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The effects of a flexible grazing management strategy and leader/follower grazing on the milk production of grazing dairy cows and on sward characteristics
Author(s) -
MAYNE C. S.,
NEWBERRY R. D.,
WOODCOCK S. C. F.
Publication year - 1988
Publication title -
grass and forage science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 56
eISSN - 1365-2494
pISSN - 0142-5242
DOI - 10.1111/j.1365-2494.1988.tb01881.x
Subject(s) - grazing , stocking , zoology , ice calving , milk production , stocking rate , biology , yield (engineering) , agronomy , mathematics , lactation , pregnancy , physics , genetics , thermodynamics
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.