ABSTRACT We investigated the influence of poultry rearing factors, including strain, type of ventilation, and sex on the slaughter characteristics of broiler chickens. Factorial analysis of mixed data was employed to analyze the data from broiler flocks slaughtered between 2018 and 2020 in Mato Grosso do Sul, comprising 2,684 flocks and 82,486,500 birds. The characterization information considered included age at slaughter, average weight, date of slaughter, percentage of pododermatitis, percentage of scratches, percentage of pre-slaughter condemnations, percentage of slaughter condemnations, percentage of total condemnation, percentage of field mortality, type of ventilation, strain, and sex. The factorial analysis of mixed data aimed to identify the relationships between pre-slaughter factors and slaughter characteristics. Five main components, explaining 85.5% of the total data variance, were derived from the analysis. Age, generated value per kilo of product, and percentage of pre-slaughter condemnations exhibited positive correlations. Negative pressure ventilation was found to be more closely associated with the percentage of pododermatitis, while the dark house system showed a stronger association with the percentage of total condemnation and percentage of pre-slaughter condemnation. The Cobb strain and female sex were found to be more strongly related to the generated value of the product. Strain, sex, and type of ventilation were identified as decisive factors influencing the characteristics of meat yields and the economic results of poultry activity in slaughterhouses. Moreover, it was observed that percentages of scratches and pododermatitis were negatively correlated with the value generated ($/kg) by broiler flocks, and they were more closely associated with positive pressure ventilation systems, Ross strain, mixtures of strains within the same flock, and male chickens. It was possible to prove the strong interdependence between the rearing stage of broiler chickens and the slaughterhouse, which needs to be considered in decision making by agroindustry to achieve an ideal rearing model. 201 202 Sul 2684 2 684 2,68 82486500 82 486 500 82,486,50 birds weight preslaughter pre mortality components 855 85 5 85.5 variance Age product correlations Strain slaughterhouses Moreover $/kg kg ($/kg systems flock slaughterhouse model 20 268 68 2,6 8248650 8 48 50 82,486,5 85. 26 6 2, 824865 4 82,486, 82486 82,486 8248 82,48 824 82,4 82,

ABSTRACT The objective was to evaluate the inclusion of chitosan (CHI) and technical cashew nut shell liquid (CNSLt) as natural feed additives in cattle diets on nutrient digestibility, ruminal fermentation, and in vitro gas production kinetics. We conducted a completely randomized design with 5×4 factorial arrangement, with 20, 35, 50, 65, and 100% Tifton 85 hay and four additives, monensin (200 mg/kg DM), CNSLt (500 mg/kg DM), CHI (500 mg/kg DM), and CNSLt+CHI (500 mg/kg DM/each). Dry matter (DM) and organic matter (OM) digestibility showed a linear reduction according to forage levels. The highest DM digestibility was observed with CHI on cattle diets. Inclusion of CHI increased DM digestibility. The highest in vitro organic matter and crude protein (CP) digestibilities were observed for CNSLt+CHI. The in vitro dry matter digestibility increased linearly with concentrate in the diet. There was interaction of forage:concentrate ratio and the additives for neutral detergent fiber, acid detergent fiber and hemicellulose digestibility. Chitosan, CNSLt, and CNSLt+CHI promoted the lowest acetate:propionate ratio compared with monensin. Total gas production showed interaction of the forage:concentrate ratio and additives. Lag time was lowest with CNSLt+CHI. Chitosan and CNSLt can be considered alternative fermentation modulators to ionophores by improving nutrient digestibility and increasing ruminal propionate concentrations.

Abstract Recent molecular tools and technologies have marked the discovery of the origin and domestication processes of a wide variety of species, using either genomic or mitochondrial molecular markers to provide input for selection programs, as well as the management and conservation of animal breeds. This study aimed to analyze genes of mitochondrial DNA of the following sheep (Ovis aries) breeds: Pantaneira, Bergamácia, Dorper, White Dorper, Ile de France and Hampshire Down, to obtain their population genetic parameters and investigate the origin of these sheep populations reared in the State of Mato Grosso do Sul. The analysis of mitochondrial DNA allowed to infer their phylogenetic relationships and revealed significant differences among them when compared with each other and with sequences obtained from GenBank. Through the formation of haplotypes, it was noted that the Pantaneira breed served as the maternal basis for the formation of the other breeds reared in the region, and it was possible to suggest a European origin for the sheep populations studied.

