Genetic association between fat-to-protein ratio and traits of economic interest in early lactation Holstein cows in Brazil.

The aims of this study were to estimate the genetic parameters for fat-to-protein ratio (F:P) within the first 90 days of lactation and to examine their genetic associations with daily milk yield (MY), somatic cell score (SCS), and calving interval between the first and second calving (IFSC) and between the second and third calving (ISTC) during the first three lactations of Holstein cows. We utilized 200,626 production-related data officially recorded from 77,436 cows milked two or three times a day from 2012 to 2022, sourced from the Holstein Cattle Breeders Association of Paraná State, Brazil. The (co)variance components were estimated using animal models, adopting the restricted maximum likelihood (REML) method with single-trait analysis (for heritability and repeatability) and two-trait analysis (for genetic and phenotypic correlations), per lactation. Regardless of lactation number, heritability estimates were relatively low, ranging from 0.08 ± 0.005 to 0.10 ± 0.003 for F:P; 0.08 ± 0.01 to 0.18 ± 0.005 for MY; 0.04 ± 0.01 to 0.07 ± 0.004 for SCS; and 0.03 ± 0.01 for both IFSC and ISTC. Repeatability estimates within the same lactation were low for F:P (ranging from 0.17 ± 0.002 to 0.19 ± 0.03), high for MY (between 0.50 ± 0.003 and 0.53 ± 0.002), and moderate to high for SCS (between 0.39 ± 0.003 and 0.44 ± 0.004). Genetic correlations between F:P and MY ranged from -0.26 ± 0.03 to -0.15 ± 0.02; F:P and SCS, from -0.06 ± 0.03 to -0.03 ± 0.08; F:P and IFSC, 0.31 ± 0.01; F:P and ISTC, 0.20 ± 0.01; MY and IFSC, 0.24 ± 0.05; and MY and ISTC, 0.13 ± 0.08. The fat-to-protein ratio during early lactation showed low genetic variability, regardless of lactation number. Furthermore, it was genetically correlated with MY, IFSC, and ISTC, although there is an antagonistic and unfavorable correlation between traits that can limit genetic progress.

Implications of supplementing mid-lactation multiparous Holstein cows fed high by-product low-forage diets with rumen-protected methionine and lysine in a commercial dairy.

Supplementation of rumen-protected amino acids may improve dairy cow performance but few studies have evaluated the implications of supplementing low-forage diets. Our objective was to evaluate the effects of supplementing rumen-protected methionine (Met) and lysine (Lys) on milk production and composition as well as on mammary gland health of mid-lactating Holstein cows from a commercial dairy farm feeding a high by-product low-forage diet. A total of 314 multiparous cows were randomly assigned to control (CON; 107 g of dry distillers' grains) or rumen-protected Met and Lys (RPML; 107 g dry distillers' grains + 107 g of RPML). All study cows were grouped in a single dry-lot pen and fed the same total mixed ration diet twice a day for a total of 7 weeks. Treatments were top-dressed on the total mix ration immediately after morning delivery with 107 g of dry distillers' grains for 1 week (adaptation period) and then with CON and RPML treatments for 6 weeks. Blood samples were taken from a subset of 22 cows per treatment to determine plasma AA (d 0 and 14) and plasma urea nitrogen and minerals (d 0, 14, and 42). Milk yield and clinical mastitis cases were recorded daily, and milk components were determined bi-weekly. Body condition score change was evaluated from d 0 to 42 of the study. Milk yield and components were analyzed by multiple linear regression. Treatment effects were evaluated at the cow level considering parity and milk yield and composition taken at baseline as a covariate in the models. Clinical mastitis risk was assessed by Poisson regression. Plasma Met increased (26.9 vs 36.0 µmol/L), Lys tended to increase (102.5 vs 121.1 µmol/L), and Ca increased (2.39 vs 2.46 mmol/L) with RPML supplementation. Cows supplemented with RPML had higher milk yield (45.4 vs 46.0 kg/d) and a lower risk of clinical mastitis (risk ratio = 0.39; 95% CI = 0.17-0.90) compared to CON cows. Milk components yield and concentrations, somatic cell count, body condition score change, plasma urea nitrogen, and plasma minerals other than Ca were not affected by RPML supplementation. Results suggest that RPML supplementation increases milk yield and decreases the risk of clinical mastitis in mid-lactation cows fed a high by-product low-forage diet. Further studies are needed to clarify the biological mechanisms for mammary gland responses to RPML supplementation.

Milk fat to protein ratio in the first test-day after calving on dairy cows / Relação gordura: proteína do leite no primeiro controle leiteiro pós-parto em vacas leiteiras

ABSTRACT: This study evaluated milk fat to protein ratio (FPR) in the first test-day after calving of dairy cows in Paraná State. Data from 257,847 first monthly test-days after calving of 114,162 cows were submitted to analysis after the data edition. Procedures MIXED, CORR and STEPWISE from SAS were used in the data analysis. In order to validate FPR, a herd with regular postpartum monitoring of blood β-hydroxybutyrate (BHB) was used to estimate the correlation with FPR. There was a strong positive correlation between FPR and fat content (r = 0.85; P < 0.01) and a weak negative correlation between FPR and protein content (r = - 0.23; P < 0.01). The regression equation that best fitted FPR was 1.1806 + 0.3304*%F - 0.3877*%P (R2 = 0.98), where the variable with the greatest influence was milk fat content (partial R2 = 0.72). Animals of 4th and 5th or more lactations had higher (P < 0.01) FPR, followed by animals of third, first, and second lactations. Jersey cows had higher (P < 0.01) FPR than Holsteins and Brown Swiss animals. Cows milked twice daily had higher (P < 0.01) FPR than animals milked three times daily. There were small positive correlations between milk FPR and blood BHB on days 4, 7 and 12 after calving (0.07, 0.13, and 0.14, respectively). In conclusion, milk fat content was reported to be the most important variable affecting FPR changes, but the milk FPR has limited value to evaluate hyperketonemia incidence during the transition period.

