3 May 2008

6 minute read

Although recent increases in beef prices indicate a strengthening beef market these price increases are largely offset by increased concentrate prices highlighting the necessity to maximise beef output from grazed grass.

Early turnout of beef cattle to grass is critical to control costs in beef production. Dr Frances Lively checks sward height at AFBI Hillsborough.

Good grassland management is essential to maximise beef output, with the main objectives of grassland management being to produce high yields of grass and to manage the grass and the cattle to ensure a high intake and a high level of animal performance, while at the same time avoiding under-utilization of the sward and wastage of grass. These objectives are best achieved by turning cattle out as early as is practicable in the spring and maintaining the correct sward height (9 cm) throughout the grazing season, so that cattle feed requirements are closely matched to the rate of grass growth.

Recent increases in fertiliser and fuel costs have increased the cost of producing grass this season. However, relative to other feedstuffs, grazed grass still remains the cheapest source of feed for beef cattle. This is supported by recent data from the Home Grown Cereals Authority (HCGA), which have shown that current cereal prices are approximately double last years prices and, as a result, high concentrate input systems of beef production are not an economically viable option. On this basis it is critical to fully utilize all grass available for grazing by using a high level of grassland management.

Turnout Date

Early turnout of cattle to grass is critical to good grassland management. Department of Agriculture and Rural Development (DARD) funded research undertaken at the Agri-Food and Biosciences Institute (AFBI) Hillsborough site has clearly shown improved animal performance by turning both finishing and store cattle out to pasture early. In one study continental bullocks turned out to pasture 6 weeks earlier i.e. on 14 March, produced carcasses 23 kg heavier than their counter parts which remained indoors on grass silage and concentrates until 2 May. Taking an average carcass price of £2.35, this equates to an additional £55 per head. In another more recent study, store bullocks turned out to pasture 3 weeks earlier on 5 April were 23 kg live weight heavier at housing than their counterparts which remained housed until 22 April. Following a second winter finishing, differences due to turnout date were reduced to 8 kg live weight or 5 kg carcass weight. Taking an average carcass price of £2.35, this equates to an additional £12 per head. These results indicate that turning cattle out to pasture up to 6 weeks early in spring can offer substantial economic benefits in beef production. In addition to improved animal performance, early turnout reduces production costs by reducing the requirement for winter feed as well as the volume of slurry to spread.

Sward Quality

During the grazing season it is essential to manage the stocking rate in line with grass growth to ensure cattle have access to a high quality grass sward. This is best achieved by ensuring grass growth equals grass demand. Latest information on grass growth is published weekly in Grass Check. Grass quality depends on the stage of maturity of the plant that can be determined from the height of the sward. As grass grows the proportion of stem within the plant increases. A sward of long stemmy grass has a lower nutritive value and is less palatable than a short green leafy sward. Grazing the sward down tight in the early grazing season minimises seed head production and promotes a leafy sward for the rest of the season. Maintaining appropriate sward heights to maximise grass utilisation and animal growth potential are more easily achievable in a rotational grazing system compared to set stocking system, as paddocks can be taken out for silage production during periods of high grass growth. In a rotational grazing system, to achieve maximum levels of gain with high levels of grass utilisation, swards should be grazed down to 6 cm during spring – early summer, increasing to 8 cm in late summer and 10 cm in autumn.

DARD funded research undertaken at AFBI Hillsborough has demonstrated that in a set stocking system, grass height should be maintained at 9 cm to maximise beef cattle performance. In these studies sward heights from 6.5 cm to 11 cm were evaluated for animal performance and grass utilisation. As illustrated in Figure 1, reducing the sward height from 11 to 9 cm had no effect on animal performance but a further reduction to 6.5 cm reduced live weight gain by 30%. Grazing at 6.5 cm sward heights lead to all grass being grazed including the clumps around the dung pats. With a height of 9 cm the sward was reasonably well grazed down, whilst at the 11 cm sward height large areas were only partially grazed or ungrazed which lead to a lot of dead grass at the base of the sward thath rotted away and was lost. Consequently grazing at a sward height of 9 cm facilitates high levels of grass utilisation and animal performance in a set stocked system.

Concentrate Supplementation at Pasture

The response to concentrate supplementation at pasture depends on grass supply. As shown in Figure 1, offering 1.6 kg concentrates per head per day did not affect the performance of beef x dairy calves grazed at 9, 10 or 11 cm, but increased gain of those grazed at a sward height of 6.5 cm by 13%. Research undertaken at Grange Research Centre on finishing beef cattle showed a similar response to feeding concentrates at pasture, with only cattle on a very high stocking rate showing an economic improvement with concentrate supplementation throughout the grazing season. Therefore concentrate supplementation at pasture will not improve animal performance if there is an adequate supply of good quality grass available.

Summary

• Whilst Grass Check has shown lower grass growth than normal in spring 2008, early turnout is still critical to reduce costs of beef production
• 6 week earlier turnout of beef cattle increases carcass gain by 0.47 kg per day
• 3 weeks earlier turnout of store cattle increases carcass gain by 0.29 kg per day
• For maximum animal performance and grass utilisation maintain beef cattle at 9 cm sward height throughout the grazing season in continuous grazing system or at 6, 8 and 10 cm sward height for spring, summer and autumn grazing respectively, in a rotational system
• If grass supplies are adequate concentrate supplementation of beef cattle at pasture is of no benefit.

Figure 1. Effect of sward height under continuous grazing on live weight gain of calves (kg per calf per day).