ISSN:
1365-2494
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
An experiment was carried out during 1984 to examine the effects of three alternative grazing strategies for January/February calved British Friesian dairy eows on sward and animal production. Cows were rotationally grazed across 1 d paddocks without concentrate supplementation from 30 April to 1 October. A flexible grazing (EG) treatment involved manipulating residual herbage height, as assessed by a rising-plate sward stick, with cows initially grazing to 80 mm, reducing to 60 mm when milk yield declined below 20 kg d−1 and finally to 50 mm when milk yield declined below 15 kgd−1. Control (C) cows grazed to a constant residual herbage height of 60 mm throughout the season (a 60-inm rising-plate sward stick height is equivalent to a sward surface height of approximately 80 mm). On a further treatment a leader/follower (LF) approach was used, with cows paired for calving date and parity and within pairs allocated to either a high-(leader) or a low-yielding (follower) group, according to milk yield at turnout, with the leader group grazing 1 d ahead of the follower group. Overall stocking rates on C and LE treatments were identical but herbage allowances differed as a result of treatment effects.Animal performance data for the FG, C and LE treatments, respectively, were: milk yield (kg d−1) 14·5, 14·7 and 16·0 (s.e. 0·59); milk fat yield (g d−1) 577, 571 and 637 (s.e. 29); milk protein yield (g d−1) 528, 527 and 576 (s.e. 19); and liveweight gain (kg d−1) 0·09, 0·20 and 0·14 (s.e. 0·04).Overall, there was no benefit in animal production following lax grazing in spring even with high-yielding cows, and this approach resulted in the accumulation of stem and senescent material in the sward in mid-season. However, preferential treatment of high-yielding cows by grazing as a leader group in a leader-follower system resulted in higher milk production, particularly in late season, with an overall improvement in milk yield for the LF treatment of 9% relative to treatment C.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2494.1988.tb01881.x
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