RESUMO: Este estudo teve como objetivo avaliar a relação gordura:proteína (RGP) no primeiro controle leiteiro no pós-parto de vacas no estado do Paraná. Dados de 257.847 controles de 114.162 vacas leiteiras, realizados no primeiro controle mensal após o parto foram submetidos à análise estatística após edição dos dados. Os procedimentos MIXED, CORR e STEPWISE do programa estatístico SAS 9.4 foram utilizados. A fim de validar a RGP, um rebanho com monitoramento regular de β-hidroxibutirato (BHB) no sangue foi utilizado para estimar a correlação com RGP. Observou-se uma correlação forte e positiva entre a RGP e teor de gordura no leite (r = 0,85; P < 0,01) e uma correlação fraca e negativa entre a RGP e o teor de proteína (r = -0,23; P < 0,01). A equação de regressão que melhor se ajusta à RGP foi 1,1806 + 0,3304*%G - 0,3877*%P (R2 = 0,98), na qual a variável com maior influência foi a porcentagem de gordura (R2 = 0,72). Animais de 4ª e 5ª lactações ou mais, apresentaram maior (P < 0,01) RGP, seguidos dos animais de terceira, primeira e segunda lactações, com menores RGP. Vacas da raça Jersey apresentaram maior (P < 0,01) RGP que vacas da raça Holandesa e Pardo-Suíça. Animais com duas ordenhas diárias apresentaram maior (P < 0,01) RGP que os animais ordenhados três vezes ao dia. Observaram-se correlações positivas, mas de pequena magnitude, entre a RGP do leite e BHB no sangue no quarto, sétimo e 12 dias pós-parto (0,07, 0,13 e 0,14; respectivamente). Concluindo, o teor de gordura é o fator que mais impacta as variações da RGP do leite, mas a RGP tem valor limitado na avaliação da incidência de hipercetonemia no período de transição.

Milk fat to protein ratio in the first test-day after calving on dairy cows / Relação gordura: proteína do leite no primeiro controle leiteiro pós-parto em vacas leiteiras

This study evaluated milk fat to protein ratio (FPR) in the first test-day after calving of dairy cows in Paraná State. Data from 257,847 first monthly test-days after calving of 114,162 cows were submitted to analysis after the data edition. Procedures MIXED, CORR and STEPWISE from SAS were used in the data analysis. In order to validate FPR, a herd with regular postpartum monitoring of blood ß-hydroxybutyrate (BHB) was used to estimate the correlation with FPR. There was a strong positive correlation between FPR and fat content (r = 0.85; P < 0.01) and a weak negative correlation between FPR and protein content (r = - 0.23; P < 0.01). The regression equation that best fitted FPR was 1.1806 + 0.3304*%F - 0.3877*%P (R2 = 0.98), where the variable with the greatest influence was milk fat content (partial R2 = 0.72). Animals of 4th and 5th or more lactations had higher (P < 0.01) FPR, followed by animals of third, first, and second lactations. Jersey cows had higher (P < 0.01) FPR than Holsteins and Brown Swiss animals. Cows milked twice daily had higher (P < 0.01) FPR than animals milked three times daily. There were small positive correlations between milk FPR and blood BHB on days 4, 7 and 12 after calving (0.07, 0.13, and 0.14, respectively). In conclusion, milk fat content was reported to be the most important variable affecting FPR changes, but the milk FPR has limited value to evaluate hyperketonemia incidence during the transition period.

Este estudo teve como objetivo avaliar a relação gordura:proteína (RGP) no primeiro controle leiteiro no pós-parto de vacas no estado do Paraná. Dados de 257.847 controles de 114.162 vacas leiteiras, realizados no primeiro controle mensal após o parto foram submetidos à análise estatística após edição dos dados. Os procedimentos MIXED, CORR e STEPWISE do programa estatístico SAS 9.4 foram utilizados. A fim de validar a RGP, um rebanho com monitoramento regular de ß-hidroxibutirato (BHB) no sangue foi utilizado para estimar a correlação com RGP. Observou-se uma correlação forte e positiva entre a RGP e teor de gordura no leite (r = 0,85; P < 0,01) e uma correlação fraca e negativa entre a RGP e o teor de proteína (r = -0,23; P < 0,01). A equação de regressão que melhor se ajusta à RGP foi 1,1806 + 0,3304*%G - 0,3877*%P (R2 = 0,98), na qual a variável com maior influência foi a porcentagem de gordura (R2 = 0,72). Animais de 4ª e 5ª lactações ou mais, apresentaram maior (P < 0,01) RGP, seguidos dos animais de terceira, primeira e segunda lactações, com menores RGP. Vacas da raça Jersey apresentaram maior (P < 0,01) RGP que vacas da raça Holandesa e Pardo-Suíça. Animais com duas ordenhas diárias apresentaram maior (P < 0,01) RGP que os animais ordenhados três vezes ao dia. Observaram-se correlações positivas, mas de pequena magnitude, entre a RGP do leite e BHB no sangue no quarto, sétimo e 12 dias pós-parto (0,07, 0,13 e 0,14; respectivamente). Concluindo, o teor de gordura é o fator que mais impacta as variações da RGP do leite, mas a RGP tem valor limitado na avaliação da incidência de hipercetonemia no período de transição.

