Recovery from Mastitis in Dairy Cows – Development of Behaviour, Milk Production and Inflammatory Markers in the Weeks during and after Naturally Occurring Clinical Mastitis

Publikation: Bog/antologi/afhandling/rapportPh.d.-afhandlingForskning

  • Katrine Kop Fogsgaard, Danmark
Mastitis results from invasion of infectious pathogens into a mammary gland and constitutes a significant problem in dairy herds around the world. In addition to economic consequences for the farmer, episodes of clinical mastitis in dairy cows are associated with discomfort and increased risk of culling and death. Although mastitis has received significant scientific attention, one aspect of bovine mastitis has only been touched upon very briefly; the characterization of the recovery period and its potential for modulation.
Hence, in order to increase the understanding of the recovery period after bovine mastitis and to create a basis for future facilitation of recovery, the present thesis focussed on two selected aspects of recovery; a behavioural as well as an inflammatory aspect, aiming to 1) describe the behaviour of dairy cows in the days before, during and after antibiotic treatment for naturally occurring mastitis and to compare with behaviour of healthy cows; 2) describe the development within milk production and inflammatory markers before, during and after antibiotic treatment of naturally occurring mastitis, and to compare with healthy cows, with special focus on the expected post-mastitis stabilisation within these measures and 3) investigate a possible relationship between behaviour, milk production and inflammatory markers during naturally occurring bovine mastitis and its early recovery. Overall, the focus was on dairy cows housed in free stalls with automatic milking systems (AMS). This type of housing is gaining ground in the modern dairy farm. Furthermore, these settings are well suited for studies, like the present, where the use of automatically recorded measures are prioritised.
The aims were achieved by two studies, the results of which are described in three papers included in this thesis. Study 1 was a cohort study using matched pair design where clinical registrations, production data and automatically recorded behavioural and inflammatory measures were collected prior to, during and after antibiotic treatment of naturally occurring mastitis. Based on 30 mild cases without systemic symptoms, the daily activity, feed intake and behaviour during milking of the infected animals were shown to differ from the healthy controls. For the majority of the examined behavioural measures, a lack of stabilisation during the week after finalisation of antibiotic treatment was found, suggesting that even within relatively mild cases of clinical mastitis, the cows were not recovered within this time frame. The description of the inflammatory aspect of mastitis focussed on changes in milk yield and inflammatory markers. Based on Study 1, the local clinical symptoms faded after antibiotic treatment but persisted for at least a week afterwards, which may have affected the welfare of the cows. The results of Study 2, involving automatically recorded measurements of milk yield and inflammatory markers from 174 mastitic and 858 control lactations, confirmed the findings of Study 1 and showed that milk yield, inter-quarter milk yield ratio and lactate dehydrogenase activity stabilised within one to three weeks post antibiotic treatment, but did not reach the pre-mastitis levels during the observation period of eight weeks post-mastitis. Hence, mastitis had a long-term effect on the measured variables and the infected cows were not fully recovered within eight weeks after antibiotic treatment.
The presented combination of inflammatory as well as behavioural aspects of the recovery from bovine mastitis is new, and these results provide a more complete description of the recovery status of individual cows after a mastitis infection than what has been available until now. The co-development within the measures obtained in Study 1, which has been described in Paper III, e.g. showing a negative relationship between clinical score and lying time, has not been described before and may be considered as a first step to increase the understanding of the effect of mastitis infections in terms of animal welfare.
Overall, the results of the present thesis show that dairy cows with clinical mastitis have only partly recovered eight weeks after antibiotic treatment – measured on behaviour, milk production and inflammatory markers. Although some of the measures stabilised, a lack of normalisation to pre-mastitis levels was found, indicating that the cows did not fully recover within the observation period of up to eight weeks. Future studies are needed to clarify the possible consequences of the long recovery period in terms of animal welfare, as well as to investigate whether recovery can be facilitated by e.g. environmental (the use of hospital pens or special care), pharmacological (the use of pain relief) or nutritional initiatives.
Antal sider113
ISBN (Trykt)978-87-93148-00-0
StatusUdgivet - mar. 2015

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