Browsing by Author "Soydaner M."

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Association of change in body condition score with milk yield and reproduction traits of holstein cows
(2020-04-01) Kul E.; Şahin A.; Uğurlutepe E.; Soydaner M.
The aim of the study was to determine the effect of changes in body condition score (BSC) on milk yield and reproduction traits in early (30, 60 and 90 d), mid (120 and 150 d) and late lactation (210 and 270 d) in Holstein cows raised on a private dairy cattle farm in Kırşehir, Turkey. The data were obtained from 140 cows calved from November 2014 to November 2015. BSC groups were categorized as low, moderate and high in early lactation (<2.75, 2.75–3.00 and >3.00), mid-lactation (<3.00, 3.00–3.25 and >3.25) and late lactation (<3.25, 3.25–3.50 and >3.50). Cows with low and moderate BCS in early (BCS<2.75 and BCS=2.75-3.00), mid (BCS<3.00 and BCS=3.00–3.25) and late lactation (BCS<3.25 and BCS>3.50) had a higher daily milk yield (DMY), lactation milk yield (LMY) and 305-day milk yield (305-dMY) (P<0.05). Reproduction traits were also affected (P<0.05) by BCS in mid-lactation. In mid-lactation, the cows with low and moderate BCS had a shorter period of calving to the first service interval (CFSI) and lower number of services per conception (NSC) than that of the cows with high BCS (P<0.05). Both milk yield and reproduction traits were adversely affected by high BCS. It is suggested that BCS can be used as a reliable indicator in indirect selection programs for higher milk yield and reproductive performance in Holstein cows.
Estimation of genetic and phenotypic parameters for body condition score, milk yield and milk composition, and factors affecting related traits during the first 150 days of lactation in Holstein cows
(2022-01-01) Kul E.; Şahin A.; Uğurlutepe E.; Soydaner M.; Abaci S.H.
This study aimed to estimate the genetic and phenotypic parameters for BCS, milk yield and its composition in Holstein cows. The data were collected in the first 150 days in milk (DIM) of 317 Holstein cows calved between 2017 and 2018 raised at a pri-vate dairy cattle farm located in Kırşehir of Turkey. In this study, parity and DIM were included as fixed factors in the model. The cows were grouped according to their BCS: low (BCS≤2.50), moderate (BCS=2.75-3.00) and high (BCS≥3.25). The results showed that effects of parity and DIM on BCS, test-day milk yield (TDMY), solids-non-fat (SNF), protein content (PC), lactose (LACT), fat yield (FY) and protein yield (PY) were significantly important (P<0.05), whereas fat content (FC) was not. The highest TDMY, FY and PY were determined in cows with low BCS. FC, SNF, PC and LACT were the highest in cows with high BCS compared to those with low BCS and moderate BCS. The estimated heritability were 0.188, 0.301, 0.184, 0.197, 0.194, 0.223, 0.196 and 0.342 for BCS, TDMY, FC, SNF, PC, LACT, FY and PY, respectively. Repeatability for these traits was estimated to vary from 0.257 to 0.521. Genetic correlations between BCS and milk yield traits were generally low and ranged from-0.175 to 0.191. Low to moderate phenotypic correlations were also observed between BCS and milk yield traits (-0.234 to 0.217). Despite estimated low heritability and correlations during the early lactation period in our study, these results showed that cows with lower BCS had higher milk yield and lower milk contents, and selection programs including BCS will lead to slight improvements of milk yield traits in Holstein cows.