Beef special: Focusing on fertility can boost your bottom line

“BCS is an indication of energy reserves, which is key as energy is the primary nutrient regulating reproduction,” she adds.

“Trials show that cows at BCS 1-1.5 at calving had on average a 440-day longer calving interval than cows at BCS 2.5-3.

“Low energy in late pregnancy will reduce subsequent fertility, so look to calve cows down at BCS 2.5 in spring.

“Condition score cows after calving and adjust feeding of thin cows accordingly. For example, a cow calving down half a condition score below target will need an extra 28MJ/day, compared to those in target condition, to ensure target BCS is achieved in time for bulling.”

Ms Drury also stresses the importance of minerals in reproductive performance with phosphorus, selenium, copper, cobalt, iodine, zinc and copper all essential for good fertility.

She advises having diets checked for mineral status and to supplement with highly bioavailable minerals as required.

Worryingly, she says new research indicates that copper deficiency is a significant issue in suckler cows.

She adds that this is the reverse to the situation with dairy cows where copper toxicity is a concern.

“A recent study from the University of Nottingham reported that 54.6 per cent of beef cows were found to be copper deficient, with 35.7 per cent of bulls sampled also deficient,” she says.

“These low levels are thought to be due to less frequent supplementation of suckler cows and the more extensive systems in which they are managed and indicates a potential problem.

Antagonist

“Furthermore, molybdenum is a well-known antagonist of copper and, over the years, its levels within forages has been increasing. Paradoxically the problem may only get worse thanks to efforts being made to improve grassland.

“Actions such as liming and increasing the proportion of high sugar grass species are resulting in reduced copper uptake and increase molybdenum within plants, so I would recommend all suckler producers to take a close look at copper levels in the diet”.

She also stresses the importance of ensuring bulls are fit and ready. It is suggested by Teagasc that 5 per cent of stock bulls are completely infertile, while as much as a further 25 per cent are sub fertile.

“A fully fertile bull running with 40-50 cows should successfully serve at least 94 per cent of cows in a nine-week period,” she says.

“However, a sub-fertile bull will only manage about 80 per cent, leading to an extended calving period, fewer calves born and more empty cows.”

Ms Drury advises bulls should be at condition score three eight weeks before the start of the breeding season.

She recommends all bulls should undergo a pre-breeding veterinary examination.

As trace elements including selenium, zinc, and copper, as well as vitamins A and E, are essential for sperm quantity and the production of sex hormones, she advises diets are carefully supplemented.

“You have one window to get the largest proportion of cows in-calf and this window will determine herd profitability,” she says.

“Paying attention to BCS, mineral nutrition and bull fertility now should be a priority to ensure improved fertility.”