Explore
Communities in English
Advertise on Engormix

Making the most out of forage in beef production systems

Published: February 6, 2007
By: RAYMOND JONES - Institute of Grassland and Environmental Research, UK (Courtesy of Alltech Inc.)
The meat sector contributes some £5.5 billion or about 40% to the value of UK agricultural gross output. Of this total, beef accounts for approximately £2 billion by value. In the United Kingdom, over two-thirds of the agricultural land is suitable only as grassland. A large proportion of the grass is fed, either fresh or conserved, to beef cattle.

Although grassland represents one of the cheapest feeds for beef production systems, there are inherent disadvantages associated with grass feed in terms of feed intake, reduced utilisation of dietary energy and protein (Entec, 1997) compared to high cereal (concentrate) diets and often carcasses with high fat:protein ratio. As UK agriculture is moving towards more extensive feeding systems these are important concerns for the beef industry. It is therefore imperative that we optimise the efficiency of utilisation of these grassland-based feeding systems and produce a leaner and hence a more consumer acceptable product. This report will therefore consider methods of improving utilisation of forage-based diets and demonstrate some benefits of using a range of forages to meet the nutritional demands from beef production systems and potential improvements in carcass quality.

The range of gross margins associated with different beef suckler systems in the UK is shown in Table 1. These data highlight some important issues in terms of potential profitability in beef production systems. The low returns for hill-finished beef systems show the importance of government subsidies. In extensive silage beef systems the margins indicate an extremely high variance between the top and bottom producers reflecting the variation in silage quality. Recent data from Ireland has also confirmed the variance in forage quality with average carcass production on farms yielding 553 kg/ha/pa compared to potential of 1000 kg/ha/pa as shown in research trials.

In a recent extensive low input heifer production trial conducted by Dr. N. Yarrow at IGER North Wyke research station, a 60% increase in gross margin per head was shown relative to the MLC Signet UK average. More importantly, the cost per kg of live weight gain for the extensive-reared heifer was £0.63 compared to £0.75 for the Signet National average. The Extensive IGER system used 82 kg/ha fertiliser N compared to 231 kg/ha for the Signet National average. This trial highlights the potential to improve profitability in beef production systems when forages are utilised efficiently.


Table 1. Gross margins (£/ha) of UK suckler beef systems.

Making the most out of forage in beef production systems - Image 1
MLC Beefplan, 1999.


Forage crops for beef production

SUITABLE SPECIES

Red clover (Trifolium pratense)

Red clover is a versatile, high-yielding forage legume crop that can can tolerate a wide range of soil types and can be grown successfully in many areas of the UK. In the past red clover was considered a short-term crop, but new, more persistent varieties with improved pest and disease resistance are now available.


Lucerne (Medicago sativa)

Lucerne (or alfalfa) has perhaps the highest yield and protein potential of all the forage legumes, but has been perceived as unsuitable for many areas in the UK. Lucerne is a deep-rooting crop, making it particularly suited to drier areas and to the recent run of warmer, drier summers (one of the predicted consequences of global warming). These attributes are reflected in the growing commercial interest in the crop.


Lotus (Lotus corniculatus)

Lotus (or birdsfoot trefoil) is a slow growing forage legume, best suited to poorly drained soils or soils with low fertility where it can compete more successfully with weed species. Lotus species have a weak seedling emergence and are usually slow in establishment, a factor that has deterred many producers from experimenting with the crop.


Sainfoin (Onobrychis viciifolia)

Sainfoin is a forage legume that requires welldrained soils that are thoroughly alkaline to depth. Some suitable UK sites for sainfoin are the chalk or limestone areas in the Cotswolds, Salisbury Plain and East Anglia. It is an upright crop suited to conservation.


Forage peas (Pisum sativum)

Whole-crop forage peas have potential as a high yielding short-term crop with a high crude protein content. Forage peas can be grown and ensiled as a pure sward or as a cereal/pea bi-crop, and can be used as a nurse crop for grassland reseeds.


Field beans (Vicia faba)

Field beans also have potential as a high-yielding, high-protein forage crop for ruminants and, like forage peas, are attractive as a break-crop in an arable rotation.


Lupins (Lupinus sp.)