Block freeze concentration by centrifugation and vacuum increases the content of lactose-free milk macronutrients.

Lactose-free milk is rising in popularity among consumers due to its claim to be a better digestible product compared to regular fluid milk. For that reason, concentrating on this food is a good alternative for increasing its versatility and usability in different dairy industry segments. Block freeze concentration (BFC) is a simple technology used to concentrate liquid foods through ice crystal formation and subsequent removal of water. Thus, this work aimed to test two variants of the BFC technique on lactose-free milk concentration. In the first approach, it was investigated the centrifugation-assisted BFC of skim lactose-free milk by applying a factorial experimental design. Temperature, time, and rotation speed were the factors, and the response variables included the concentrate yield, concentration index, and efficiency of the process. Concentrate yield and concentration index were mainly affected by the centrifugation temperature. On the other hand, individual factors did not have a significant effect on the efficiency, only their interactions. In the case of centrifugation-assisted BFC in a single step, the condition at 40°C, 70 min, and 4500 rpm was considered the best, given the highest values of efficiency and concentrate yield (80.87 and 67.02, respectively), and still an excellent value for concentration index (2.05). Conversely, the condition at 30°C, 45 min, and 3500 rpm was chosen to integrate a freeze concentration process in two stage. Then, the ice obtained from the first cycle was subjected to the vacuum-assisted BFC, which consisted in the second cycle. The concentrate obtained from the vacuum-assisted BFC presented contents of total solids, carbohydrates, and protein 2.95, 3.00, and 2.91 times more than the initial lactose-free milk, respectively. Therefore, we believe that the concentrates obtained can be used for the development of innovative lactose-free dairy products. PRACTICAL APPLICATION: Using concentration processes in the dairy industry can significantly contribute to enhancing the overall efficiency of milk processing since huge quantities of water from milk can be reduced, increasing the total solids content. In turn, dairy products that provide a high amount of solids (especially protein) are gaining in popularity among consumers, with consequent interest from researchers. In addition, milk concentration shows advantages in terms of processing, packaging, transportation, and handling. Since most changes occur in an aqueous environment, the removal of some parts of water results in the preservation of milk. It is noteworthy that dairy industries are concerned principally with food preservation, green technologies, and the production of high-quality products. Thus, concentration processes could favor the development of milk products rich in proteins to meet certain demands on functional and nutritional properties, for example in beverages and formulated food.

Methionine Supplementation during Pregnancy of Goats Improves Kids' Birth Weight, Body Mass Index, and Postnatal Growth Pattern.

The last third of gestation is a period of high energy and protein demand for the dam to support fetal growth and the following onset of lactation. Methionine is an essential amino acid that contributes to protein formation, fetal development, and milk synthesis; thus, is likely to have positive effects on the weight and size of the newborn and, afterward, milk yield and milk composition, which may improve growth patterns of the progeny. To test these hypotheses, we used 60 pregnant multiparous Alpine goats with similar live weights and gestational ages (~Day 100 of pregnancy; Mean ± SD; 1410 ± 14 days old and 50.4 ± 6.6 kg) and were separated into two groups: control and supplemented with the delivery. Treatments were T-MET (n = 30; received 1% herbal methionine Optimethione® dry matter based on from Day 100 of the pregnancy to delivery) or T-CTL (n = 30; served as the control and did not receive methionine). The methionine powder provided individual supplementation and was adjusted every week as the live weight and dry matter intake changed. At birth, the weight, body mass index (BMI), birth type, and sex of the kids were determined. Subsequently, the progeny was weighed weekly up to weaning. Two weeks after parturition, the milk composition was recorded weekly, and the milk yield was recorded monthly. The maternal live weight at the start (Mean ± SEM; T-CTL: 50.5 ± 1.1 vs. T-MET: 50.3 ± 1.3 kg) and end (T-CTL: 54.2 ± 1.3 vs. T-MET: 52.8 ± 1.4 kg) of the experiment did not differ statistically among treatments (p > 0.05); however, daily live weight changes tended to differ between groups (T-CTL: 73 ± 10 vs. T-MET: 51 ± 7 g day−1; p = 0.06). The birth weight (T-CTL: 3.1 ± 0.1 vs. T-MET: 3.5 ± 0.1 kg; p < 0.001), daily live weight change (T-CTL: 121 ± 6 vs. T-MET: 141 ± 6 g day−1; p < 0.01), and weaning weight (T-CTL: 8.3 ± 0.2 vs. T-MET: 9.3 ± 0.3 kg; p < 0.01) differed between treatments. The BMI at birth (T-CTL: 0.28 ± 0.01 vs. T-MET: 0.3 ± 0.01 units kg m−2; p < 0.01) and at weaning (T-CTL: 0.85 ± 0.1 kg vs. T-MET: 1.00 ± 0.06 units kg m−2; p < 0.05) differed between treatments. Milk components (protein, fat, lactose, and solids non-fat) and milk yield were similar between treatments (p > 0.05). It is concluded that the inclusion of methionine in the maternal goat diet during the last third of gestation increases the birth and growth variables of the progeny but without significant influence on the milk yield and composition.

