RESUMEN
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.
RESUMEN
Performance evaluation of adapted animals to local conditions for economic traits is essential for the preservation of species and their genetic resources. The size of Morada Nova breed herds have decreased over time, becoming restricted to a few regions. Other races have been used with higher frequency because of their production and adaptation, and are important as a source of food and income for local communities. The objective of this research was to evaluate the application of nonlinear models to describe the growth curve of Morada Nova sheep. Records of 1604 weights of 250 lambs from Nova Odessa municipality, being 934 repeated measurements of female and 670 repeated measurements of male, obtained between 2012-2013 were used. The average birth weight observed was 2.50 ± 0.690 kg. The nonlinear models used to adjust the data were Brody Yt = A (1 - be-kt); Von Bertalanffy Yt = A (1 - be-kt)3; Richards Yt = A (1 - be-kt)m; Logistic Yt = A (1 + e-kt)-m and Gompertz Yt = Ae -be(-kt). The models were fitted by Gauss-Newton using the NLIN procedure of SAS (SAS Inst., Inc., Cary, NC). The parameters that make up the functions are Y = body weight at the age t; A = asymptotic weight that represents the average adulthood weight; K = Maturation rate, an indicator of the speed with which the animal approaches its adult size, maturity of the individual in relation to age is the fractio
O artigo não apresenta resumo em português.
RESUMEN
Performance evaluation of adapted animals to local conditions for economic traits is essential for the preservation of species and their genetic resources. The size of Morada Nova breed herds have decreased over time, becoming restricted to a few regions. Other races have been used with higher frequency because of their production and adaptation, and are important as a source of food and income for local communities. The objective of this research was to evaluate the application of nonlinear models to describe the growth curve of Morada Nova sheep. Records of 1604 weights of 250 lambs from Nova Odessa municipality, being 934 repeated measurements of female and 670 repeated measurements of male, obtained between 2012-2013 were used. The average birth weight observed was 2.50 ± 0.690 kg. The nonlinear models used to adjust the data were Brody Yt = A (1 - be-kt); Von Bertalanffy Yt = A (1 - be-kt)3; Richards Yt = A (1 - be-kt)m; Logistic Yt = A (1 + e-kt)-m and Gompertz Yt = Ae -be(-kt). The models were fitted by Gauss-Newton using the NLIN procedure of SAS (SAS Inst., Inc., Cary, NC). The parameters that make up the functions are Y = body weight at the age t; A = asymptotic weight that represents the average adulthood weight; K = Maturation rate, an indicator of the speed with which the animal approaches its adult size, maturity of the individual in relation to age is the fractio
O artigo não apresenta resumo em português.
RESUMEN
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.
RESUMEN
In a sheep production system, the growth-related characteristics have direct relationship to both, quantity and quality of meat. The objective of this study was to evaluate the application of non-linear models to report the growth curve of Santa Inês sheep. Weights of 140 females, born from2010 to 2012, from a single herd at Cravinhos- SP were used. The weights were measured from birth to about one year of age and the ages were grouped together in biweekly classes. The average weight observed at birth was of 3.77±0.92 kg. The non-linear models utilized in the data adjustment were the Brody, Gompertz, Logistic and Von Bertalanffy models, adjusted by the Gauss-Newton method by means of NLIN procedure, available in SAS software. The parameters which compose the functions, Wt (kg) is the weight in time t (days); A (kg) is the asymptotic weight when age tends to infinity; b is an integration constant, related to the initial weights of the animals and not well defined biological interpretation, and k is the maturity rate. The average estimates for A and k, are the most important from an zootechnical parameters point of view, mainly because heavier females tend to create faster growing sheep. All the models evaluated reached convergence. The quality of the models adjustment was done by error mean square (EMS) means. From the EMS results , the Gompertz model showed the best adjustment,
O artigo não apresenta resumo em português.
RESUMEN
The objective of this study was to evaluate the frequency of clinical mastitis (CM), in high production Holstein cows, as well as the environmental factors that favoring its incidence. The average milk production of 305 days, according to the class of mastitis was estimated by the method of least squares. The frequencies of clinical mastitis (CM) events were analyzed according to the calving sequences (1-6), year of calving, season and stage of lactation, and infected quarter (right anterior, left anterior, right posterior, left posterior). The frequency of CM ranged from 11.39% in the first calving to 21.18% in the third. 58.56% of mastitis cases occurred in the wet season, and 41.44% occurred in the dry season. The final lactation stage (200 to 300 days) was the period with the highest occurrence of CM (45.33%). The quarter posterior had a higher frequency CM (54.25%). Animals with higher levels of milk production of 305 days showed highest occurrence of CM. We must find a balance between milk production and mastitis in order to increase profitability. The study of the periods of greatest frequency clinical mastitis events is essential for dairy farming, to direct a program to control this disease.
