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Biomedical subjects

D M Broom

Publications and source records attributed to D M Broom.

39 records · Page 3Linked to original sources

Responses of dairy cows to badger urine and faeces on pasture with reference to bovine tuberculosis transmission.

Grazing cattle were observed when they encountered badger urine or faeces which, in all but the first study, came only from badgers which were not infected with bovine tuberculosis. The faeces were very strongly avoided and there was generally a strong avoidance of ingestion of badger urine. There was no evidence that cattle were attracted to badger latrines in an area where some infected badgers were present and cows actively avoided faeces up to 28 days old which was placed on grass turves or on pasture. 99.3% of cows took no bites from small grass plots contaminated with faeces and 88.7% of cows took no bites from urine-treated plots. There was generally avoidance of pasture treated with badger urine up to 14 days old. However, two cows out of 240 were willing to graze close to faeces and seven out of 240 were willing to graze near urine. Contaminated herbage was eaten most when attractive herbage became scarce. Wet weather did not reduce the strength of avoidance of urine. Some cows responded to badger urine, and to a lesser extent to faeces, by more sniffing, particularly when herbage was scarce. The odour of faeces, and sometimes that of urine, often resulted in the ejection of mouth contents. As a consequence of their avoidance of badger faeces and urine, the vast majority of cows are unlikely to contract tuberculosis from infected badgers by ingestion. Most cows totally avoid badger products so they are unlikely to be infected via inhalation. However, the small minority of unselective cows must be more at risk and this finding warrants further investigation.

Animals↗

Brain opioid receptors in relation to stereotypies, inactivity, and housing in sows.

When animals encounter difficult conditions, endogenous opioids are often released and may help in coping with the difficulties. In sows, prolonged confinement results in behavior abnormalities: high levels of stereotypies or excessive inactivity and unresponsiveness. The possibilities of causal links between endogenous opioids and these behavioral indicators of poor welfare have been raised. Mu receptor density was found to be greater in tethered sows than in group-housed sows and to be positively correlated with time spent inactive. There were negative correlations between both mu and kappa receptor densities and stereotypy duration. Kappa agonists are associated with aversion, and there are complex links between endorphin levels, dynorphin levels, and dopamine action. These results provide the first demonstration of a relationship between abnormal behavior in pigs and opioid receptor density, and help to clarify the links between behavioral responses and opioid action.

Analgesics↗