ABSTRACT The objective of this work was to study the behavior of swine females in the grower phase using different observation intervals (continuous, 5, and 10 min). A total of 42 swine were used, 14 of them for each treatment, which were identified with a marker stick. These animals were observed using the focal sampling method for 5 h. The treatments were the observation intervals: continuous, every 5 min, and every 10 min. Among the behaviors analyzed during the experiment, the different observation intervals did not affect the estimated time spent in the activities. Time observation intervals of 10 min or less adequately describe the duration of the main behavioral parameters of female pigs in this setting.

RESUMO Objetivou-se avaliar o efeito da inclusão de glicerina bruta (GB) em substituição ao milho, na dieta de cordeiros Pantaneiros confinados, sobre as características da carcaça e qualidade da paleta e do pernil. Foram utilizados 24 cordeiros machos, não castrados, em delineamento inteiramente casualizado, com quatro tratamentos (0, 2,5, 5,0 e 7,5% de GB em base da MS). Não houve efeito da inclusão de GB sobre os não componentes de carcaça. Houve efeito quadrático para peso de carcaça quente, com menor valor para 2,5% de GB. A composição regional e tecidual da carcaça não foi alterada pela substituição do milho pela GB. A composição tecidual da paleta e pernil e as características instrumentais da paleta não foram afetadas pelos teores de GB. Houve efeito quadrático para a intensidade de amarelo do pernil, com maior valor para 5,0% de GB. O teor de extrato etéreo da paleta apresentou efeito linear decrescente. Pode-se recomendar a utilização de 7,5% de GB, na matéria seca, em substituição ao milho, sem alteração das características da carcaça e qualidade da carne.

SUMMARY The objective was to assess the effect of inclusion of crude glycerin (CG) replacing corn in the diet of feedlot Pantaneiro lambs on the non-carcass components, regional and tissue composition, and carcass traits. Were used 24 not castrated males, in a completely randomized design with four treatments (0, 2.5, 5.0 and 7.5% of CG on DM basis). There was no effect of GB inclusion on non-carcass components. There was a quadratic effect for hot carcass weight, with lower value to 2.5% of CG. Regional and tissue composition of the carcass was not affected by the substitution of corn by CG. The tissue composition of shoulder and leg and instrumental traits of the shoulder were not affected by CG. There was a quadratic effect for the yellowness of the leg, with high value for 5.0% of GB. The ether extract content of shoulder showed decreased linear effect. The use of 7.5% of CG, in dry matter, can be recommend to replace corn of feedlot diets, without changing carcass traits and meat quality.

ABSTRACT This study assessed the use of conformation and fatness scores of the EUROP sheep carcass grading system to predict weight and percentage of salable meat from Brazilian market lambs. Data were collected from in vivo, carcass, and retail production from 252 uncastrated lambs. Evaluated models included single regressions, two multivariate models, and one determined by the stepwise procedure. Conformation was moderately correlated with weight of salable meat. Fatness scores were correlated with rump perimeter, carcass width, and thoracic depth with coefficients of −0.33, −0.32, and −0.23, respectively. Body weight was the best single predictor for weight of salable meat and cold carcass yield for percentage of salable meat. All multivariate models for weight of salable meat prediction were significant. Stepwise regression with body weight, leg perimeter, thoracic depth, rump perimeter, and fatness scores predicted 98% of weight of salable meat variation. For percentage of salable meat prediction, stepwise regression with cold carcass yield, leg perimeter, and conformation score was significant. The EUROP conformation and fatness scores can be used in Brazil for the prediction of lamb meat production.

RESUMO Objetivou-se avaliar o efeito da inclusão de níveis de glicerina bruta na alimentação de cordeiros nas características biométricas e histológicas testiculares. Foram utilizados 24 cordeiros não castrados, confinados com 93,79 ± 5,73 dias de idade e peso corporal de 20,22±2,84kg. Os tratamentos testados foram: 0; 2,5; 5,0 e 7,5% de inclusão de glicerina bruta na matéria seca da dieta em substituição ao milho. Os animais foram abatidos usando a condição corporal como critério em escore de 2,5 a 3,5, em uma escala que varia de 1 a 5, sendo que as variáveis avaliadas foram o peso inicial, peso final, peso de carcaça quente, espessura de gordura de cobertura, condição corporal, e os parâmetros biométricos testiculares: perímetro escrotal, peso testicular no escroto, peso dos testículos direito e esquerdo, volume dos testículos direito e esquerdo, largura testicular, comprimento testicular, diâmetro de túbulo seminífero e altura de epitélio germinativo. Não houve influência significativa dos níveis de glicerina bruta sobre nenhuma das variáveis analisadas, também não houve correlação entre as características avaliadas com a condição corporal. Foram observadas correlações positivas entre o peso de carcaça quente e espessura de gordura de cobertura (r=0,57, p<0,05). Houve correlação positiva (r=0,55, p<0,05)) entre perímetro escrotal e peso corporal. O diâmetro do túbulo (r=0,47, p<0,05) e a altura do epitélio seminíferos (r=0,62, p<0,05) estiveram correlacionados com o volume testicular. A inclusão de níveis crescentes de glicerina bruta na alimentação de cordeiros Pantaneiros até 7,5% de inclusão não influencia nas características biométricas e histométricas testiculares dos animais.

