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Research article2009Peer reviewedOpen access

Scientific opinion on welfare of dairy cows in relation to uder problems based on risk assessment with special reference to the impact of housing, feeding, management and genetic selection

Algers, Bo; Blokhuis, Harry; Bötner, A; Broom, DM; Costa, P; Domingo, M; Greiner, M; Hartung, J; Koenen, F; Müller-Graf, C; Raj, M; Morton, DB; Osterhaus, A; Pfeiffer, DU; Roberts, R; Sanaa, M; Salman, M; Sharp, JM; Vannier, P; Wierup, Martin

Abstract

Following a request from the European Commission, the AHAW Panel was asked to deliver a Scientific Opinion on the welfare of dairy cows, considering whether current farming and husbandry systems comply with the requirements of and welfare of dairy cows from the pathological, zootechnical, physiological and behavioural points of view. Due to the great diversity of topics and the huge amount of scientific data, it was proposed that separate scientific opinions on different welfare subjects would be more adequate and effective. Therefore, it was agreed to subdivide the risk assessment process into four different subjects: i) metabolic and reproductive disorders, ii) udder disorders, iii) leg and locomotion problems and iiii) behaviour, fear and pain. A fifth scientific opinion integrates conclusions and recommendations from the scientific report with the outcomes from the four separate risk assessments. The scientific opinion on welfare of dairy cows in relation to udder problems, based on a risk assessment with special reference to the impact of housing, feeding, management and genetic selection, was adopted by the AHAW Panel on 05 June 2009. In the risk assessment four different farming scenarios were considered: 1) cubicle houses; 2) tie-stalls; 3) straw yards; 4) pasture. Identified hazards were classified under (a) housing, (b) nutrition and feeding, (c) management and (d) genetics. The risk assessment outcomes for each of these four classes of hazards were determined and the four different farming scenarios compared. When comparing the different farming systems it can be concluded that the risk of suffering udder problems is independent of the housing system. In the risk assessment, whenever differences between farming systems were present, these were related to the values of risk estimate and magnitude of the adverse effect and not to the ranking of hazards. In addition, it was concluded that housing and management hazards are more likely to cause udder problems that affect welfare, than nutrition-feeding and genetic selection hazards. According to the scoring system used in this analysis, the most important hazard in relation to the housing was the lack of facilities for cows with systemic mastitis, capable of causing poor welfare due to the increased discomfort, pain and disease duration. The inadequate stall/cubicle design was also very highly ranked, especially in cubicles and tie-stalls. If cubicles are too narrow, movement difficulties and teat trampling may occur. Bedding hygiene is also very important for udder health. Infectious udder disorders may occur more in straw-yards where insufficient attention is given to hygiene of the bedding. If stocking density in straw yards is too high, this may lead to teat trampling. In the risk assessment, the inadequate bedding showed a high magnitude of the adverse effect in all systems but the risk estimate was higher in straw yards, followed by tie-stalls then cubicle housing and very low in pasture. Hazards related to nutrition and feeding have very low risk probability to cause udder problems without any difference among the farming systems considered. As regards the management measures for dairy cows, the risk assessment showed that the inadequate treatment and care of animals are the most important hazards for dairy cows. To improve cow welfare, the prevalence of mastitis should be reduced by: the treatment of clinical and subclinical disease, dry cow therapy, identification and elimination of carrier cows, prevention of transmission of infection from cow to cow or through the environment, and improvement of the immune system by minimising stress factors and by a controlled and nutritionally-balanced feed intake. In addition, the inadequate milking procedures (poorly designed or managed milking equipment) lead to teat injury, pain and udder disease in dairy cows. Cow welfare is also poor when stockpersons behave harshly or inconsistently to cows during collection of cows, milking and post milking movement. Robotic milking systems have the potential to improve cow welfare, provided that they are accurately adjusted and carefully supervised, because some cows can select the milking time and the equipment can be accurately adapted to the cow. However, robotic milking systems can be badly managed and some cows may be subjected to long waiting times. In the risk assessment, genetic selection for high milk yield with insufficient emphasis on other traits relating to fitness showed a relatively low risk of causing udder problems in comparison with some management factors and no differences were observed among the different housing systems analysed. The genetics of mastitis resistance in dairy cattle has been studied for a long period. Most studies have focused on milk somatic cell count or clinical mastitis records as the phenotypic measure to account for mastitis resistance. Somatic cell count and clinical mastitis have a large genetic component, are genetically correlated, and many data on them are readily available. Mastitis resistance is genetically antagonistic to production traits, and there is increasing economic justification to include the trait in the breeding objectives for the breeds. Therefore many breeding programmes have included somatic cell count, clinical mastitis, or both, in recent decades, as a way to improve resistance to intra-mammary infections

Keywords

animal welfare; dairy cows; udder; mastitis; risk assessment; housing; nutrition and feeding; management; genetic selection; farming systems

Published in

EFSA Journal
2009, article number: 1141
Publisher: EFSA