Combining an active transponder system with sprayed n-alkanes to quantify investigative and ingestive grazing behaviour of dairy cattle in pastures treated with slurry

This paper explores the interaction of grazing pregnant dairy cattle (lactating and non-lactating) with contaminated pasture. Behavioural responses were divided into investigative and ingestive grazing events. Patches of sward were artificially contaminated with slurry (containing faeces and urine) and were used to test the behavioural interactions; faecal collection bags ensured no further contamination occurred throughout the two 1-week periods of the experiment. Investigative behaviour was quantified using an active transponder system with aerials buried around the contaminated patches. Ingestive behaviour was quantified using n-alkane markers sprayed on the contaminated patches. The cattle preferentially grazed the uncontaminated sward and this created a trade-off between the non-contaminated and contaminated areas. There was a large variation between cows in both investigative and ingestive behaviour, consequently the effect of physiological state was not significant (P>0.05). As the proportion of faecally contaminated to uncontaminated pasture increased, there was a significant (P