RESUMO
In dairy farming, the productive performance of lactating cows is directly related to the efficiency of the production system. In this respect, studies in different areas investigating animal production try to understand the determinant factors of milk production. Many studies have shown a high correlation between milk production of cows and performance of their calves; however, few studies have addressed the influence of calf sex on milk production. With the objective to evaluate the influence of fetal sex on the milk production of Holstein cows, the present study analyzed cumulative milk yield data provided by the Agrindus Farm in Descalvado, São Paulo. A total of 10,780 calvings of 4,807 cows that had calved between April 2001 and October 2013 and their cumulative yields during lactation according to offspring sex were evaluated. The PROC GLM procedure of the SAS software (SAS Inst., Inc., Cary, NC) was used for analysis. The contemporary group was defined as year and month of calving, with a minimum of 5 observations per group. In addition to contemporary group, the effects of management group and calving order of the cow were included in the model. Mean cumulative yields were 9,800.79 and 9,802.95 kg for cows that had given birth to males and females, respectively. There was no significant difference (P=0.9519) in cumulative milk yield of cows during the study period as a
O artigo não apresenta resumo em português.
RESUMO
The body weight (BW) determination is important to evaluate the growth of animals, their nutritional condition and reproduction and to establish the slaughter time and the sale value of the animal. The chest girth (CG) could be an alternative to determine the body weight of sheep on properties that do not have scales. The objective of this study was to investigate the feasibility of using chest girth to determine the estimated body weight (EBW). The data file contained 1762 records of body weight (BW) and chest girth (CG) from 426 Santa Ines breed sheep, belonging to eight herds located in Southeastern Brazil. The chest girth was measured using the sternum and the withers as base, passing the tape measure behind the shoulder. Body weights were related to CG values through linear regressions using the software Statistical Analysis Systems (SAS Inst., Inc., Cary, NC). The age classes 1, 2, 3, were defined respectively as: 0 to 12 months; 13 to 22 months; over 34 months. The regression equation used to predict the body weight through chest girth in different age classes was y = b0 + b1x, where y is the dependent variable EBW, x is the independent variable CG, b0 is the intercept, b1 is the slope of the equation that defines the relationship between EBW and CG. The other variables were constant. The regression equations for specific age groups of animals were: Class 1 EBW = -42.201
O artigo não apresenta resumo em português.
RESUMO
The body weight (BW) determination is important to evaluate the growth of animals, their nutritional condition and reproduction and to establish the slaughter time and the sale value of the animal. The chest girth (CG) could be an alternative to determine the body weight of sheep on properties that do not have scales. The objective of this study was to investigate the feasibility of using chest girth to determine the estimated body weight (EBW). The data file contained 1762 records of body weight (BW) and chest girth (CG) from 426 Santa Ines breed sheep, belonging to eight herds located in Southeastern Brazil. The chest girth was measured using the sternum and the withers as base, passing the tape measure behind the shoulder. Body weights were related to CG values through linear regressions using the software Statistical Analysis Systems (SAS Inst., Inc., Cary, NC). The age classes 1, 2, 3, were defined respectively as: 0 to 12 months; 13 to 22 months; over 34 months. The regression equation used to predict the body weight through chest girth in different age classes was y = b0 + b1x, where y is the dependent variable EBW, x is the independent variable CG, b0 is the intercept, b1 is the slope of the equation that defines the relationship between EBW and CG. The other variables were constant. The regression equations for specific age groups of animals were: Class 1 EBW = -42.201
O artigo não apresenta resumo em português.
RESUMO
In dairy farming, the productive performance of lactating cows is directly related to the efficiency of the production system. In this respect, studies in different areas investigating animal production try to understand the determinant factors of milk production. Many studies have shown a high correlation between milk production of cows and performance of their calves; however, few studies have addressed the influence of calf sex on milk production. With the objective to evaluate the influence of fetal sex on the milk production of Holstein cows, the present study analyzed cumulative milk yield data provided by the Agrindus Farm in Descalvado, São Paulo. A total of 10,780 calvings of 4,807 cows that had calved between April 2001 and October 2013 and their cumulative yields during lactation according to offspring sex were evaluated. The PROC GLM procedure of the SAS software (SAS Inst., Inc., Cary, NC) was used for analysis. The contemporary group was defined as year and month of calving, with a minimum of 5 observations per group. In addition to contemporary group, the effects of management group and calving order of the cow were included in the model. Mean cumulative yields were 9,800.79 and 9,802.95 kg for cows that had given birth to males and females, respectively. There was no significant difference (P=0.9519) in cumulative milk yield of cows during the study period as a
O artigo não apresenta resumo em português.