14 June 2002

Best combination is soya-rape and maize, not wheat

By Jessica Buss

INCLUDING wheat in a maize-based beef finishing diet is of no financial benefit, increasing production costs by £26/head.

Thats the result of a CEDAR/University of Reading study* using British Simmental x Holstein Friesian bulls from 125kg to a finishing weight of 620kg. The 48 bulls were split into four groups to assess two rearing diets up to 450kg and two finishing diets from 450-620kg (see table).

The best performance was achieved from bulls fed maize and a soya-rape mix in both the rearing and finishing stage, without either grass silage or wheat added, explains trial co-ordinator Steve Field.

Most of this benefit occurred in the finishing stage. Although bulls ate less when fed just maize and protein concentrate (diet three), they grew marginally faster.

"Animals fed diet three were better at converting feed than those supplemented with wheat," explains Mr Field. Diet three saved feed and reduced production costs by 20p/kg gain for animals fed diet one in the rearing phase and 15p/kg for those fed diet two. Forages were costed using actual university farm data where possible and cracked wheat cost £80/t.

Feeding maize as the sole forage in the rearing phase also resulted in better feed conversion than the alternative diet including grass silage. But the real benefit was the improvement in daily liveweight gain, which was 1.53kg and 1.44kg, respectively.

"This meant maize only-fed rearers spent 13 days less reaching the target weight of 450kg than those on the diet including grass silage," says Mr Field.

This benefit was seen in reduced days to reach the target slaughter weight at the end of the trial. Those fed grass silage in the rearing phase finished at 341 days and 334 days for diets without and with wheat, respectively.

Although those fed no grass silage followed by maize without wheat finished in 325 days, costs of production were less than for diet one then wheat-fed animals – which finished in the shortest time of 316 days.

All bulls finished with an acceptable R grade for conformation and at fat class 4L, except those on diet two followed by four which were fat class 3. But by the chosen finishing weight of 650kg for the study bulls were becoming difficult to handle, he warns.

Mr Field is now repeating the same study using Simmental cross steers and heifers.

&#8226 The trial was sponsored by DEFRA and industry sponsors, including MLC, ABN, MGA and the British Simmental Society. &#42

Bull maize feeding trial results (from 125kg)

Rearing diet one one two two

Finishing diet three four three four

Dry matter intake (kg) 6.64 7.13 6.81 6.87

Daily weight gain (kg) 1.5 1.54 1.43 1.46

Feed conversion (kg feed/kg gain) 4.42 4.63 4.79 4.72

Days 125kg-620kg 325 316 341 334

Variable cost p/kg gain 43 48 44 48

Variable cost £/head 209 235 216 232

Bull beef diets (% dry matter)*

Rearing phase

Diet one 83% Maize 17% Soya/rape

Diet two 55% Maize 27% Grass silage** 17% Soya/rape

Finishing phase

Diet three 83% Maize 17% Soya/rape

Diet four 62% Maize 21% Soda wheat 17% Soya/rape

* Diets fed as total mixed rations. ** Average quality grass silage.