SUMMARY Objective to evaluate the effect of the inclusion of levels of crude Glycerin in the feeding of lambs in the biometric characteristics and testicular histological. 24 lambs were neutered, not confined with 93.79 ± 5.73 days of age and body weight of 20.22 ± 2.84 kg. The treatments tested were: 0; 2.5; 5.0 and 7.5% of crude Glycerin injection in dry matter of diet in place of maize. The animals were slaughtered using the criteria in body condition score of 2.5 to 3.5 on a scale ranging from 1 to 5, and the variables evaluated were the initial weight, final weight, hot carcass weight, fat cover thickness, body condition, and the biometric parameters: testicular weight, scrotal perimeter in the scrotum, testicle weight left and right volume of right and left testicle, testicular testicular length width, seminiferous tubule diameter and height of germinal epithelium. There was no significant influence of crude Glycerin levels on any of the variables analyzed, also there was no correlation between the features assessed with body condition. Positive correlations were observed between hot carcass weight and fat thickness (r=0,57, p= p<0,05)). There was positive correlation (r=0,55, p= p<0,05)) between scrotal perimeter and body weight. The tubule diameter (r=0,47, p=p<0,05) and height of the seminiferous epithelium (r=0,62, p=p<0,05) were correlated with testicular volume. The inclusion of increasing levels of crude Glycerin in the feeding of lambs Pantaneiros, did not influence the biometric characteristics and testicular histométrics of animals.

Em virtude da grande demanda por proteína de origem animal, tem-se aumentado a produção de frangos de corte e consequentemente a geração de resíduos provenientes do abate de aves, sendo necessário o desenvolvimento de técnicas que permitam o aproveitamento e reciclagem desses materiais. Objetivou-se com a execução deste trabalho avaliar a eficiência da compostagem no tratamento e reciclagem do resíduo sólido de abatedouro avícola. Utilizou-se resíduo sólido de abatedouro avícola comercial composto por fragmentos de vísceras, tecido muscular, adiposo e ósseo, sangue coagulado e penas e, como fonte de carbono, a casca de arroz. Montou-se uma leira com 1,5m3 de volume inicial, na qual foram monitorados os parâmetros: temperatura, teores de sólidos totais (ST), voláteis (SV), N, P, K, carbono orgânico (C), matéria orgânica compostável (MOC), matéria orgânica resistente à compostagem (MORC), demanda química de oxigênio (DQO), massa e volume enleirados, número mais provável (NMP) de coliformes totais e termotolerantes, bem como suas reduções durante o processo. A temperatura máxima atingida no centro da leira foi de 53,3ºC (média semanal), já as reduções de massa de ST e SV e volume durante o processo de pré-compostagem foram de 36,1; 44,3 e 23,3%, respectivamente, e, durante o processo de compostagem, foram de 21,8; 23,8 e 4,4%. A baixa redução do volume das leiras pode estar associada à alta concentração de MORC (40,1%) que pode ser principalmente relacionada à qualidade da fonte de carbono. O processo promoveu satisfatórias reduções totais de ST, SV e volume, sendo, respectivamente, 50,1; 57,5 e 26,7%. No entanto, foram observadas reduções de 43% na quantidade de nitrogênio presente no composto final. Apesar das reduções de nitrogênio, a compostagem demonstrou ser um método eficiente no tratamento dos resíduos sólidos de abatedouro avícola.