Lupins are not traditionally grown as a field crop in Britain, but progress has been made in identifying determinate types and varieties with a high level of winter hardiness (Fox and Milford, 1996). Thus, varieties suited to significant parts of England and Wales are now available and maps have been produced identifying suitable areas (Milford and Shield, 1996). The grain has a crude protein content of about 440 g/kg DM and Moss and Grundy (1996) found some 0.4 of this to be UDP, approaching the value for soyabean meal. The content of antinutritional metabolites is low. There is a need for more direct information on the nutritive value of lupins grown in the UK but interim results indicate possibilities for substantial replacement of fish meal and soyabean meal in the diets of high yielding cows (Mansbridge and Blake, 1998). With prospects for further improvement through breeding and better agronomy, there is potential for this crop to make a major contribution to ruminant feeding in Britain.


ESTABLISHMENT

Establishment details for the alternative crops described above grown under experimental conditions are summarised in Table 2. In each case soil phosphate and potash indexes were raised to 2+ or 3 and the soil pH was raised to 6.5 prior to sowing (ADAS, 1983). Nitrogen (90 kg/ha) was applied to the kale, but the other crops received no fertiliser N. The lucerne, lotus and sainfoin seed required inoculation with species-specific Rhizobia meliloti prior to sowing. All the crops were established in May.

In general, the costs of establishing forage legumes are comparable with those for establishing grass leys. The seed costs are broadly similar, and any costs associated with extra applications of lime, herbicide and K2O are offset by savings from not applying fertiliser N. However, in addition to the herbicide listed, the field beans required multiple applications of a fungicide (C-Flo 2) and an insecticide (Aphox) to maintain a clean crop. Not only did the disease and insect infestations encountered pose a significant threat to the overall success of growing this crop, their treatment added substantially to the variable costs of establishing this crop.


Table 2. Establishment of alternative crops.

Making the most out of forage in beef production systems - Image 2


YIELD

Total annual yields over three years for the forage legumes are shown in Table 3. In the case of red clover and lucerne, the values are the sum of the yield from three cuts for conservation, plus an estimate of yield for aftermath grazing of lucerne in years 2 and 3. These yields compare well with quoted values of 14.3 t DM/ha for a perennial ryegrass (cv. Fennema with 350 kg N/ha applied) and 15.6 t DM/ ha for Italian ryegrass (cv. Atalja with 400 kg N/ha applied) (NIAB, 1997).


Table 3. Total annual DM yield of forage legumes (kg/ha).

Making the most out of forage in beef production systems - Image 3
1re-sown with cv. Upstart
2re-sown with cv. Cotswold Common



Although the establishment year yield of the lotus was good, winter persistency was poor, and the area was re-sown with a different variety the following year. The yield of this second variety was lower than that of the Leo cultivar, and it also failed to persist.

The yield and persistency of the sainfoin was also poor, reflecting the unsuitability of the agronomic conditions under which it was being grown.

Kale was found to consistently yield around 6 t DM/ha, irrespective of harvest date. Likewise, the DM yield of forage peas was found to be similar at 10 weeks growth (first pod set) and 14 weeks growth (pod fill) (Table 4), due to the more mature crop lodging. In contrast, there was a significant increase in the DM yield of field beans over the same time period.


Table 4. Effect of harvest date on the DM yield of forage peas and field beans (kg/ha).

Making the most out of forage in beef production systems - Image 4


PROTEIN CONTENT

The majority of the alternative crops listed were found to have crude protein contents in excess of 20%. The two exceptions were kale (11% CP), probably due to low N inputs, and sainfoin (14 % CP), probably due to the poor establishment.

One of the major problems with grass and grass silage as a protein source for ruminants is the high proportion of rapidly degraded protein, coupled with a lack of synchrony with available energy, which may lead to large losses of N as excreta. If the nitrogen within the forage is maintained in a less degradable form, or is protected, the efficiency of utilisation is likely to be improved.

Lotus, sainfoin, forage peas and field beans contain significant amounts of condensed tannins. These compounds can protect plant protein from natural degradation in the rumen (Waghorn et al., 1987). Tannins also prevent foam production, thereby preventing bloat.

Red clover contains polyphenol oxidase enzyme, which can also inhibit protein breakdown in the rumen (Jones et al., 1995; Hatfield and Muck, 1999). This may account for the crude protein in red clover being less degradable in the silo and rumen than that of other legume crops with similar crude protein contents. Detailed monitoring of the ensiling process has shown that differences in degradability between red clover and lucerne can lead to the free amino acid concentrations of lucerne silage being approximately 40% higher than that of red clover silage (Winters et al., 1999), which can lead to substantial losses of N in silage effluent.


