Cost and performance of livestock grazing brassica and forage crops

See comparisons of livestock growth performance and costs when grazing brassica or forage crops. 

The quality of your crop and silage, crop type, and yield will impact allocation and feed budgeting and, therefore, costs.

Some considerations:

• Feed costs can be 20–30% lower than that of housed animals
• Heifer rearing costs can be reduced by 50–64% (£150–178/heifer) through outwintering, with 80% of this saving from capital/building costs
• Potential lower requirement for conserved forage, bought-in feed, and muck storage and disposal compared with housing
• Investment in infrastructures such as handling facilities, water troughs, ring feeders, and fencing may be required
• Labour will be required to measure forage crop yield and move fences; additional labour may be required, depending on your system

Forage crop production and costs

Notes: Drilling methods are indicated as follows ¹precision sown, ²drilled and ³broadcast. *Take care when sowing early as this is a vigorous crop and, if not grazed, will bolt. **Variable cost of growing includes cultivation, seedbed preparation, seed, fertiliser and sprays (SAC, The Farm Management Handbook 2015/16).

Stocking and cost guidelines

Assumptions: 600 kg suckler cows. Dry suckler cows requiring 68 MJ ME/d. 350 kg growing cattle gaining 0.75 kg/d requiring 63 MJ ME/day. 70 kg ewe requiring 10 MJ ME/day. 30 kg lambs gaining 200 g/d requiring 13 MJ ME/day. *Variable costs of establishment (SAC, The Farm Management Handbook 2015/16) with predicted intake related to production, 70% utilisation and 70% of diet from forage crop. Costs of fibre source and labour are not included.

Find out how John manages forage crops to feed his dairy heifers and save on costs.

The success of the outwintering system for John Millington depends on having the right infrastructure in place before the start of the winter, including:

• Plentiful water troughs
• Fencing
• Concrete sleeper tracks
• Allocating feed well in advance

John uses stubble turnips for the first-year heifers and fodder beet for second-year heifers as part of a planned grassland reseed strategy.

“Stubble turnips yield 5–6 tonnes DM/ha but are not sown until mid-July, but fodder beet is a full season crop and yields 25 tonnes DM/ha.”

As a rule of thumb, John says he will grow an 8-acre (3.2 ha) paddock of stubble turnips for 100 year-one heifers: “As the acreage of roots changes, we adjust the number of bales to give 100 days of feed at the start of winter.”

John adds that: “The cost of rearing housed heifers on silage over winter is around £1.20 per day. However, this drops to 89p for winter rearing when the heifers are outwintered on roots.”

With around 100 heifers of each age group kept on this farm over a 100-day winter, this equates to a saving of £3,100 for each group of heifers.

“More important still is the improved health we have seen in the heifers, in particular, the absence of pneumonia,” says John. “If the winter gets bad, we will give the heifers access to hard standing on the concrete sleeper tracks, but this is rarely needed – perhaps once or twice a year.”

He concludes that: “It’s essential to give them your very best grass when they come off the stubble turnips for at least six to eight weeks leading up to service.  This ensures they achieve target mating weights and sets them up for good conception rates when service starts.”

Brassicas can be cheap sources of feed for holding or finishing store lambs and finishing cull ewes. Performance can be variable and will depend on crop yield and efficiency of use but has potential for growth rates up to 250 g per day.

Utilisation tends to be optimised when grazing pressure is high, and weather conditions are good, as soiling of crops leads to rejection.

Example: performance from grazed brassicas compared with concentrate finishing

Source: SAC Consulting. The Farm Management Handbook 2015/16

If you would like to order a hard copy of Using brassicas for Better Returns, please contact publications@ahdb.org.uk or call 0247 799 0069.