The great demand for animal protein was responsible for the increase on the broilers production and hence, the generation of waste from the poultry slaughter was increased as well, which in turn, propelled the development of techniques that allow the reuse and recycling of these wastes. The objective of this study was to evaluate the efficiency of composting on the treatment and recycling of solid waste from poultry slaughterhouse. The solid waste was from a commercial poultry slaughterhouse and was composed of viscera, muscle, fat, bone, blood and feathers that was mixed with a source of carbon, rice husk. Initially, a windrow with a volume of 1.5m3 was built, and then some parameters were monitored: temperature, total solids (TS), volatile (VS), N, P, K, organic carbon (C), composting organic matter (COC), organic matter resistant to composting (MORC), chemical oxygen demand (COD), mass and volume of the windrow, most probable number (MPN) of total and fecal coliforms, as well as their reductions during the process. The maximum temperature reached in the center of the windrow was 53.3°C (weekly average) since reductions of weight of TS and VS and volume during the pre-composting were 36.1, 44.3 and 23.3%, respectively and during the composting process was 21.8, 23.8 and 4.4%. The low volume reduction can be associated with high concentrations of MORC (40.1%) which can be mainly related to the quality of the carbon source. The process produced satisfactory total reductions of TS, VS and volume that were respectively, 50.1, 57.5 and 26.7%. However reductions were observed in 43% of amount of nitrogen in the final compound. Despite reductions in nitrogen content, composting proved to be an effective method in the treatment of solid waste from poultry slaughterhouse.

Background The aim of the present study was to assess the genetic diversity of Pantaneiro sheep, using microsatellite markers, in order to assist maintenance and management plans, enhance mating systems and reduce the inbreeding rate. A total of 127 animals were genotyped at eight microsatellite loci. They belonged to populations from the Experimental Farm of the Universidade Federal da Grande Dourados (UFGD) (Dourados/MS/Brazil) and Embrapa Pantanal (Corumbá/MS/Brazil). Results The population of Pantaneiro sheep from the UFGD exhibited a high mean number of alleles (11.13) and allelic richness (10.66). The polymorphic information content was highly informative in the locus studied, resulting in a mean value of 0.71. Observed heterozygosity was lower than expected for all molecular markers assessed. The analysis of molecular variance showed a differentiation rate of 5.2% between populations. Conclusions The results of the statistical parameters indicated that populations of Pantaneiro sheep require special attention on herd management, and it's further necessary to implement breeder exchange programs in order to preserve the genetic variability of these populations. Furthermore, the maintenance of those populations in their typical habitats is rather required to allow different responses from the herds to the interactions between genotype and environment.

O objetivo do trabalho foi verificar a eficiência da co-digestão anaeróbia dos dejetos suínos com crescentes níveis de adição de óleo de descarte e lipase. Foram testadas quatro doses de óleos (8, 12, 16 e 20g kg-1 de substrato) e 3 doses de lipase (1, 2 e 3g kg-1 de substrato). Os parâmetros avaliados foram: redução de sólidos totais (ST), sólidos voláteis (SV) e número mais provável (NMP) de coliformes totais (CT) e termotolerantes (CTT), além do pH, demanda química de oxigênio (DQO), produção e potenciais de produção de biogás. Os resultados demonstraram que houve influência das adições de óleo e lipase sobre as reduções de ST SV e pH do efluente, seguindo um modelo de predição linear e decrescente. As reduções do NMP de CT e CTT foram mais elevadas nos tratamentos com maior adição de óleo e lipase. A produção de biogás apresentou uma correlação negativa com as adições de lipase, sendo que estas proporcionaram efeito linear decrescente sobre os potenciais de produção de biogás/kg de dejeto, ST e SV adicionado. As adições de óleo e lipase não proporcionam efeitos favoráveis sobre as produções de biogás.

The goal this paper was to verify the efficiency of the anaerobic co-digestion of manure with increasing levels of added oil disposal and lipase. Were tested four levels oil (8, 12, 16 and 20 g kg-1 substrate) and 3 doses of lipase (1, 2, 3g-1 kg of substrate). The parameters evaluated were: reduction of total solids (TS), volatile solids (VS) and most probable number (MPN) of total coliforms (TC) and thermophilic (TTC), in addition to pH, chemical oxygen demand (COD), production and potential biogas production. The results demonstrated the influence of additions of oil and lipase to the reductions in SV and ST effluent pH, following a model of linear prediction and descending. The reductions in MPN of TC and TTC were higher in treatments with more adding oil and lipase. Biogas production showed a negative correlation with the additions of lipase, and these yielded linear effect on the potential of biogas/kg of manure, ST and SV added. The additions of oil and lipase did not provide favorable effects on biogas production.