O objetivo deste estudo foi verificar as frequências de mastite clínica (MC) em vacas Holandesas de alta produção de leite, bem como os fatores ambientais que influenciam sua incidência. A média da produção de leite aos 305 dias de acordo com a classe de mastite foi estimada pelo método de quadrados mínimos. As frequências de MC foram analisadas de acordo com as ordens do parto (1 a 6), ano do parto, estação do ano, fase da lactação, e quarto infectado (anterior direito, anterior esquerdo, posterior direito, posterior esquerdo). A frequência da MC por ordem de parto variou de 11,39% no primeiro parto a 21,18% no terceiro parto. 58,56 % dos casos de mastite ocorreram no período das águas e 41,44% no período da seca. O terço final da lactação foi o período com maior ocorrência de casos de MC (45,33%). Os quartos posteriores apresentaram maior frequência de MC (54,25%). Os animais com maiores níveis de produção de leite aos 305 dias (9.466,42 Kg) foram os que apresentaram maior incidência de mastite clínica. Deve-se encontrar um ponto de equilíbrio entre a produção de leite e a mastite a fim de aumentar a rentabilidade da produção. O estudo dos períodos de maior frequência de ocorrência de mastite clínica é fundamental para a pecuária leiteira, para o direcionamento de um programa de controle dessa doença.
RESUMEN
In a sheep production system, the growth-related characteristics have direct relationship to both, quantity and quality of meat. The objective of this study was to evaluate the application of non-linear models to report the growth curve of Santa Inês sheep. Weights of 140 females, born from2010 to 2012, from a single herd at Cravinhos- SP were used. The weights were measured from birth to about one year of age and the ages were grouped together in biweekly classes. The average weight observed at birth was of 3.77±0.92 kg. The non-linear models utilized in the data adjustment were the Brody, Gompertz, Logistic and Von Bertalanffy models, adjusted by the Gauss-Newton method by means of NLIN procedure, available in SAS software. The parameters which compose the functions, Wt (kg) is the weight in time t (days); A (kg) is the asymptotic weight when age tends to infinity; b is an integration constant, related to the initial weights of the animals and not well defined biological interpretation, and k is the maturity rate. The average estimates for A and k, are the most important from an zootechnical parameters point of view, mainly because heavier females tend to create faster growing sheep. All the models evaluated reached convergence. The quality of the models adjustment was done by error mean square (EMS) means. From the EMS results , the Gompertz model showed the best adjustment,
O artigo não apresenta resumo em português.
RESUMEN
The crossbreeding practice between specialized dairy breeds is an usual method for dairy producers and recently the Holstein x Jersey crosses has continuously increased in some regions of Brazil. Motivating factors of this practice include an interest in improving the milk solids content, somatic cell count (SCC), fertility, longevity and calving ease, in addition to reduce the problems of consanguinity. The aim of this paper was to evaluate the milk components and milk yield of Holstein x Jersey crosses. Data set comprised 59,331 monthly records of 6,429 pure Holstein (H) and Jersey (J) and ½ H x ½ J crossed cows calving from 1992 to 2010. The traits analyzed were test-day milk yields (MT), somatic cell score (SCS) and percentages of fat (%F) and protein (%P). Since the SCC is not normal distributed it was converted to a logarithmic scale in SCS, using the following equation, SCS = log2 (SCC/100) + 3. The variables MT, SCS, %F and %P were analyzed as dependent variables by least square method using GLM procedure. There were considered linear models containing the effects of breed (H, J and ½ H x ½ J or F1), herd, year and month of test as classificatory variables. Age at calving (AC) and days in milk (DM) were included as covariates (linear and quadratic effects) for all traits. The test-day milk yield was included as covariate for SCS model, %F and %P. All variables included
O artigo não apresenta resumo em português.
RESUMEN
The milk yield has been the most selected trait in dairy cattle breeding programs. However various studies have shown a decline in adaptive and longevity traits in herds that are under selection for improving production, especially in taurine breeds, as the Holstein, who was highly selected for milk production. The aim of this study was to estimate genetic parameters for first lactation 305-day milk yield (Y305) and for longevity traits and to verify the association among them, in high production Holstein cows. The data sets used were from Agrindus Farm, with calving occurring between 1989 and 2005. The traits analyzed were Y305, productive life (PL), calculated as the length of lactation days from the first day of lactation until the culling, and age at culling (AC). Variance components were estimated by Restricted Maximum Likelihood, applying multi-trait animal model. Heritability estimates for Y305, PL and AC were, respectively, 0.35, 0.07 and 0.10. Heritability estimates for PL and AC suggest small genetic variability to get genetic gains by direct selection for these traits, because they are influenced by decisions of voluntary and involuntary culling, being largely affected by factors related to the environment. It is difficult to measure these traits because it is necessary to evaluate culling of animals and causes of culling. The magnitude of the heritability estimate f
O artigo não apresenta resumo em português.
