Herd thrives on diet of just whole-crop forage

1 March 2002

Herd thrives on diet of just whole-crop forage

Could dropping both grass and maize silage from dairy

cow rations improve herd profitability? Richard Allison

reports from a farm walk in the east midlands

ACHIEVING high milk yields from rations containing whole-crop silage as the sole forage without compromising cow health sounds impossible, but not for one producer.

John and Janet Platts abandoned grass and maize silage more than two years ago at Hazelmere Farm, Creswell, Derbys. "High quality grass silage was always difficult to produce on the 109ha (270 acres)," says Mr Platts.

"Second and third cut yields were often light because fields rapidly dried out during summer. Reasonable quantities were only achieved in wet years, but ensiling in wet weather meant quality was poor."

Mr Platts also found growing maize to be problematic. "Harvesting was often late and mud on roads was a constant concern. There were also problems with the public as kids used to play in the crop. But in contrast, cereals and peas can be easily grown on the unit."

Another reason for considering whole-crop was the average herd milk yield was limited to 5500-6000 litres when feeding grass silage. Mr Platts long-term aim is to increase milk output by improving forage quality, so fewer cows are needed, easing his workload.

However, many producers believe feeding whole-crop cereals leads to poorer milk yields, said Biotals John Bax. "Whole-crop silages were often fed incorrectly in the past due to a lack of understanding. There is no reason why 10,000 litres cannot be achieved from whole-crop based rations."

The decision to stop grass and maize silage production and adopt whole-crop as the sole forage component of the ration was made on the advice of Agriplan independent adviser Robin Winterhalder.

Last year, 23ha (56 acres) of winter barley and 8ha (19.5 acres) of a barley/pea bi-crop were grown and ensiled. "This provided 300t of forage dry matter, the calculated requirement for the herd."

Growing, harvesting and ensiling whole-crop seems such an easy way to make forage, says Mr Platts. "There is only one cut compared with three separate cuts for grass silage."

This winter, whole-crop silage accounted for more than 75% of the ration, says Mr Winterhalder. "Barley and the barley/pea bi-crop are fed in the ratio of 1:4 and balanced with a barley, soya and rapemeal blend to achieve an energy density of 11.9MJ/kg dry matter and a crude protein of 17%."

A molasses and urea product was also included at 1kg/day to stimulate feed intakes and provide extra rumen nitrogen. The result is that cows are eating more than 23kg dry matter and the 12-month rolling average is approaching 7500 litres, with nearly half from forage.

"Over the last two years, milk yields have improved by 1500 litres/cow and concentrate use fell by 400kg, resulting in a £218 improvement in margin over purchased feed," says Mr Winterhalder.

Despite cows consuming the equivalent of 11kg/day of cereals, Mr Platts reports no adverse effect on animal health and no cases of acidosis. "Fertility has remained good with a calving interval of 375 days and a conception rate to first service of 77%."

A further benefit of adopting a 100% whole-crop system is that lower dietary protein levels are needed, says Mr Winterhalder. "This is because protein from pea silage is of higher quality than protein in grass silage.

"Cereals require less fertiliser than grass or maize, which combined with lower protein rations makes this system attractive for producers facing nitrogen vulnerable zone restrictions."

Despite recent moves to harvest whole-crop cereals with forage harvesters fitted with forage mills to improve starch digestion, Mr Winterhalder believes this is inappropriate because it would lead to insufficient slowly digested starch in the ration. "At least 2-2.5kg/day is required.

"Instead, the barley was harvested at 53% dry matter, a little drier than the 50% target, using a conventional forage harvester. This higher dry matter was due to the rapid ripening of the crop. Growing wheat instead can help avoid this as it tends to ripen more slowly than barley."

With the barley/pea bi-crop, dry matters ranged 45-65% in different areas of the field. Mr Winterhalder advises growing a different pea variety next year to reduce crop variability.

This bi-crop was cut with a rape swather, wilted for 2-3 days and picked up with a self-propelled forager. "When ensiled, it was topped with a 5-6ft layer of brewers grains. This cuts down on storage requirement and saves time when mixing the ration."

In the first year, Mr Platts also grew and fed fodder beet with the whole-crop cereal. "But this was dropped in the second year as cows did not perform well and it created too much extra work. This is the last thing I want." &#42

No of cows 80

Average milk yield (litres) 7200

Milk from forage (litres) 3200

Milk fat (%) 4.05

Milk protein (%) 3.41

Concentrate use (kg/litre) 0.25

MOPF (£/cow) 1166

Inset left: John Platts says growing and ensiling whole-crop barley is a much easier way to make silage.

Inset right: Robin Winterhalder says cereals require less fertiliser than grass or maize, making whole-crop systems attractive in nitrogen vulnerable zones.

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