O sequenciamento de Sanger, ou identificação das bases moleculares do DNA por terminação da cadeia, é um dos métodos amplamente utilizados para estudos moleculares. O uso da região citocromo b do DNA mitocondrial como marcador molecular se justifica pela presença de regiões conservadas e variáveis que podem ser sequenciadas e utilizadas em análises filogenéticas em diferentes níveis taxonômicos. O objetivo deste trabalho foi avaliar a variação do DNA mitocondrial por meio de sequenciamento de Sanger. Para tanto, amostras de tecido sanguíneo de ovinos do grupamento genético Pantaneiro (n=14), Bergamácia (n=4), Dorper (n=5) e Ile de France (n=5) foram utilizadas para extração de DNA. Logo em seguida as amostras foram submetidas a procedimentos de amplificação, purificação e sequenciamento. As análises estatísticas foram realizadas nos programas BioEdit 7.3.1.0 e MEGA 5.10. A utilização de primers internos e externos possibilitou o sequenciamento de 86% da região do citocromo b, o que indicou menor perda de nucleotídeos que acontece na reação de sequenciamento com apenas um par de primers. Os cálculos de diversidade média da região sequenciada permitiram observar baixa variação genética na população, evidenciando a natureza conservada do DNA herdado maternalmente. O sequenciamento parcial da região do citocromo b foi capaz de mostrar a variação do DNA mitocondrial em ovinos de 4 raças diferentes e proporcionou gerar dados para a realização de estudos futuros de origem e evolução dos animais.

The objective of this study was to analyze the influence of genetic group (GG) of the calf during gestation, mobilization of body reserves and period of postpartum anestrus in Nellore cows. Thirty-seven primiparous and multiparous cows were used: 24 gave birth to Nellore (NEL), and 13 gave birth to ½ Simmental × ½ Nellore (SIM) calves. According to the date of calving, cows were divided into three blocks, with intervals of 20 days between blocks. The body condition (BC) of the cows was estimated subjectively on a scale from 0 to 5 points, with intermediate grading of 0.5 points. We measured the thickness of subcutaneous fat (SF) between the 12th and 13th ribs and rump by ultrasound. Blood samples from each cow were collected weekly from the third week after birth until weaning, to analyze the level of progesterone; in the samples collected until 16 weeks postpartum, we analyzed the concentration of nonesterified fatty acids (NEFA). The gestation period of mothers of NEL calves was eight days longer, on average. The variables relating to the mobilization of body reserves (NEFA, BC and SF) were not influenced by calf GG, with the only significant effects being the number of days postpartum, with a peak in the concentration of NEFA between the sixth and eighth weeks and linear decrease in BC and NF. Mothers of NEL calves remained in anestrus for 4.6 weeks longer than the mothers of crossbred calves.

O objetivo deste trabalho foi avaliar os efeitos de marinadas com soluções alcalinas sobre características da carne de porco submetida a quedas do pH post-mortem, em músculo de porco. O pH das carcaças foi medido em abatedouro comercial (n = 526), aos 45 min pós-abate (pH45) e, em seguida, as carcaças foram divididas em grupos com pH45<5,7 ou pH45>5,7. Dez amostras do músculo longissimus dorsi de cada grupo foram coletadas e distribuídas em delineamento inteiramente casualizado, em arranjo fatorial 2x4, com duas condições (pH45<5,7 ou pH45>5,7) e quatro soluções de marinação: TC, controle sem marinação; TM1, bicarbonato de sódio e cloreto de sódio; TM2, tripolifosfato de sódio e cloreto de sódio; TM3, bicarbonato de sódio, tripolifosfato de sódio e cloreto de sódio. Não houve interação entre o pH45 da carne e os tratamentos marinados. As carnes com pH45<5,7 apresentaram maior luminosidade, perda por purga (PP), perda de exsudato (PE), perda de peso por cozimento (PC) e força de cisalhamento (FC). A marinação aumentou o pH da carne, reduziu a luminosidade, PE, PC e FC, e melhorou a maciez, suculência e palatabilidade. As marinadas com soluções alcalinas de cloreto, bicarbonato e tripolifosfato de sódio são eficazes no melhoramento da qualidade da carne suína, o que torna as características físicas das carnes processadas com marinadas semelhantes às da carne in natura, em consequência da acelerada glicólise post-mortem.

