UBC Theses and Dissertations
Effects of sawdust bedding dry matter on lying behaviour of dairy cows : a dose dependent response Reich, Lindsey Janelle
The objective of this thesis was to determine the effects of bedding dry matter on lying behaviour of Holstein cows. Over time bedding becomes wet with urine, feces and milk, but no research is available to guide recommendations for farmers regarding how often bedding should be replaced. I carried out two replicates of an experiment testing the effects of varying dry matter content of sawdust bedding systematically over five treatment levels. One replicate was conducted during the summer and one in the winter to test if the effects of damp bedding varied with season. The five bedding treatments averaged (± SD) 89.8 ± 3.7, 74.2 ± 6.4, 62.2 ± 6.3, and 43.9 ± 4.0, and 34.7 ± 3.8% dry matter. Over the course of the trial, minimum and maximum temperatures in the barn were 2.6 ± 2.0 and 6.8 ± 2.2º C in the winter and 13.3 ± 2.5 and 22.6 ± 4.1º C in the summer. In both seasons, five groups of three non-lactating cows were housed in free stalls bedded with sawdust. Following a five day acclimation period on dry bedding, groups were exposed to the five bedding treatments in a five by five Latin square. Each treatment lasted four days, followed by one day when the cows were provided with dry bedding. Stall usage was assessed by 24 hour video scanned at five minute intervals averaged over two days. Responses were analyzed in a mixed model with group as the observational unit. Bedding dry matter affected lying time, averaging 10.4 ± 0.4 hours per day on the wettest treatment and increasing to 11.5 ± 0.4 hours per day on the driest bedding. Lying time varied with season, averaging 12.1 ± 0.4 hours per day across treatments during the winter and 9.9 ± 0.6 hours per day during the summer, but season and bedding dry matter did not interact. These results show that wet bedding reduces lying time in a dose dependent manner during both winter and summer seasons.
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