Early pairing (3 d of age) increased solid feed intake and weight gains in comparison to late-pairing (42 d of age) and individual housing. From 0 d to 28 d of age calves in all treatments received 8 L/d of pasteurized whole milk, divided in 2 feedings, delivered at 0800h and 1630h.
In Chapter 4, I investigated how individual housing of calves affects food neophobia. Early pair housing increases solid feed intake and weight gains in dairy calves. From d 29 to d 49 calves were fed 6 L/d, fed as described above.
I conclude that calves raised in more complex social environments early in life experience benefits related to feeding behaviour development, performance, ability to cope with novelty, and that experienced companions can be used to mitigate stress associated with novelty. Trial 1 - Hay Trial 2 - Carrots Variables Individual Social Individual Social Intake (g / test) Days 1 17 ± 8.1 34 ± 8.1 6 ± 9.1 27 ± 8.6 2 14 ± 8.1 47 ± 8.1 8 ± 9.1 26 ± 8.6 3 22.5 ± 8.1 24 ± 8.6 5 ± 9.1 29 ± 9.1 Latency to eat (min:s) 1 ± ± ± ± 2 ± ± ± ± 3 ± ± ± ± 45 Table 4.
iii Preface I completed this thesis under the supervision of Dr. Least squares mean (±SE) latency (mm:s/test) to approach the feed, latency (mm:s/test) to approach the empty bucket, time (mm:s/test) spent eating and time (mm:s/test) spent manipulating empty bucket. Calves were assigned to housing either in a complex social group with the dam and other cows and calves or individual rearing.
In Chapter 4, I investigated how individual housing of calves affects food neophobia. Calves were assigned to housing either in a complex social group with the dam and other cows and calves or individual rearing.
The results suggested that calves raised in a complex social environment are less reluctant to ingest new feed types. In Trial 1 (n=10 per housing treatment) calves were tested with exposure to a novel hay and in Trial 2 (n=8 per treatment) calves were tested with chopped carrots. Analyses were based upon square-root transformed data; back-transformed data are presented.
............................................................................................................ Results are from individually housed calves (n = 18).
Analyses were based upon the predicted intake of each particle fraction measured as disappearance after 24 h feeding.Chapter 5 investigated whether being grouped with experienced dairy cows would affect the development of grazing behaviours in pregnant dairy heifers first introduced to pasture. von Keyserlingk and Jennifer Black, all from the University of British Columbia. Latency to eat (min:s)1 - Hay 2 - Carrots Trialb)0153045Average intake (g/test)1 - Hay 2 - Carrots Triala)Individual Social 44 Table 3.The results indicated that grouping heifers with pasture-experienced cows improves grazing behaviour in the first hours following introduction to pasture. The studies described in this thesis were approved by the University of British Columbia’s Animal Care Committee (AUP A12-0337). Least squares mean (± SE) intake of novel feed (g/test) and latency to eat (min:s) during 3 consecutive days of testing.Standard practice within the dairy industry is to separate calves from the dam immediately after birth and raise calves in individual pens during the milk-feeding period with little or no contact with conspecifics. A version of Chapter 4 has been published: Costa, J. For early-paired calves, 2 calves were paired at 6 ± 3 days of age by having the barrier to the neighbouring pen removed to create a double pen.I reviewed empirical work (Chapter 2) on the social development of calves, the effects of social isolation and the practices associated with group housing of dairy calves. For late-paired calves, the individual housing continued until the age of 43 ± 3 d, 14 d before weaning.