Relations of body condition score with milk yield and reproduction traits in Simmental cows
Özet
Introduction - Body condition score (BCS) is an important parameter to detect feeding regime and body energy reserves of animals and affects productivity of dairy cows. Recording BCS throughout lactation and eliminating effective environmental factors are essential processes for herd owners. Therefore, investigating the relationship between BCS and productivity characteristics is crucial for dairy sector. Aim - The objectives of this study were to determine the change of BCS and its relationship to milk yield and reproduction characteristics of Simmental cows. Material and methods - Milk yield and reproduction records of Simmental cows reared at Gokhoyuk state farm in Turkey, were used as study material. Milking cows were recorded by BCS at monthly intervals throughout a year. A scale of 1 to 5 with 0.25 increments was used to evaluate BCS (l=thin and 5=fat). Lactation length (LL), lactation milk yield (LMY), 305 day milk yield (305 DMY) and dry period (DP) were chosen as milk yield traits and calving interval (CI), days open (DO) and number of services per conception (NSC) were evaluated as reproduction traits. To provide data analysis, five groups for parity, three groups for stage of lactation (SL) and four groups for season were classified. While the Pearson correlation coefficients were estimated between BCS and the characteristics, all statistical analyses were performed using SPSS 13.0. Results and discussion - BCS means were 3.30 +/- 0.04, 3.40 +/- 0.03, 3.42 +/- 0.03 and 3.37 +/- 0.02 points for 70 +/- 14 d, 140 +/- 14 d, 210 +/- 14 d and entire lactation period, respectively. The lowest and highest BCS means (3.25 +/- 0.03 and 3.54 +/- 0.05) were determined in summer and winter, respectively. Lactation length (LL), lactation milk yield (LMY), 305 daily milk yield (305 DMY) and dry period (DP) were determined as 306.9 +/- 1.68 d, 5764.5 +/- 65.47 kg, 5700.4 +/- 59.95 kg and 66.6 +/- 0.91 d, and highest milk yield was obtained in the subgroup with BCS <= 3. Correlations between BCS and LL, LMY, 305 DMY and DP were estimated to be 0.004, -0.107, -0.115 and 0.002, respectively. Calving interval (CI), days open (DO) and number of services per conception (NSC) were 373.2 +/- 1.43 d, 92.8 +/- 1.46 d, and 1.96 +/- 0.05, and correlations of BCS with CI, DO and NCS were -0.007, - 0.004 and -0.007, respectively. Conclusion - Results of the present research demonstrate that BCS was lowest during summer and highest during winter. In early lactation period, cows tended to lose BCS. LMY and 305 DMY significantly (P< 0.05) affected by BCS. It was noticed that BCS <= 3 points ideal for higher milk production in Simmental cows. Exactly observing estrus cycle and decreasing insemination number per gestation to lower levels can be advised for dairy breeders as the profitable processes in the operations.
