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

ABSTRACT 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

Evaluation of methods of dna extraction from staphylococcus aureus in milk for use in real-time pcr

The aim of this study was to evaluate the repeatability and performance of 4 methods of extracting DNA from Staphylococcus aureus (SAU) and the gene encoding bovine mitochondrial cytochrome B (BMCB) in milk samples from cows with subclinical mastitis for use in amplification by real-time polymerase chain reaction. Two milk samples were obtained from cows naturally infected with S. aureus and subjected to the following extraction methods: Qiagen DNA extraction kit; Axyprep DNA extraction kit; in silica column boil and in silica column method. After extraction in duplicate, eluates were subjected to purification and precipitation to determine purity (A260/A280 ratio) and concentration (μg/μL) by spectrophotometry and amplification by real-time polymerase chain reaction of target genes (SAU and BMCB). There was no effect of the DNA extraction method on DNA concentration and threshold cycle for BMCB and SAU. The purity ratio (A260/A280) was higher when using Qiagen DNA extraction (1.76 ± 0.136) compared to the other methods tested. Our results indicate that the DNA extraction kit from Qiagen produces samples of the highest purity ratio compared to other methods

Detection and enumeration of Staphylococcus aureus from bovine milk samples by real-time polymerase chain reaction

The aim of this study was to develop and evaluate a real-time quantitative PCR (qPCR)-based method to detect and quantify Staphylococcus aureus in bronopol-preserved milk samples from subclinical intramammary infections (IMI). Serial dilutions of milk artificially inoculated with Staph. aureus ATCC 29213 were used to establish a standard curve (cfu/mL) of the qPCR assay targeting the Staph. aureus thermonuclease-encoding gene nuc according to the strain plate count. The analytical sensitivity, specificity, and repeatability of the qPCR assay were determined. A total of 60 milk samples, collected from mammary quarters without abnormal appearance and with positive isolation of Staph. aureus, were submitted to both the qPCR protocol and Staph. aureus plate counting and results from both methods were compared. Staphylococcus aureus from bronopol-preserved, subclinical IMI milk samples were not accurately enumerated by qPCR compared with plate counting of the nonpreserved, raw milk sample. The detection limit of the qPCR protocol of inoculated Staph. aureus ATCC 29213 in bronopol-preserved milk samples was 1.04×10 cfu/mL. The qPCR protocol can be a high-throughput and rapid diagnostic assay to accurately detect Staph. aureus IMI from bronopol-preserved milk samples compared with a traditional culturing method. However, the proposed qPCR protocol is not accurate for counting of Staph. aureus in bronopol-preserved milk samples from naturally infected mammary glands

Effect of the kappa-casein gene polymorphism, breed and seasonality on physicochemical characteristics, composition and stability of bovine milk Efeito do polimorfismo do gene da kappa-caseína, da raça e da sazonalidade sobre as características físico-químicas, de composição e de estabilidade do leite bovino

The objective of this study was to evaluate the effect of genetic polymorphism of kappa-casein, breed and seasonality on the physicochemical characteristics, composition and stability of milk in commercial dairy herds. A total of 879 milk and blood samples were collected from 603 Holstein and 276 Girolando cows, obtained during rainy and dry seasons. Milk samples were analyzed to determine the physicochemical characteristics, composition and ethanol stability, while blood samples were subjected to polymerase chain reaction to identify the kappa-casein genotype. The frequencies of genotypes AA, AB and BB of k-casein were respectively, 66.83, 31.84 and 1.33% for Holstein, and 71.38, 27.90 and 0.72% for the Girolando cows, respectively. The A allele was more frequent than the B allele, both for Holstein (0.827 and 0.173) and Girolando cows (0.853 and 0.147), respectively. Cows of AB and BB genotypes showed a higher milk fat content compared to the AA genotype. There was an interaction between breed and seasonality on the concentration of milk urea with higher values for Holstein and Girolando cows in the rainy and dry season, respectively. The levels of lactose, total solids, crude protein, true protein, casein and the casein:true protein ratio were higher during the dry season, while during the rainy season, the somatic cell count and milk urea concentration were higher. There was no association between milk stability and k-casein genotypes, but Holstein cows showed higher milk stability than Girolando cows, and milk was more stable during the rainy season than during the dry season.<br>Objetivou-se avaliar o efeito do polimorfismo genético da kappa-caseína, da raça e da sazonalidade sobre as características físico-químicas, a composição e a estabilidade do leite bovino de rebanhos comerciais. Foram coletadas 879 amostras de leite e de sangue de 603 vacas da raça Holandesa e 276 da raça Girolando, obtidas durante as estações seca e chuvosa. As amostras de leite foram analisadas para determinação de características físico-químicas, de composição e de estabilidade ao etanol, e as amostras de sangue foram submetidas à reação em cadeia da polimerase para identificação do genótipo da kappa-caseína. As frequências dos genótipos AA, AB e BB da kappa-caseína foram, respectivamente, de 66,83; 31,84; e 1,33% para a raça Holandesa e 71,38; 27,90; e 0,72% para a Girolando. O alelo A foi mais frequente que o B, tanto para a raça Holandesa (0,827 e 0,173) quanto para a Girolando (0,853 e 0,147). Vacas dos genótipos AB e BB apresentaram maior teor de gordura no leite que as do genótipo AA. Houve interação entre raça e sazonalidade para a concentração de ureia do leite, com maiores concentrações para as raças Holandesa e Girolando, respectivamente, nas estações chuvosa e seca. Os teores de lactose, sólidos totais, proteína bruta, proteína verdadeira e caseína e a relação caseína/proteína verdadeira foram maiores durante o período seco, enquanto, durante a estação chuvosa, a contagem de células somáticas e os teores de nitrogênio ureico no leite foram maiores. Não houve associação entre a estabilidade do leite e os genótipos da kappacaseína, no entanto, o leite de vacas Holandesas é mais estável que o de vacas Girolando e, durante a estação chuvosa, apresenta maior estabilidade que na estação seca