MANAGEMENT

Grazing

When grown for grazing, red clover is usually established with a grass companion crop, typically an Italian or hybrid ryegrass. However, maintaining the balance between the crops can be difficult. Early in the season, the grass will grow more quickly than the clover, and shading of the legume may occur. By mid-season the clover will be growing rapidly, and the crop is more easily managed as a silage sward than a grazed sward. Aftermath grazing and grazing later in the season are options, but care must be taken to ensure that excessive trampling does not damage the crop.

Lucerne is not usually grazed except at the end of the season, as it is prone to stock damage. However, new more robust varieties specifically bred for grazing are now becoming available. If the crop is grazed, it is essential that a rotational system is put in place, and that stock is removed in time to allow the crop to accumulate reserves in the autumn.

The growth habit of lotus makes it more suited to grazing than conservation, but research is still required to establish grazing guidelines for this crop. Although there is also comparatively little information available regarding options for grazing sainfoin, there are accounts of sainfoin hay aftermath being successfully grazed.

Many producers strip graze kale to maximise utilisation and minimise wastage. However, stripgrazing has notable disadvantages, especially in wet weather when animal welfare may be compromised (Bradshaw and Borzucki, 1981), and poor stock cleanliness can lead to subsequent rejection by abattoirs. Ensiling kale as baled silage can eliminate many of these problems.


Silage

Red clover and lucerne leys are better suited to conservation management than grazing management, and typically this should consist of two to three main cuts of silage. The first cut should be taken in late May or early June, with a second cut some 6-8 weeks later, and a final cut taken no later than mid October. This latter growth could also be used for grazing for weaned lambs or beef cattle as long as trampling is avoided. The aftermath of kale can also be used for grazing.

Most mowing machines have been designed to mow grass. This has led to the development of harsh conditioners to bruise the grass stems and leaves to encourage wilting (Jones and Fychan, 1999). Forage legumes cannot tolerate this harsh conditioning as it encourages the loss of leaf and pod. Therefore, the cutting of these crops should done with mowers without conditioners or with minimum conditioning using rubber rollers. The cutting height of these forages should be around 100 mm – higher than that conventionally used for grass, to aid regrowth and to avoid soil contamination. Since tedding may exacerbate leaf loss and possible soil contamination, the forage should be left to wilt in swathes.


Ensiling potential

Forage legumes are generally perceived to be difficult to ensile, due to their low water soluble carbohydrate (WSC) content and high buffering capacity. However, all the alternative crops mentioned previously can be successfully ensiled in both clamps and large round bales using new harvesting and conservation technologies. For example, inoculation with Lactobacillus plantarum at ensiling can significantly improve the fermentation characteristics of alternative forages, as illustrated in Table 5.

Evidence suggests that inoculation of grass with lactic acid bacteria before ensiling improves the protein status (Cussen et al., 1995) of the resultant silage and this has been linked to an increased production response in beef cattle (Jones et al., 1996). Several interacting factors are probably involved, including the preservation of more intact forage protein, stimulation of fibre digestion in the rumen and possible probiotic effects of inoculant bacteria. It is likely that the overall benefits of inoculation are similar for alternative protein-rich crops.


Table 5. Effect of inoculation on the fermentation characteristics of alternative forages.

Making the most out of forage in beef production systems - Image 5
Where U = untreated, I = inoculated
*Treatments differ significantly


Ensiling legumes in bales has been perceived to be advantageous due to the rapid sealing of individual bales making efficient use of the limited sugar available; but chopping and clamping can be as efficient as long as good clamp management is adopted and the clamp sealed quickly. Legumes generally have a lower sugar content than grass, and it is therefore essential to wilt these crops and concentrate the available sugars. Wilting of kale and beans may be difficult due to the waxy nature of the kale and the thick stems and fleshy pods of the beans, but all the other forages can be successfully wilted over a 48 hr period. It is beneficial to wrap bales of alternative forage crops in 6 layers of film, especially bales of red clover, lucerne and kale due to the stemmy nature of these crops.


Protein composition and utilisation of ensiled legumes

There are major differences among forages in relation to protein composition and utilisation. White clover and lucerne may have many of the disadvantages of grass silage with low concentrations of WSC and extensive proteolysis during ensiling resulting in silages with low levels of true protein (TP) and high concentrations of free amino acids, illustrated here for lucerne and red clover in Figure 1 (Winters et al. 1999). Free amino acid content was reduced by use of silage inoculant, but was still markedly higher in lucerne than in red clover. Davies et al. (1999), using in vitro rumen simulation technology, concluded that efficiency of microbial-N synthesis was 34% higher in untreated red clover silage compared to untreated lucerne silage. Furthermore, when the red clover silage was treated with a biological inoculant then this difference was even greater. Beever and Thorp (1996) concluded that microbial protein yields were higher for silages made from white clover and lucerne than for grass silages, but this arose largely from high crude protein contents and high levels of feed intake.

