Willie John Kehoe runs both a farming and contracting enterprise based near Foulksmills in Co Wexford. Each year after the winter crop harvest, he sows cover crops on his land for rejuvenation purposes. However, with the pressing issue surrounding the shortage of fodder in his local area, Willie John decided to zero graze the brassica crop and distribute it to local dairy farmers that had fodder deficits. He sowed a total of 45 acres of brassica crops, mainly Redstart and Rampart.

Zero-grazing machine issues

As for many people around the country, this was Willie John’s first year attempting to zero-graze brassica crops. Initially, he tried using a purpose built zero-grazing machine. The machine cut the crop well using the drum mowers. However, an issue arose regarding stones. Although Willie John explained that they rolled the ground twice, stones were still managing to find there way into the machine. Due to the lighter build of the zero-grazing machine, Willie John was afraid he might damage it.

Another issue with zero-grazing arose when transferring the crop to the storage part of the unit when the moisture levels were high. The zero-grazing machine uses a comb conveyor system to transfer the crop. This comb conveyer is equipped with forks. These forks were mulching the crop and as a result were blocking the conveyer unit.

Willie John Kehoe (contractor) and Paul Gannon (driver).

Mower and wagon

It was back to the drawing board for Willie John who then decided to try using a front mounted mower and one of his trailed forage wagons to cut and pick-up the crop.

The conditioner on the mower was breaking the leaves off the stem and mulching the crop. As a result the pickup reel on the forage wagon was unable to gather all of the crop. To overcome this, he removed the conditioner from the mower.

The design of the bed meant that the two outer hubs on each side of the mower rotated clockwise towards the centre of the mower. This directed the crop flow towards the centre of the mower, which left a nice swarth that the Strautmann Giga Vitesse II forage wagon was capable of picking up. Depending on the design of the bed, this may or may not be possible with other mowers.

From the forage wagon side of things, the only issue picking up the crop was that if the knives were left in they would mulch the crop. By dropping the knives and removing the conditioner on the front mounted mower, Willie John was able to cut and gather the crop at his ease.

The machine driver Paul Gannon explained that they only ever fill the wagon up to two thirds of its holding capacity. He noted, “This is because the brassica crops are a very heavy material with a high moisture content. By overloading the wagon it would mulch the material and possibly strain the panels. In addition, the land is beginning to get wet so two thirds of a load is plenty”.

Unloading the Strautmann forage wagon in a dairy farmers yard.

The crop

Willie John sowed a total of 45 acres of brassica crops on his own land this year. This is being sold by the tonne to local farmers, plus the cost of the machinery hire is separate.

Each tonne of fresh weight feed is costing the farmer €14 delivered to his/her yard. The majority of this feed was sold within a 10km radius. In addition, the hire of the machinery is €120 plus VAT per hour (tractor and driver, mower and forage wagon). Aside from his own brassica crops, Willie John has zero-grazed in excess of 200 acres on hire within a radius of 15km from his yard.

Willie John explained that the crop is yielding a fresh weight somewhere in the region of 10t/acre. Typically, each load from the wagon contains 12-15t of fresh weight. The weight and correct tonnage of each load is verified using a weigh bridge in Willie John’s yard. The gross weight of the three machines together and the load of brassicas amounts to 32t.

Willie John hopes to be out working on the land for another week or two. However, he explained that depending on how the storm pans out, the land may soon be too wet to travel on.

Nutritional advice for feeding brassicas

The zero-grazing of brassica crops is a relatively new phenomenon in Ireland. However, from a dietary point of view, zero-grazed brassicas should be treated in the same way as when cattle are grazing the crop outdoors.

Animals should be introduced to brassica crops slowly, over the space of a week- to -ten days.

Why regulate the crop?

Brassicas are rapidly digestible (80-90%). As a result, large intakes may lead to a risk of acidosis or bloat.

With this in mind, animals need to be introduced to brassicas slowly in order for the rumen microflora to adapt. When feeding the crop through a diet feeder, the inclusion rate of brassica crops in the diet should be gradually built up. Because the crop is so rapidly digestible, it’s essential that a source of fibre such as silage, hay or straw should be available at all times. Fibre will help reduce the incidence of acidosis by stabilizing the gut function. It will also slow down the rate of digestion leading to a further utilization and absorption of nutrients.

When the animals are getting accustomed to the crop, two thirds of the diet should include a fibre source such as silage or hay and only one third provided by the brassica crop.

However, when the animals have become fully adjusted to the brassica crop, one third of their diet (on a dry matter basis) should be from a long fibre source.