RESUMEN
For dairy cattle breeds, mainly the taurine ones, the selection emphasized for many years the increase in milk yields and, as a consequence, the adaptive and reproductive traits were negatively affected. The aim of this study was to verify the influence of genetic and environmental effects on the reproductive traits in a dairy herd selected for high milk production levels. The data set comprised 1,737 first lactations Holsteins cows of Agrindus Farm, located at Southeastern region of Brazil. The records of the following reproductive traits: calving to first heat interval (CFHI), calving to conception interval (CCI) and first to second calving interval (FCI) were analyzed as dependent variables by least squares method using GLM procedure (SAS). Linear models were considered including two production levels (1= less than 9,500 kg and 2= more than 9,501 kg of total milk yield), contemporary group (year and months calving), management group, sire of cow, and the sire used to breeding cows, as classificatory variables. As covariates were included for all traits the peak milk yield in lactation (linear effect), age at calving only for CFHI (linear and quadratic effects) since this effect was not significant for other traits, and CFHI (linear effect) only for FCI. The coefficients of determination represented 24%, 74% and 75%, respectively for CFHI, FCI and CCI models. Production level
O artigo não apresenta resumo em português.
RESUMEN
For dairy cattle breeds, mainly the taurine ones, the selection emphasized for many years the increase in milk yields and, as a consequence, the adaptive and reproductive traits were negatively affected. The aim of this study was to verify the influence of genetic and environmental effects on the reproductive traits in a dairy herd selected for high milk production levels. The data set comprised 1,737 first lactations Holsteins cows of Agrindus Farm, located at Southeastern region of Brazil. The records of the following reproductive traits: calving to first heat interval (CFHI), calving to conception interval (CCI) and first to second calving interval (FCI) were analyzed as dependent variables by least squares method using GLM procedure (SAS). Linear models were considered including two production levels (1= less than 9,500 kg and 2= more than 9,501 kg of total milk yield), contemporary group (year and months calving), management group, sire of cow, and the sire used to breeding cows, as classificatory variables. As covariates were included for all traits the peak milk yield in lactation (linear effect), age at calving only for CFHI (linear and quadratic effects) since this effect was not significant for other traits, and CFHI (linear effect) only for FCI. The coefficients of determination represented 24%, 74% and 75%, respectively for CFHI, FCI and CCI models. Production level
O artigo não apresenta resumo em português.
RESUMEN
The milk yield has been the most selected trait in dairy cattle breeding programs. However various studies have shown a decline in adaptive and longevity traits in herds that are under selection for improving production, especially in taurine breeds, as the Holstein, who was highly selected for milk production. The aim of this study was to estimate genetic parameters for first lactation 305-day milk yield (Y305) and for longevity traits and to verify the association among them, in high production Holstein cows. The data sets used were from Agrindus Farm, with calving occurring between 1989 and 2005. The traits analyzed were Y305, productive life (PL), calculated as the length of lactation days from the first day of lactation until the culling, and age at culling (AC). Variance components were estimated by Restricted Maximum Likelihood, applying multi-trait animal model. Heritability estimates for Y305, PL and AC were, respectively, 0.35, 0.07 and 0.10. Heritability estimates for PL and AC suggest small genetic variability to get genetic gains by direct selection for these traits, because they are influenced by decisions of voluntary and involuntary culling, being largely affected by factors related to the environment. It is difficult to measure these traits because it is necessary to evaluate culling of animals and causes of culling. The magnitude of the heritability estimate f
O artigo não apresenta resumo em português.
RESUMEN
The crossbreeding practice between specialized dairy breeds is an usual method for dairy producers and recently the Holstein x Jersey crosses has continuously increased in some regions of Brazil. Motivating factors of this practice include an interest in improving the milk solids content, somatic cell count (SCC), fertility, longevity and calving ease, in addition to reduce the problems of consanguinity. The aim of this paper was to evaluate the milk components and milk yield of Holstein x Jersey crosses. Data set comprised 59,331 monthly records of 6,429 pure Holstein (H) and Jersey (J) and ½ H x ½ J crossed cows calving from 1992 to 2010. The traits analyzed were test-day milk yields (MT), somatic cell score (SCS) and percentages of fat (%F) and protein (%P). Since the SCC is not normal distributed it was converted to a logarithmic scale in SCS, using the following equation, SCS = log2 (SCC/100) + 3. The variables MT, SCS, %F and %P were analyzed as dependent variables by least square method using GLM procedure. There were considered linear models containing the effects of breed (H, J and ½ H x ½ J or F1), herd, year and month of test as classificatory variables. Age at calving (AC) and days in milk (DM) were included as covariates (linear and quadratic effects) for all traits. The test-day milk yield was included as covariate for SCS model, %F and %P. All variables included
O artigo não apresenta resumo em português.