Making the most out of forage in beef production systems - Image 6

Figure 1. Free amino acids (moles/kg N) in silages made from lucerne and red clover either untreated or treated with a biological inoculant (adapted from Winters et al., 1999).


Animal performance

ENSILED LEGUMES

Many experiments conducted in the US (Broderick, 1995; Kraiem et al., 1990) and the UK (Jones et al., 2000) have shown improved beef performance from animals fed ensiled legumes compared to grass-only silages. The data shown in Table 6 extracted from a recent trial conducted at IGER highlight improved production from growing steers fed white and red clover silage compared to ryegrass only silage. It is likely that the improved performance was a consequence of higher feed intakes from the legume silage.


Table 6. Effect of silage type on the performance of steers.

Making the most out of forage in beef production systems - Image 7


HEALTHY BEEF

The fatty acid composition of ruminant products has become increasingly important in recent years, because of concerns regarding links between the fatty acid composition of dietary fat for humans and cardiovascular and other lifestyle diseases. IGER beef research has investigated the potential to exploit grass, which contains some 50-75% of the total fatty acids as omega-3 fatty acids (linolenic acid).

Recent research at IGER (Scollan et al., 2000) involved beef steers fed grass silage plus one of four concentrates for 120 days: Megalac (experimental control, rich in saturated palmitic acid), whole linseed (linolenic acid), fish oil (eicosapentaenoic acid and docosahexaenoic acid) and linseed plus fish oil in equal amounts. In comparison to the control (Megalac), feeding linseed doubled the concentration of linolenic acid and significantly enhanced eicosapentaenoic acid in the meat. This work clearly demonstrates that quality feeds can be translated into quality meat.


MEAT APPEARANCE AND FLAVOUR

Increasing the levels of polyunsaturated fatty acids in meat can lead to accelerated colour changes from red to brown due to oxidative changes. Meat samples taken from animals fed fish oil showed higher oxidative change during retail display and faster colour deterioration. However, feeding a linseed (high linolenic acid) diet enhanced the shelf life of the meat. Studies are now progressing to examine ways of enhancing the uptake of omega-3 PUFA from grass based diets, and to study the subsequent effects on meat quality, with the objective of producing healthy beef with enhanced flavour characteristics. Initial observations on the colour saturation of beef steaks stored for 12 days are shown in Figure 2 and there appears to be clear benefits in the shelf life of meat from forage-fed beef steers compared to concentrate-fed steers.

Making the most out of forage in beef production systems - Image 8

Figure 2. Effect of diet on colour saturation of 12 days stored beef loin steaks.


Conclusions

All the crops mentioned have potential for conservation as a home-grown, high protein supplement or substitute for grass silage; and using new harvesting and ensiling technologies it is now possible to reliably produce high quality silage despite the low sugar content and(or) high buffering capacity of most of these crops. The use of biological inoculants on legume crops has shown benefits in terms of fermentation and nutritive value of the crops. There is potential to improve the quality of meat products by feeding high quality forage crops although further studies on the flavour and meat stability issues is warranted.


Acknowledgement

The author wishes to acknowledge data supplied by Dr. Nigel Scollan (IGER) on carcass lipid content and Dr. Mariecia Fraser (IGER) for data on grazing of legume crops.


References

ADAS. 1983. Lime and fertiliser recommendations. No. 5 grass and forage crops. Ministry of Agriculture, Fisheries and Food booklet 2430. Northumberland, UK: MAFF, Chalcombe Publications, Marlow Bottom, Marlow, Bucks.

Beever, D.E. and C. Thorp. 1996. Advances in the understanding of factors influencing the nutritive value of legumes. Occ. Symp. 30, Br. Grassld Soc., pp. 194-207.

Bradshaw, J.E. and R. Borzucki R. 1981. The effect of cultivar and harvest date on the chemical composition and digestibility of fodder kale. J. of the Sci. of Food and Agric. 32:965-972.