Productive performance and milk protein fraction composition of dairy cows supplemented with sodium monensin Desempenho produtivo e composição da fração protéica do leite em vacas sob suplementação com monensina sódica

The objective of this work was to evaluate the levels of sodium monensin on lactating cows and their effects on productive performance and milk protein fraction composition. It was used 12 Holstein cows, distributed in four balanced 3 &#215; 3 Latin squares, and fed three diets: one control without monensin, and two diets with monensin at the levels of 24 or 48 mg/kg DM added to the concentrate. Milk production was daily measured throughout the entire experimental period. The samples used for analysis of milk composition were collected on two alternated days from the two daily milking. Non-protein nitrogen, total nitrogen and non-casein nitrogen contents were directly evaluated in the milk, and casein, whey protein and true protein contents were indirectly determined. The use of monensin in the rations reduced dry matter and nutrient intake, especially when diet with 48 mg/kg of dry matter was given. The ration with 24 mg/kg of DM increased milk production, with or without correction, and also fat and lactose yield, and it improved productive efficiency. The levels of monensin in the ratios did not influence contents of milk crude protein, non-protein nitrogen, non-casein nitrogen, true protein, casein, casein/true protein ratio, whey protein, and of all those fractions expressed as percentage of crude protein. The utilization of monensin in the ratio at the dose of 24 mg/kg of DM influences positively the productive performance of lactating cows, and it does not influence the composition of milk protein fractions.<br>Objetivou-se avaliar níveis de monensina sódica para vacas em lactação e seus efeitos no desempenho produtivo e na composição da fração protéica do leite. Foram utilizadas 12 vacas da raça Holandesa, distribuídas em quatro quadrados latinos 3 &#215; 3 balanceados e alimentadas com três rações: uma controle sem monensina, e duas com monensima nos níveis de 24 mg/kg de matéria seca ou 48 mg/kg MS adicionada ao concentrado. A produção de leite foi mensurada diariamente durante todo o período experimental. As amostras utilizadas para análise da composição do leite foram coletadas em dois dias alternados e provenientes das duas ordenhas diárias. Foram analisados no leite os teores de nitrogênio não-protéico, nitrogênio total e nitrogênio não-caseinoso e indiretamente os teores de caseína, proteína do soro e proteína verdadeira. A utilização de monensina nas rações ocasionou redução do consumo de MS e de nutrientes, especialmente quando fornecida a ração com 48 mg/kg de MS. A ração com 24 mg/kg de MS promoveu aumento da produção de leite, sem e com correção, e da produção de gordura e lactose e aumento da eficiência produtiva. Os níveis de monensina nas rações não influenciaram os teores de proteína bruta, nitrogênio não-protéico, nitrogênio não-caseinoso, proteína verdadeira, caseína, relação caseína/proteína verdadeira, proteína do soro do leite e de todas essas frações expressas em porcentagem da proteína bruta. A utilização de monensina na ração na dose de 24 mg/kg de MS influencia positivamente o desempenho produtivo de vacas em lactação e não afeta a composição das frações protéicas do leite