The Greenmount Hill Farm Centre at Glenwherry in Co Antrim is home to 1,100 ewes and a herd of 100 suckler cows, with calves transferred at weaning to the lowland Beef and Sheep Centre at the Abbey Farm.

The aim of the Hill Farm Centre is to have efficient livestock that provide environmental benefits. The farm is managed under Countryside Management Scheme guidelines and is part of the Glenwherry Hills Regeneration Project.

The suckler herd on the farm was also set up to demonstrate the importance of hybrid vigour in livestock production, and is based on a three-breed rotation of Aberdeen Angus, Shorthorn and Limousin. During the summer, the herd runs three stock bulls, one of each breed, with a group of approximately 30 cows.

Each cow group gets its own grazing area which may be part of an Upland Breeding Wader Site. After weaning, cows are regrouped based on body condition, and fatter cows may return to a breeding wader site to help manage the habitat and also cow condition.

The herd operates a compact bulling and calving period with bulls running with the herd for three cycles. Cows are pregnancy diagnosed using ultrasound scanning 45 days after the bulls are removed, and any empty cows are slaughtered when adequate fat cover is reached.

Compact calving is a very effective way of maintaining a 365-day calving interval and, in theory, should provide a very even calf crop, as around 70% of the calves are born in the first three weeks of calving.

If all calves grew at the same rate, there should only be about 60kg to 70kg difference between the heaviest (oldest) and lightest (youngest) at weaning. However, that doesn’t allow for other factors, including the mothering ability of the cow. From top to bottom, the range in calf weight at weaning is around 150kg.

Despite the difficult conditions at Glenwherry and the poor summer of 2017, calf growth rate and cow body condition at weaning were both acceptable. We are aiming for a 600kg to 650kg cow that weans 50% of her body weight at 200 days of age.

As shown in Tables 1 and 2, across the three main groups of cows, average results are slightly below this target. The Shorthorn cows crossed to the Angus produced the highest weaning efficiency, at 47.9%, but not the heaviest calves.

The Shorthorn calves out of the Limousin cows were ahead in terms of weight, but because the Limousin cows are heavier, their weaning efficiency was behind that of the Shorthorn. It highlights the point that cow weight is one of the main drivers of weaning efficiency.

This is also shown in Table 2, where the 10 cows with the lowest weaning efficiency averaged 733kg at weaning time. In a hill environment, these heavier cows must work harder to maintain themselves, which invariably has a negative effect on the amount of milk provided to calves. The aim must be to keep mature cow size under control.

One tool that is currently missing from the toolbox to help us do this is the absence of a mature cow weight estimated breeding value (EBV). It is currently technically available, but so few breeders submit cow weights that it is virtually impossible in many breeds to find a bull that will produce fast growing progeny, without increasing mature cow weight.

Grouped

After weaning, cows are grouped by body condition score. The fattest cows are fed a restricted amount of the poorest silage on the farm. At present, daily intake is 33kg. Average-condition cows are currently eating approximately 47kg of fresh silage with a dry matter content of 26.1%, crude protein content of 9.3% and an ME content of 10.1MJ/kg.

The thinnest group (which contains older cows and first-calving heifers) are currently being fed this silage plus 1kg concentrate to gradually increase their body condition. These cows will be condition scored again next month and concentrate feeding will be reviewed then.

Health

The herd is in the AFBI cattle health scheme and is due a Johne’s test shortly. Cows will be vaccinated for IBR, BVD, leptospirosis and scour in February prior to calving. Previous blood testing has identified low levels of iodine and selenium, so cows are given a mineral bolus at turnout and also again at housing.

Cows were treated for fluke six weeks after housing. Based on an increase in worm burdens in lambs at the Hill Farm Centre, and experience from the local veterinary practice, cows have also been treated for lungworm this year on veterinary advice.

A small batch of Shorthorn heifers born in April 2016, that were not deemed suitable as replacements, were slaughtered in December for the Glenarm Shorthorn Beef Scheme. It comes with an attractive bonus of 10% above quoted U3 beef price.

Cattle for this scheme should be between 280kg and 380kg carcase weight, and require a greater fat cover than that for conventional markets. Carcase weight was 305kg at an average age of 19.6 months, graded R-4=, and achieved a bonus of over £120/head.

The remainder of the 2016 calf crop will be marketed through another two outlets, namely Aberdeen Angus Quality Beef Scheme for Aberdeen Angus cattle, and ABP for Limousin cattle as they reach market specification.