Milk yield and composition and body weight of offsprings of mixed-breed goats on semi-arid rangelands with different rainfall.

The objective was to characterize milk yield and composition from mixed-breed goats kidding in winter and grazing rangelands with 221 (n = 15), 334 (n = 20), or 441 (n = 12) mm of annual rainfall in northern Mexico (22-25°N). Weekly milk yield and composition were recorded and progeny growth performance assessed. Body weight loss during lactation was the highest (6.4 kg) for goats on rangeland with 441 mm of rainfall than goats on 221 mm (1.6 kg), or 334 mm (1.8 kg; P < 0.01). The highest daily milk yield was for goats on 221 mm (498 mL; P < 0.01). There was not an evident peak of lactation and milk yield increased uninterruptedly at the end of lactation. Milk fat was negatively related to milk yield and goats on rangeland with 334 mm had the greatest milk fat content (P < 0.001). Milk protein and lactose content were higher in goats on rangeland with 221 mm (P < 0.01). Goat kids on rangelands with 221 and 441 mm grew faster and were heavier (P < 0.001) at weaning than kids reared in other rangelands. Weaning weight was positively related to milk yield (P < 0.001); but not milk components (P > 0.05). In conclusion, moderate milk yield of mixed-breed goats on rangeland is feasible with parturitions in winter, and milk yield is not affected by reduced annual precipitation in rangelands of northern Mexico. Offspring growth performance depends on maternal milk yield, but not milk composition. Nevertheless, slow growth to weaning of offspring had adverse effects on time to reach adequate market weight.

Ocitocina na produção e composição do leite / Oxytocin application in production and milk composition

Objetivou-se analisar a aplicação da ocitocina influenciando na eficiência da ejeção do leite; ao ponto de ocorrer um aumento da produção e mudanças na composição. Foram utilizados 45 animais, durante 105 dias, divididos em três tratamentos, no tratamento 1 (T1) os animais receberam 0,5ml de soro fisiológico, logo após realizava-se a ordenha destes animais, sendo considerado o tratamento controle, no T2 os animais receberam ocitocina antes do início da ordenha, e logo após ordenhava-se estes animais; no T3 os animais receberam ocitocina ao final da ordenha e reordenhava-se estes animais. Para aferir a produção das vacas foram usados medidores de leite, com pesagens de produção realizadas quinzenalmente. Após aferido a produção de todos os animais, as amostras de leite foram coletadas e encaminhadas para as análises posteriores. As variáveis físico-químicas do leite analisadas foram: porcentagem de gordura, lactose e proteína. Os resultados foram submetidos à análise de variância e posteriormente, ao teste de comparação de médias, com diferença estatística significativa de 5%. De acordo com os resultados obtidos a ocitocina influenciou na produção leiteira com um aumento na produtividade diária por animal, mas não se observou diferenças significativas nas médias de porcentagem de gordura, lactose e proteína do leite.(AU)

This study aimed to analyze the application of oxytocin influence in the milk ejection efficiency; as to occur an increase in production and changes in milk composition. 45 animals were used for 105 days, divided into three treatments, the treatment one received 0.5ml of physiological saline, in the treatment two were given oxytocin to the animals before the milking; and in treatment there the animals received oxytocin at the end of milking. To measure the cows milk production, milk meters were used, and were performed fortnightly. After measured the production of all animals, samples were collected and sent for analysis. The physicochemical variables analyzed were: percentage of fat, lactose and protein. The results were submitted to ANOVA and subsequently the mean comparison test, with statistical significance of 5%. According to obtained results oxytocin influence the milk production with a significant increase in daily productivity per animal, but there was no significant difference in percentage of fat, lactose and milk protein.(AU)

Ocitocina na produção e composição do leite / Oxytocin application in production and milk composition

Objetivou-se analisar a aplicação da ocitocina influenciando na eficiência da ejeção do leite; ao ponto de ocorrer um aumento da produção e mudanças na composição. Foram utilizados 45 animais, durante 105 dias, divididos em três tratamentos, no tratamento 1 (T1) os animais receberam 0,5ml de soro fisiológico, logo após realizava-se a ordenha destes animais, sendo considerado o tratamento controle, no T2 os animais receberam ocitocina antes do início da ordenha, e logo após ordenhava-se estes animais; no T3 os animais receberam ocitocina ao final da ordenha e reordenhava-se estes animais. Para aferir a produção das vacas foram usados medidores de leite, com pesagens de produção realizadas quinzenalmente. Após aferido a produção de todos os animais, as amostras de leite foram coletadas e encaminhadas para as análises posterior. As variáveis físico-químicas do leite analisadas foram: porcentagem de gordura, lactose e proteína. Os resultados foram submetidos à análise de variância e posteriormente, ao teste de comparação de médias, com diferença estatística significativa de 5%. De acordo com os resultados obtidos a ocitocina influenciou na produção leiteira com um aumento na produtividade diária por animal, mas não se observou diferenças significativas nas médias de porcentagem de gordura, lactose e proteína do leite.

This study aimed to analyze the application of oxytocin influence in the milk ejection efficiency; as to occur an increase in production and changes in milk composition. 45 animals were used for 105 days, divided into three treatments, the treatment one received 0.5ml of physiological saline, in the treatment two were given oxytocin to the animals before the milking; and in treatment theree the animals received oxytocin at the end of milking. To measure the cow's milk production, milk meters were used, and were performed fortnightly. After measured the production of all animals, samples were collected and sent for analysis. The physico-chemical variables analyzed were: percentage of fat, lactose and protein. The results were submitted to ANOVA and subsequently the mean comparison test, with statistical significance of 5%. According to obtained results oxytocin influence the milk production with a significant increase in daily productivity per animal, but there was no significant difference in percentage of fat, lactose and milk protein.

