points. Mean BCS at calving for Brown Swiss cows is 3.12 points, while for the Holstein is 3.07. Holstein cows loss more points of BCS in the beginning of lactation (mean 2.13 points), and reached lower BCS (1.37) compared to Brown Swiss cows, in which these values are 1.88 and 1.68 points. Brown Swiss cows have shorter period to I-st insemination and days open (respectively 56.67 and 96.94 days) compared to Holsteins (60.8 and 135.1 days). Providing more body reserves at calving, corresponding to BCS 3.5 - 4 points, positively affects the reproductive traits in cows. They have shorter period to I-st insemination (50.25 days) and days open (94.0 days) compared to cows with lower degree of obesity. Cows reached lowest BCS lower degree of obesity during lactation, BCS 1 points, have worst reproductive traits, respectively longest period to I-st insemination - 73.4 days and days open - 147.27 days. Shortest are these periods in cows with minimum BCS 2 points, respectively 47.4 and 93.83 days. Cows with lowest loss of BCS after calving - 1 and less points, have shorter period to I-st insemination and days open, respectively 47.4 and 93.83 days compared to cows with losses over 1.5 points.

Ключови думи: body condition score; days open; loss of body reserves; minimum body condition score; period to I-st insemination

Дата на публикуване: 2023-03-01