Broderick, G.A. 1995. Performance of lactating dairy cows fed either alfalfa silage or alfalfa hay as the sole forage. J. Dairy Sci. 78:320-329.

Cussen, R.F., R.J. Merry, A.P. Williams and J.K.S. Tweed. 1995. The effect of additives on the ensilage of forage of differing perennial ryegrass and white clover content. Grass and Forage Sci. 50:249-258.

Davies, D.R., A.L. Winters, D.K. Leemans, M.S. Dhanoa and R.J. Merry. 1999. The effect of inoculant treatment of alternative crop forages on silage quality and in-vitro rumen function. In: Proceedings of the 12th International Silage Conference (T. Pauly, ed), Uppsala, Sweden, pp. 131-132.

Entec. 1997. Home Grown Protein Sources For Animal Feeds. Leamington Spa, UK, Entec UK.

Fox, K. and G.F.J. Milford. 1996. Improvements in the performance of peas, beans and lupins as grain legumes for British and European agriculture. Occ. Symp. 30, Br. Grassld Soc., pp. 52-61.

Hatfield, H. and R. Muck R. 1999. Characterising proteolytic inhibition in red clover. Proceedings of the 12th International Silage Conference (T. Pauly, ed), Uppsala, Sweden, p. 147.

Jones, R. and R. Fychan. 1999. Efficiency of wilting of temperate grass crops using high performance conditioning. Proceedings of the 12th International Silage Conference (T. Pauly, ed), Uppsala, Sweden, p. 233.

Jones, B.A., R.E. Muck and R.D. Hatfield. 1995. Red clover extracts inhibit legume proteolysis. J. Sci. Food and Agric. 67:329-333.

Jones, E.L., P.A. Evans, A. Cooper, M.S. Dhanoa and N.D. Scollan. 2000. Higher liveweight gains from pedigree steers grazing on grass clover swards. Bgs Occasional Symposium No. 34, pp. 107-109.

Jones, R., A. Winters and J.E. Cockburn. 1996. Changes in amino acid content of additive treated grass silage and its effect on animal production. In: Biotechnology in the Feed Industry: Proceedings of Alltech’s 12th Annual Symposium (T.P. Lyons and K.A. Jacques, eds), Notthingham Press University, Nottingham, UK, pp. 249-259.

Kraiem K., J.E. Garrett, J.C. Meiske, R.D. Goodrich and G.C. Marten. 1990. Influence of method of forage preservation on fiber and protein digestion in cattle given lucerne, birdsfoot trefoil and sainfoin. Animal Production 50:221-230.

Mansbridge, R.J. and J.S. Blake. 1998. The effect of feeding different protein sources on intake, milk yield, milk composition and liveweight in high yielding Holstein cows. Proc. Br. Soc. Anim. Prod. p. 202.

Milford, G.F.J. and I.F. Shield. 1996. The potential of lupins for UK agriculture. J. Royal Agric. Soc. England 157:84-91.

MLC Beefplan. 1999 Meat Livestock Commission Uk Booklet, Milton Keynes, England. Moss, A.R. and H.F. Grundy. 1996. Lupins: The energy and protein value for ruminants and an evaluation as a protein source for young beef cattle. Occ. Symp. 30, Br. Grassld Soc., pp. 217- 220.

NIAB. 1997. NIAB Recommended Lists of Grasses and Herbage Legumes. NIAB, Cambridge, UK Scollan, N.D., A. Cooper, P.A. Evans and E.L. Jones. 2000. Enhancing the quality of beef by use of traditional breeds reared on low input, extensive and sustainable forage systems. J. of Hereford Cattle Society.

Waghorn, G.C., A. John, W.T. Jones and I.D. Shelton. 1987. Nutritive value of Lotus corniculatus l. Containing low and medium concentrations of condensed tannins for sheep. Proc. of the New Zealand Soc. of Anim. Prod. 47:25-30.

Winters, A., R. Fychan, D.R. Davies, J. Lloyd, R.J. Merry and R. Jones. 1999. Protein content of a range of ensiled legumes. Proceedings of the 12th International Silage Conference (T. Pauly, ed), Uppsala, Sweden, p. 170.

Author: RAYMOND JONES
Forage Conservation and Utilisation, Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion, Wales, UK
Related topics
Join to be able to comment.
Once you join Engormix, you will be able to participate in all content and forums.
* Required information
Would you like to discuss another topic? Create a new post to engage with experts in the community.
Create a post
Join Engormix and be part of the largest agribusiness social network in the world.
LoginRegister