Culling Policies in Dairy Herds. A Review

The culling decision is one of the most complex decisions in farm animal management. This article reviews concepts of culling, risk factors for cows to be culled, different culling policies and the present knowledge on how to develop an optimal culling policy. It is pointed out that there arc major interactions between other management complexes and culling that influence the result of field research concerning risk factors for culling. The estimated importance of risk factors for culling varies widely in literature. Culling decisions are part of the overall herd management. They cannot be analysed independently. Future research should analyse the interactions between management practices, cow health, economy, and culling in more detail

Risk for the development of Antimicrobial Resistance (AMR) due to feeding of calves with milk containing residues of antibiotics

EFSA was requested to: 1) assess the risk for the development of antimicrobial resistance (AMR) due to feeding on farm of calves with colostrum potentially containing residues of antibiotics; 2) assess the risk for the development of AMR due to feeding on farm of calves with milk of cows treated during lactation with an antibiotic and milked during the withdrawal period, and 3) propose possible options to mitigate the risk for the development of AMR derived from such practices. Treatment of dairy cows during the dry period and during lactation is common in the EU Member States. Penicillins, alone or in combination with aminoglycosides, and cephalosporins are most commonly used. Residue levels of antimicrobials decrease with the length of the dry period. When the interval from the start of the drying-off treatment until calving is as long as or longer than the minimum specified in the Summary of Product Characteristics of the antimicrobial, faecal shedding of antimicrobial-resistant bacteria will not increase when calves are fed colostrum from treated cows. Milk from cows receiving antimicrobial treatment during lactation contains substantial residues during the treatment and withdrawal period. Consumption of such milk will lead to increased faecal shedding of antimicrobial-resistant bacteria by calves. A range of possible options exist for restricting the feeding of such milk to calves, which could be targeting the highest priority critically important antimicrobials. β-Lactamases can reduce the concentration of β-lactams which are the most frequently used antimicrobials in milking cows. Options to mitigate the presence of resistant bacteria in raw milk or colostrum are mainly based on thermal inactivation

Fatores de risco associados à mastite bovina causada por Prototheca zopfii Risk factors associated with bovine mastitis caused by Prototheca zopfii

Este trabalho teve como objetivo o estudo de fatores de risco associados à mastite bovina causada por Prototheca zopfii. Foram analisadas 13 propriedades leiteiras dos Estados do Paraná e de São Paulo, segundo os seguintes critérios de seleção: confirmação prévia de casos de mastite por Prototheca spp., triagem pela pesquisa de Prototheca spp. em tanques de expansão e latões e rebanhos com contagem de células somáticas acima de 5x105cel mL-1. As amostras coletadas consistiram de: leite, água, solo, fezes e swab de teteiras. Prototheca spp. foi isolada de amostras de leite dos quartos mamários com mastite clínica ou subclínica em uma propriedade e de amostras de leite e do ambiente em quatro propriedades, nas quais foi isolada em amostras de: água de bebedouro, abastecimento, esgoto, empoçada no piso de estábulo e sala de ordenha, solo de piquete e pasto, teteiras, fezes de bezerros e suínos. Do total de 383 vacas examinadas, Prototheca spp. foi isolada em 20 (5,2%) vacas, sendo caracterizada como P. zopfii em 18. Os fatores de risco associados à mastite causada por P. zopfii foram: criação das vacas a pasto, alimentação dos animais com pasto e silagem, realização de ordenha mecânica em estábulo, permanência das vacas após ordenha em piquete sem alimento, criação de suínos próxima às instalações dos bovinos, existência de cães, gatos e roedores, falta de higienização dos tetos com água, pré-imersão dos tetos em aplicador com retorno e sem a troca do anti-séptico, alimentação dos bezerros com leite de vacas com mastite clínica e serem as vacas da raça holandesa.<br>This research had as objective the study of risk factors associated with bovine mastitis caused by Prototheca zopfii. Thirteen dairy herds in Paraná and São Paulo states were analyzed and selected according to the following criteria: previous confirmation of Prototheca spp. mastitis cases, screening of Prototheca spp. in bulk tanks and milk cans, and herds with somatic cells count over 5x105cel mL-1. The samples collected consisted of: milk, water, soil, manure and swabs of teat cup rubbers. Prototheca spp. was isolated from mammary quarters with clinical and subclinical mastitis of milk samples in one herd and from the environment and cows in four herds. Out of 383 cows examined, Prototheca spp. was isolated in 20 (5.2%) cows with mastitis, and 18 of them were characterized as P. zopfii. In four herds when Prototheca spp. was identified from mammary quarters and environment the agent was isolated from the following samples: water in the waterers, puddled water in the stalls and the milking parlour, supply, sewage, cow pen and pasture soil, teat cup rubbers and manure from calves and swines. The risk factors associated with P. zopfii mastitis consisted of: pasture system, pasture and silage feeding, use of milking machine in stalls, cow pen without fresh feed after milking, raising of swines near bovine housing, existence of dogs, cats and rodents, absence of teats hygienization with water, use of pre-immersion devices with return and without change of antiseptic, calves fed with milk of clinical mastitis cases and the Holstein breed