An evaluation of the effects of grazing management systems involving preferential treatment of high‐yielding dairy cows on animal performance and sward utilization

Abstract

Two systems of grazing management involving preferential treatment of high-yielding dairy cows were compared with a grazing system in which both high-and low-yielders received uniform treatment. Cows were rotationally grazed across I-day paddocks without concentrate supplementation from 23 April to 8 October 1985, with a mean stocking rate over the season of 5-4 cows ha'. Preferential treatment of high-yielding cows was achieved either by using a leader/follower approach (LF) with highyielding cows in the leader group, or by preferential forage feeding (PFF) where high-yielding cows were allowed access to grass silage for 1 -5 h daily and grazed alongside low-yielders. Control (C) cows grazed together as a single group. The high grazing stocking rates used on all three treatments resulted in good grass utilization with residual sward heights, assessed by a rising-plate sward stick, of 45, 50 and 48 mm for the LF, PFF and C treatments respectively. Animal performance data for the LF, PFF and C treatments respectively were: milk yield (kg d"') 15-1, 15-6 and 14-7 {s.e. 0-78); milk fat yield (g d " ') 598, 606 and 567 (s.e. 34); milk protein yield (g d " ') 500, 519 and 480 (s.e. 31); and liveweight gain (kg d "') 0-12, 0-23 and 0-25 {s.e. 0-05). These results indicate that leader/follower grazing had little overall effect on animal performance when high grazing tCorrespondence and preseni address: Dr C, S, Mayne, Agriculiural Research Insitiuie of Nonhern Ireland, HJllsborough. Co. Down, BT26 6DR, UK, severity was imposed, with the improvement in animal performance cf high-yielding cows in the leader group being offset by the reduced performance of the follower group. Buffer-feeding of high-yielding, rotationally-grazed cows with high-quality grass silage had little effect on animal performance and resulted in a decrease in the efficiency of grassland utilization. Silage appeared to substitute for herbage, with a reduction in herbage DM intake of 0-55 kg per kg silage DM consumed.

The effects of offering a range of forage and concentrate supplements on milk production and dry matter intake of grazing dairy cows

“…The substitution rates were similar for each forage supplement (overall forage supplement mean of 0AE57) and were within the range reported for forage supplements in the literature, with values ranging between 0AE2 and 1AE2 kg DM kg )1 supplement DM (Phillips and Leaver, 1985;Roberts, 1989). Mayne et al (1990) reported that supplementation with grass silage to grazing dairy cows resulted in a substitution rate of 0AE55 kg DM intake kg )1 silage DM consumed. Woodward et al (2002) reported substitution rates of 0AE10 and 0AE14 for cows supplemented with grass silage and maize silage, respectively, but this low substitution rate was primarily a reflection of the restricted pasture allowance that the cows were offered in the study.…”

“…The substitution rates were similar for each forage supplement (overall forage supplement mean of 0·57) and were within the range reported for forage supplements in the literature, with values ranging between 0·2 and 1·2 kg DM kg −1 supplement DM (Phillips and Leaver, 1985; Roberts, 1989). Mayne et al. (1990) reported that supplementation with grass silage to grazing dairy cows resulted in a substitution rate of 0·55 kg DM intake kg −1 silage DM consumed.…”

Sward characteristics, grass dry matter intake and milk production performance is affected by timing of spring grazing and subsequent stocking rate

“…The interaction for PDIN balance approached significance as the LH treatments had lower PDIN compared to the other treatments. Meijs and Hoekstra (1984) and Mayne et al (1990) showed that cattle select their diet from the horizon above 45 mm even where high grazing pressures are applied. Hurley et al (2005) found greatest differences were displayed in leaf and stem proportions within the Table 4 Effect of grazing date (GD) and stocking rate (SR) on milk yield, milk composition, bodyweight and body condition score of grazing dairy cows mid-grazing horizon between (80-150 mm) extended tiller height throughout the grazing season.…”

GrazeIn: a model of herbage intake and milk production for grazing dairy cows. 2. Prediction of intake under rotational and continuously stocked grazing management

“…(1979), King and Stockdale (1984), Meijs and Hoekstra (1984), Stakelum (1986a,b,c), Mayne et al. (1987, 1988), Grainger and Mathews (1989), Mayne et al. (1990), Hoden et al.…”