Ocitocina na produção e composição do leite / Oxytocin application in production and milk composition

Objetivou-se analisar a aplicação da ocitocina influenciando na eficiência da ejeção do leite; ao ponto de ocorrer um aumento da produção e mudanças na composição. Foram utilizados 45 animais, durante 105 dias, divididos em três tratamentos, no tratamento 1 (T1) os animais receberam 0,5ml de soro fisiológico, logo após realizava-se a ordenha destes animais, sendo considerado o tratamento controle, no T2 os animais receberam ocitocina antes do início da ordenha, e logo após ordenhava-se estes animais; no T3 os animais receberam ocitocina ao final da ordenha e reordenhava-se estes animais. Para aferir a produção das vacas foram usados medidores de leite, com pesagens de produção realizadas quinzenalmente. Após aferido a produção de todos os animais, as amostras de leite foram coletadas e encaminhadas para as análises posteriores. As variáveis físico-químicas do leite analisadas foram: porcentagem de gordura, lactose e proteína. Os resultados foram submetidos à análise de variância e posteriormente, ao teste de comparação de médias, com diferença estatística significativa de 5%. De acordo com os resultados obtidos a ocitocina influenciou na produção leiteira com um aumento na produtividade diária por animal, mas não se observou diferenças significativas nas médias de porcentagem de gordura, lactose e proteína do leite.

This study aimed to analyze the application of oxytocin influence in the milk ejection efficiency; as to occur an increase in production and changes in milk composition. 45 animals were used for 105 days, divided into three treatments, the treatment one received 0.5ml of physiological saline, in the treatment two were given oxytocin to the animals before the milking; and in treatment there the animals received oxytocin at the end of milking. To measure the cow’s milk production, milk meters were used, and were performed fortnightly. After measured the production of all animals, samples were collected and sent for analysis. The physicochemical variables analyzed were: percentage of fat, lactose and protein. The results were submitted to ANOVA and subsequently the mean comparison test, with statistical significance of 5%. According to obtained results oxytocin influence the milk production with a significant increase in daily productivity per animal, but there was no significant difference in percentage of fat, lactose and milk protein.

How can dairies maximize their profits and properly remunerate their dairy farmers?

The current pricing process of raw milk in Brazil discourages producers from improving milk composition, which affects both yield and quality of dairy products. Furthermore, small and medium-sized dairies face great difficulties when it comes to planning production. Thus, a linear programming model was developed to price the raw milk and determine the optimal mix (combination of quantities) of dairy products that maximizes total contribution margin (TCM) under daily scenarios of high (January) and low (July) raw milk supplies (summer and winter, respectively) by comparing optimal solutions with actual results. The TCM of optimal and actual mixes were higher in January due to the greater availability of raw material. Packaging was a limiting factor in the production of cheese in optimal mixes. The relationship between unit contribution margin (UCM) and the required amount of raw materials per product unit and resource availability is crucial to defining the mix of dairy products and TCM of the dairy. Casein and raw milk volume showed shadow prices. Under both scenarios, the calculated prices of raw milk were higher than the prices charged by the dairy and were higher in January. The proposed model remunerates the producers based on the quantity and quality of raw milk. The dairy can maximize its TCM by better planning its mix of products with the use of linear programming.(AU)

How can dairies maximize their profits and properly remunerate their dairy farmers?

The current pricing process of raw milk in Brazil discourages producers from improving milk composition, which affects both yield and quality of dairy products. Furthermore, small and medium-sized dairies face great difficulties when it comes to planning production. Thus, a linear programming model was developed to price the raw milk and determine the optimal mix (combination of quantities) of dairy products that maximizes total contribution margin (TCM) under daily scenarios of high (January) and low (July) raw milk supplies (summer and winter, respectively) by comparing optimal solutions with actual results. The TCM of optimal and actual mixes were higher in January due to the greater availability of raw material. Packaging was a limiting factor in the production of cheese in optimal mixes. The relationship between unit contribution margin (UCM) and the required amount of raw materials per product unit and resource availability is crucial to defining the mix of dairy products and TCM of the dairy. Casein and raw milk volume showed shadow prices. Under both scenarios, the calculated prices of raw milk were higher than the prices charged by the dairy and were higher in January. The proposed model remunerates the producers based on the quantity and quality of raw milk. The dairy can maximize its TCM by better planning its mix of products with the use of linear programming.

Milk traits of lactating cows submitted to feed restriction.

Data from five experiments with dairy cows where feed was restricted to 0, 40, and 50% of the ad libitum amount, with 259 observations, were subjected to multivariate analyses to determine the effects of severity and duration of feed restriction on production, physical-chemical characteristics, ethanol stability, and somatic cell score of milk. A negative relationship was seen between the severity and duration of feed restriction with milk production, lactose content, titratable acidity, and milk stability to the ethanol test. The milk stability to the ethanol test, protein content, milk yield, and somatic cells score were the most important attributes retained by the discriminant analysis. Milk stability to the ethanol test, live weight, days in restriction, and pH were the most important characteristics explaining the variance within the different levels of feed restriction. Milk production and ethanol stability were significantly lower in both levels of feed restriction compared with the group fed ad libitum. When feed restriction was followed by refeeding, the difference observed in ethanol stability was the first discriminant variable, followed by the difference in unstable milk frequency and titratable acidity. Increments in the severity and duration of feed restriction negatively affect milk production and milk ethanol stability.

