The main objectives were:
to extensify beef production and obtain more of the total production from grazed grass;
to reduce or eliminate use of fertilizer nitrogen and substitute clover or organic manure;
to measure nitrate nitrogen leaching to soil water in grassland grazed by beef cattle;
to determine the effects of extensification on carcass composition and on chemical, physical and sensory properties of beef.
Eighty hectares of grassland, 78 male beef cattle, 90 beef heifers and 60 beef suckler cows were devoted to the project throughout its 3-year duration. Fertilizer nitrogen level ranged from 0 to more than 200 kg/ha and fertilizer nitrogen substitutes were organic manure and various proportions of clover in the sward. Male cattle were produced in intensive, conventional and extensive systems and the beef suckler cows were managed in either conventional or extensive systems. Reducing fertilizer nitrogen from 220 to 57 kg/ha reduced herbage production by 18% but had little effect on composition or nutritive value or individual animal performance. The reduction in animal output per ha due to lower fertilizer nitrogen paralleled the reduction in herbage production. When swards with different initial proportions of clover were grazed by beef cattle, the clover proportions converged to a stable proportion of about 20%. Unimproved, unfertilized (except for organic manure) swards supported two-thirds the carrying capacity per ha of conventionally fertilized swards. Nitrate nitrogen concentration in ground water was generally low and well below EU limits on an annual basis. Mean daily gains for the intensive, conventional and extensive treatments were 1180, 833 and 700 g. Carcass output per ha ranged from 451 kg to 1536 kg. The intensive system carcasses (bulls) had better conformation, a lower fat score, more muscle and less bone than the carcasses from the other two systems. The intensive and extensive system carcasses had similar proportions of fat but the extensive system carcasses had more bone and less muscle. Neither fertilizer nitrogen level nor production system had any significant effect on meat quality.
Modern intensive grassland-based beef systems carry about two beef cows or produce more than 800 kg of beef carcase with inputs of more than 300 kg N fertiliser and 3 000 kg concentrates per hectare. About half the total system area is cut twice for silage which can produce a large quantity of highly toxic silage effluent. The new interest in the Community is in less intensive systems and on extensification of been production. Indeed some consumers believe that meat from less intensively produced cattle has higher quality and acceptability.
The project will examine the extensification of been production by providing more land per animal and more of the total feed nutrients from grazed grass. A further objective is to reduce inputs especially N-fertiliser and concentrates, input costs and risks of damage to the environment. This will be attempted by reducing fertilizer usage and decreasing silage effluent and slurry production. Effects of extensification on carcase and meat quality will be assessed.
The experiments include beef systems with different intensities of production :
< 60 to > 300 kg N-fertiliser/ha
< 250 to > 8 700 kg concentrates
0 to 100 M of area cut for silage
< 600 to > 2 100 kg/hectare of carcase output
Funding Schemeundefined - undefined
SY23 3EB Aberystwyth