Evaluation of gestation length and birth weight of offspring of Polish native cattle breeds in context of estimating genetic parameters

Abstract

Research material included data on gestation length of 15 436 cows of Polish native breeds. These were: White Backed (BG; 324 records), Polish Red (RP; 5396 records), Polish Black and White (ZB; 3508 records), and Polish Red and White (ZR; 6208 records). The calvings took place in 2005–2009, and we analysed two calving seasons, lactation number, the degree of calving difficulty, sex, and body weight of newborn calves. The effect of birth year on gestation length and birth weight of offspring was statistically significant, whereas calving season had statistically highly significant effect on both. Gestation length in the analysed breeds was 281.02, 283.35, 280.5, 281.53 for BG, RP, ZB, and ZR, respectively. The birth body weight heritability was 0.13 (RP), 0.33 (ZB) and 0.40 (ZR).