Body condition score (BCS) and calving order on milk production and composition in zebu cattle / Escore de condição corporal (ECC) e ordem de parto sobre a produção e composição de leite de vacas zebuínas

The present study aimed to evaluate the effect of body condition score (BCS) and calving order on milk production and composition in zebu cattle participating in an official dairy cow tournament. We analyzed milk samples from 47 Gyr, Guzerat and Red Sindhi cows, distributed into classes with respect to lactation stage, milk production, and body condition score. Means for milk composition were within standard ranges for zebu cattle, with the greatest variation recorded for fat and protein content. Fat content was higher for animals in the first month of lactation, with a mean of 5.69%, and protein content was highest after 60 days with an average of 3.55%. A positive correlation of 0.38% (p < 0.05) was observed between milk fat and protein content. First calving animals exhibited lower mean of milk production than those in their second calving or more. Animals with a BCS in class II demonstrated higher daily production up to 30 days of lactation. Body condition score influenced the milk production of zebu cows participating in a dairy cow competition up to the 30th day of lactation.(AU)

Objetivou-se avaliar o efeito do escore de condição corporal (ECC) e da ordem de parto (OP) sobre a produção e composição do leite de vacas de raças zebuínas participantes do torneio leiteiro oficial. Foram analisadas amostras de leite proveniente de 47 fêmeas das raças Gir, Guzerá e Sindi, distribuídas em classes quanto ao período de lactação, produção de leite e escore de condição corporal. As médias de composição do leite se encontram dentro dos padrões das raças zebuínas, sendo a maior variação observada para os teores de gordura e proteína. O teor de gordura foi maior para os animais no primeiro mês de lactação, com média de 5,69% e o de proteína após os 60 dias, com média de 3,55%. Houve correlação positiva entre o teor de gordura e proteína no leite que foi de 0,38% (P < 0,05). Os animais de primeira ordem de parto apresentaram média de produção de leite inferior aos de segunda ou mais. Os animais com ECC da classe II apresentaram superioridade para produção diária até os 30 dias de lactação. O escore de condição corporal influenciou a produção de leite de vacas zebu participantes do torneio leiteiro até os 30 dias de lactação.(AU)

Body condition score (BCS) and calving order on milk production and composition in zebu cattle / Escore de condição corporal (ECC) e ordem de parto sobre a produção e composição de leite de vacas zebuínas

The present study aimed to evaluate the effect of body condition score (BCS) and calving order on milk production and composition in zebu cattle participating in an official dairy cow tournament. We analyzed milk samples from 47 Gyr, Guzerat and Red Sindhi cows, distributed into classes with respect to lactation stage, milk production, and body condition score. Means for milk composition were within standard ranges for zebu cattle, with the greatest variation recorded for fat and protein content. Fat content was higher for animals in the first month of lactation, with a mean of 5.69%, and protein content was highest after 60 days with an average of 3.55%. A positive correlation of 0.38% (p < 0.05) was observed between milk fat and protein content. First calving animals exhibited lower mean of milk production than those in their second calving or more. Animals with a BCS in class II demonstrated higher daily production up to 30 days of lactation. Body condition score influenced the milk production of zebu cows participating in a dairy cow competition up to the 30th day of lactation.

Objetivou-se avaliar o efeito do escore de condição corporal (ECC) e da ordem de parto (OP) sobre a produção e composição do leite de vacas de raças zebuínas participantes do torneio leiteiro oficial. Foram analisadas amostras de leite proveniente de 47 fêmeas das raças Gir, Guzerá e Sindi, distribuídas em classes quanto ao período de lactação, produção de leite e escore de condição corporal. As médias de composição do leite se encontram dentro dos padrões das raças zebuínas, sendo a maior variação observada para os teores de gordura e proteína. O teor de gordura foi maior para os animais no primeiro mês de lactação, com média de 5,69% e o de proteína após os 60 dias, com média de 3,55%. Houve correlação positiva entre o teor de gordura e proteína no leite que foi de 0,38% (P < 0,05). Os animais de primeira ordem de parto apresentaram média de produção de leite inferior aos de segunda ou mais. Os animais com ECC da classe II apresentaram superioridade para produção diária até os 30 dias de lactação. O escore de condição corporal influenciou a produção de leite de vacas zebu participantes do torneio leiteiro até os 30 dias de lactação.

Fatores ambientais e de manejo sobre a composição química do leite em granjas leiteiras do Estado do Paraná, Brasil / Environmental and handling factors on the chemical composition of milk in dairy farms of Paraná State, Brazil

O objetivo do trabalho foi avaliar a influência da composição químicobromatológica da dieta total e os fatores ambientais das estações do ano sobre a composição química do leite. As granjas leiteiras estudadas foram identificadas como Granja 1 (G1) eGranja 2 (G2). Definiram-se como tratamento as quatro estações do ano e os dois sistemas de produção leiteira (G1 e G2). Foram coletadas 34 amostras da dieta total fornecida aosanimais em lactação para a análise da composição químico-bromatológica, e 20 amostras de leite cru diretamente dos tetos dos animais para avaliar a composição química do leite, durante as quatro estações ano. Para as análises estatísticas dos dados, foi empregado ométodo dos quadrados mínimos. Constatou-se que houve diferença (p < 0,05) entre a G1 e a G2 para a produção de leite (kg dia-1), porcentagens de gordura, proteína e níveis de ureia no leite (NUL). No entanto, não houve diferença na porcentagem de lactose e sólidos totaisentre as granjas estudadas. Observou-se que a produção (kg dia-1) e todos os componentes do leite analisados diferiram ao longo das quatro estações do ano. Os resultadosdemonstraram que a composição químico-bromatológica da dieta, as fases de lactação e os fatores ambientais das estações do ano podem causar variações na produção e composição química do leite.