The objective of this work was to evaluate the effects of alkaline solution marinades on the characteristics of pork subjected to post-mortem pH decrease in pig muscle. The pH of carcasses was measured in a commercial slaughterhouse (n = 526), 45 min after slaughtering (pH45) and, then, the carcasses were divided into the groups with pH45<5.7 or pH45>5.7. Ten samples of the longissimus dorsi muscles of each group were collected and distributed in an entirely randomized design, in a 2x4 factorial arrangement, with two conditions (pH45<5.7 or pH45>5.7), and four marinade solutions: TC, no marinade; TM1, sodium bicarbonate and sodium chloride; TM2, sodium tripolyphosphate and sodium chloride; TM3, sodium bicarbonate, sodium tripolyphosphate and sodium chloride. There was no interaction between pH45 of the meat and the marinade treatments. Meat with pH45<5.7 showed higher values for lightness, and for purge loss (PL), exudate loss (EL), cooking loss (CL) and shear force (SF). Marinating increased the pH, reduced the lightness, EL, CL and SF, and improved tenderness, juiciness and flavor of meat. Marinades with solutions containing chloride, bicarbonate, and sodium tripolyphosphate are effective in the improvement of pork quality, making physical characteristics of marinated meat similar to those of fresh pork, as a consequence of accelerated postmortem glycolysis.

The objective of the present study was to estimate genetic parameters for test-day milk, fat and protein yields and 305-day-yields in Murrah buffaloes. 4,757 complete lactations of Murrah buffaloes were analyzed. Co-variance components were estimated by the restricted maximum likelihood method. The models included additive direct genetic and permanent environmental effects as random effects, and the fixed effects of contemporary group, milking number and age of the cow at calving as linear and quadratic covariables. Contemporary groups were defined by herd-year-month of test for test-day yields and by herd-year-season of calving for 305-day yields. The heritability estimates obtained by two-trait analysis ranged from 0.15 to 0.24 for milk, 0.16 to 0.23 for protein and 0.13 to 0.22 for fat, yields. Genetic and phenotypic correlations were all positive. The observed population additive genetic variation indicated that selection might be an effective tool in changing population means in milk, fat and protein yields.

Este estudo foi realizado com o objetivo de calcular valores econômicos para as produções de leite (PL), gordura (PG) e proteína (PP) em um sistema de produção de bubalinos leiteiros do estado de São Paulo. Foi desenvolvido um modelo bioeconômico para cálculo do desempenho produtivo, das receitas e dos custos de um rebanho comercial com produção de leite a pasto, suplementação com volumoso na seca e com concentrado durante todo o ano, de acordo com a produção de leite. Os valores econômicos foram calculados pela diferença marginal no lucro anual da fazenda, resultante da mudança em uma unidade da característica, mantendo-se as demais constantes. Foram analisados dois sistemas com diferentes objetivos de seleção: leite - produção de leite para venda ao laticínio; mozarela - produção de leite para fabricação (na própria fazenda) e venda de mozarela. Foram realizadas análises de sensibilidade para avaliar o impacto da mudança nos preços do concentrado, do leite e da mozarela sobre os valores econômicos das características estudadas. Os valores econômicos (R$) para as produções de leite, gordura e proteína no sistema leite foram, respectivamente, 0,71; -0,74 e -0,82 e, para o sistema mozarela, 3,05; 18,66 e 54,38 e indicam que, na política de pagamento vigente, a seleção para a produção de gordura e proteína não é desejável em sistemas de produção cujo objetivo exclusivo é a produção e venda do leite. A agregação da produção de mozarela ao processo produtivo desses sistemas poderia ser economicamente interessante, desde que houvesse a disponibilidade de recursos financeiros.

This study was aimed at calculating the economic values for milk (MY), fat (FY) and protein (PY) yields for a dairy buffalo production system in São Paulo State. The performance, revenues and costs were estimated based on a bio-economic model developed for a herd of dairy buffaloes raised in a grazing system, with roughage supply during the dry season and concentrate throughout the year. Economic values were calculated from the marginal difference of annual profit resulting from the increase of one unity of the trait, keeping the others constant. Two different commercial systems were considered: 1) The milk production is sold to industry (MILK) and 2) The milk is used to produce mozzarella cheese on the farm (MOZZARELLA). Sensitivity analyses were carried out to evaluate the impact of changes in concentrate, milk and mozzarella prices on the economic values. The economic values of MY, FY and PY respectively in the MILK and in the MOZZARELLA system were R$ 0.71; R$ -0.74 and R$ -0.82 and R$ 3.05; R$ 18.66 and R$ 54.38. These results suggest that under the current payment policy it is not desirable to improve fat and protein yields when the revenues are based on selling the milk production. The production of mozzarella on the farm may be economically interesting to these systems but depends on availability of financial resources for that investment.