The objective of this research study was to evaluate the influence of total diet chemical composition and environment factors of the different seasons of the year on the chemical composition of milk. The milk farms evaluated were classified as Farm 1 (G1) and Farm 2 (G2). The study defined as treatmentsthe four seasons of the year and the milk production system (G1 and G2). A total of 34 diet samples were collected, fed to lactating animals in order to analyze the chemicalbromatologicalcomposition, and 20 samples of raw milk straight from cows in order toevaluate the chemical composition of milk during the four seasons. For data statistical analyses, the method of least squares was used. There was a difference (p 0.05) in lactose and totalsolids percentage between the studied farms. On the other hand, it was observed that the production (kg day-1) and all analyzed milk components were different (p < 0.05) during the four seasons of the year. The results demonstrate that the total diet chemicalcomposition, lactation phases and environments factors of seasons of the year may cause variation in milk production and chemical composition.

Fatores ambientais e de manejo sobre a composição química do leite em granjas leiteiras do Estado do Paraná, Brasil / Environmental and handling factors on the chemical composition of milk in dairy farms of Paraná State, Brazil

O objetivo do trabalho foi avaliar a influência da composição químicobromatológica da dieta total e os fatores ambientais das estações do ano sobre a composição química do leite. As granjas leiteiras estudadas foram identificadas como Granja 1 (G1) eGranja 2 (G2). Definiram-se como tratamento as quatro estações do ano e os dois sistemas de produção leiteira (G1 e G2). Foram coletadas 34 amostras da dieta total fornecida aosanimais em lactação para a análise da composição químico-bromatológica, e 20 amostras de leite cru diretamente dos tetos dos animais para avaliar a composição química do leite, durante as quatro estações ano. Para as análises estatísticas dos dados, foi empregado ométodo dos quadrados mínimos. Constatou-se que houve diferença (p < 0,05) entre a G1 e a G2 para a produção de leite (kg dia-1), porcentagens de gordura, proteína e níveis de ureia no leite (NUL). No entanto, não houve diferença na porcentagem de lactose e sólidos totaisentre as granjas estudadas. Observou-se que a produção (kg dia-1) e todos os componentes do leite analisados diferiram ao longo das quatro estações do ano. Os resultadosdemonstraram que a composição químico-bromatológica da dieta, as fases de lactação e os fatores ambientais das estações do ano podem causar variações na produção e composição química do leite.(AU)

The objective of this research study was to evaluate the influence of total diet chemical composition and environment factors of the different seasons of the year on the chemical composition of milk. The milk farms evaluated were classified as Farm 1 (G1) and Farm 2 (G2). The study defined as treatmentsthe four seasons of the year and the milk production system (G1 and G2). A total of 34 diet samples were collected, fed to lactating animals in order to analyze the chemicalbromatologicalcomposition, and 20 samples of raw milk straight from cows in order toevaluate the chemical composition of milk during the four seasons. For data statistical analyses, the method of least squares was used. There was a difference (p < 0.05) betweenthe G1 and G2 farms, for milk production (kg day-1), fat, protein and milk urea nitrogen (MUN) percentages. However, no difference was observed (p > 0.05) in lactose and totalsolids percentage between the studied farms. On the other hand, it was observed that the production (kg day-1) and all analyzed milk components were different (p < 0.05) during the four seasons of the year. The results demonstrate that the total diet chemicalcomposition, lactation phases and environments factors of seasons of the year may cause variation in milk production and chemical composition.(AU)

Fatores de risco associados a falhas de concepção ao primeiro serviço em vacas leiteiras de alta produção / Risk factors associated with failure of first breeding pregnancy in dairy cows

Este estudo investigou os fatores de riscos para falhas na concepção ao primeiro serviço pós-parto (CPS). Vacas Holandesas (n = 427) tiveram seu desempenho reprodutivo, sanitário e nutricional acompanhados do período pré-parto até a CPS, sendo registrados as ocorrências de doenças e os escores de condição corporal (ECC), no pré e pós-parto, e as composições do leite. Análises de regressão logística foram utilizadas para se modelar os fatores de risco e na associação entre os diversos riscos para sucesso ou falha na CPS. As variáveis ordenadas foram: número da lactação, época do ano ao primeiro serviço, ocorrência de doenças no periparto (DP), relação entre as porcentagens de gordura e proteína do leite (RGP) e alterações no ECC. Animais primíparos apresentaram maior chance de sucesso ao primeiro serviço do que os multíparos. Vacas cobertas no inverno apresentaram, aproximadamente, cinco vezes mais chances de CPS do que as cobertas no verão. Animais com DP tiveram menor sucesso de concepção que os animais sadios. Vacas com melhor condição ruminal, determinada pela RGP, tiveram melhor concepção do que vacas com RGP reduzida. O ECC, adequado nas diferentes fases produtivas, demonstrou ser importante ferramenta para se identificar vacas com risco de insucesso na CPS.

This study investigated the risk factors for failure in the conception to the first postparturition service (CFS). Holstein cows (n = 427) had their reproductive, health and nutritional status monitored from the period of pre-parturition to the CFS. Occurrence of diseases and body condition scores (BCS), at pre- and post-parturition, as well as milk composition, were recorded. Logistic regression models were used to isolate the risk factors and associations among the several risks for success or failure in CFS. The variables studied were lactation number, season of the first service, occurrence of peripartum diseases (PD), ratio of fat and protein of milk (RFP) and alterations in BCS. Primiparous cows presented larger success chance for first service than multiparous specimens. The inseminated cows in the winter presented, approximately, five times more chances of CFS than the cows inseminated in the summer. Cows that presented PD had smaller conception success than healthy cows. The animals that presented a better ruminal condition, determined by RFP, had better conception than the animals with reduced RFP. BCS, appropriate in the different productive phases, proved to be an important tool to identify cows with failure risk in the CFS.

Fatores de risco associados a falhas de concepção ao primeiro serviço em vacas leiteiras de alta produção / Risk factors associated with failure of first breeding pregnancy in dairy cows

Este estudo investigou os fatores de riscos para falhas na concepção ao primeiro serviço pós-parto (CPS). Vacas Holandesas (n = 427) tiveram seu desempenho reprodutivo, sanitário e nutricional acompanhados do período pré-parto até a CPS, sendo registrados as ocorrências de doenças e os escores de condição corporal (ECC), no pré e pós-parto, e as composições do leite. Análises de regressão logística foram utilizadas para se modelar os fatores de risco e na associação entre os diversos riscos para sucesso ou falha na CPS. As variáveis ordenadas foram: número da lactação, época do ano ao primeiro serviço, ocorrência de doenças no periparto (DP), relação entre as porcentagens de gordura e proteína do leite (RGP) e alterações no ECC. Animais primíparos apresentaram maior chance de sucesso ao primeiro serviço do que os multíparos. Vacas cobertas no inverno apresentaram, aproximadamente, cinco vezes mais chances de CPS do que as cobertas no verão. Animais com DP tiveram menor sucesso de concepção que os animais sadios. Vacas com melhor condição ruminal, determinada pela RGP, tiveram melhor concepção do que vacas com RGP reduzida. O ECC, adequado nas diferentes fases produtivas, demonstrou ser importante ferramenta para se identificar vacas com risco de insucesso na CPS.(AU)

This study investigated the risk factors for failure in the conception to the first postparturition service (CFS). Holstein cows (n = 427) had their reproductive, health and nutritional status monitored from the period of pre-parturition to the CFS. Occurrence of diseases and body condition scores (BCS), at pre- and post-parturition, as well as milk composition, were recorded. Logistic regression models were used to isolate the risk factors and associations among the several risks for success or failure in CFS. The variables studied were lactation number, season of the first service, occurrence of peripartum diseases (PD), ratio of fat and protein of milk (RFP) and alterations in BCS. Primiparous cows presented larger success chance for first service than multiparous specimens. The inseminated cows in the winter presented, approximately, five times more chances of CFS than the cows inseminated in the summer. Cows that presented PD had smaller conception success than healthy cows. The animals that presented a better ruminal condition, determined by RFP, had better conception than the animals with reduced RFP. BCS, appropriate in the different productive phases, proved to be an important tool to identify cows with failure risk in the CFS.(AU)

Produção e composição química do leite em diferentes genótipos ovinos

The objective of this study was to evaluate production and chemical components of milk from Corriedale sheep and Corriedale x Milchschaf breed. Thirty-three Corriedale, 43 Corriedale x Milchschaf (F1), and 23 F1 (Corriedale x Milchschaf) x Milchschaf (F2) were used. Animals were milked twice daily, from September to December 2002. A total of five milking evaluation periods with a 21-day interval was conducted. Fat, protein and lactose contents were determined. A completely randomized design was used to evaluate the effect of genotype in milk production, corrected for 100 days and yield of fat, protein and lactose. In the mathematical model, age, number of sheep born and body condition were used as co-factors. Significant difference (P 0.0001) was found between genotypes in terms of milk production (kg), fat, protein, and lactose (g) corrected for 100 days of lactation. Genotypes F1 and F2 were the most productive.

O objetivo deste trabalho foi a avaliação da produção do leite e de seus componentes químicos de animais Corriedale e cruzas de Corriedale x Milchschaf. Foram utilizadas 33 ovelhas Corriedale, 43 cruzas Corriedale x Milchschaf (F1) e 23 cruzas F1 (Corriedale x Milchschaf) x Milchschaf (F2). Os animais foram ordenhados duas vezes ao dia, de setembro a dezembro de 2002. No total, foram realizados cinco controles leiteiros com intervalo de vinte e um dias. As amostras para composição química foram analisadas para determinação de gordura, proteína e lactose. Foi utilizado o delineamento completamente casualizado para avaliação do efeito do genótipo sobre a produção de leite corrigida para os 100 dias, e sobre a produção de gordura, proteína e lactose. No modelo matemático, a idade, o número de cordeiros ao parto e a condição corporal foram utilizadas como covariáveis. Houve diferença significativa (P 0,0001) entre os genótipos para a produção de leite (kg), gordura, proteína e lactose (g) corrigidas aos 100 dias de lactação, de modo que o genótipo F1 e F2 mostraram-se mais produtivos.