IT is widely accepted that calving dairy heifers at 24-26months of age is far from easy, however, the financial implications of failing to hit specific targets to calve at two-years of age to maximise genetic potential and lifetime yield, far outweigh the cost.

Speaking at Mole Valley Farmers' inaugural Scottish Calf Conference in Fenwick, technical manager, Tom Hough, told producers the average age at first calving in the UK is 28 days with feed accounting for a whopping 37%.

"Average feed costs vary from £1073 to £3070 with a mean average of £1819 per calf. Add to that the fact that approximately 14% of live-born heifer calves are fail to achieve first-calving, with a further 15% of milking heifers culled in their first lactation, and rearing calves becomes an extremely costly business especially when the number of days to pay back the cost of heifer rearing post calving is 530days," he said.

Instead, producers were encouraged to pay more attention to the nutritional needs of the dam.

“Calf health starts at the foetal stage by ensuring the dam has the correct nutritional diet,” said dairy consultant, Dr Bob Corbett, USA.

Dr Corbett who overseas more than 1m cows on his global rearing programme stressed the importance of the whole aspect of calf rearing through to first lactation. This included dry cow feeding and management throughout an animal's pregnancy in order to achieve healthy new born calves.

“Heifers have tremendous ability to utilise protein for increased growth rates and nutrition and management needs to change to allow the heifer to grow and achieve her genetic potential.”

During late-pregnancy foetal metabolic rate is twice that of the dam and glucose and lactate account for almost 60% of the metabolic fuel.

Hence he stressed the need to provide higher levels of protein and recommended a 25% protein feed. An easy goal is to double birthweight within eight weeks with an optimal goal to increase birthweight by 2.5 times within 10 weeks, he said.

Furthermore, Dr Corbett added that the influence of maternal nutrition on progeny health is also an important aspect of calf development. Poor nutrition of the dam results in reduced birthweights; increased morbidity and mortality in young calves as well as, an increase in respiratory diseases in calves at post weaning. Heifer calves should be born with adequate body condition.

“Thin calving-down heifers or cows result in thin new born calves that are weak and with little body-reserves. This is common when animals are reared on pasture-based systems without feed supplementation. This therefore slows down the early growth rates of the new born calf. It’s also important to ensure all calves receive adequate levels of colostrum.

“It’s important to have high quality colostrum available with calves receiving 10% of their bodyweight at first feeding and 5% at second feeding. Farmers should therefore use a Brix Refractometer to test colostrum quality. Calves have an amazing ability to fight disease if the immune system has the proper fuel. Management and hygiene is also extremely important and death loss is obtainable at 1% or below with proper management practice and nutrition.”

The effect of growth-rate and nutrient intake prior to weaning has a more significant effect on milk yield than genetic selection. According to Dr Corbett, pre-weaning calf nutrition and management can yield four to eight times more milk, than genetic selection per lactation.

Animals that suffer pneumonia or illness have subsequent reduced growth-rates and do not make up compensatory growth in later development. Calves that were treated with antibiotics produced approximately 500kg less milk in their first lactation, compared to animals without any record of treatment.

“When feeding for more nutrient supply above maintenance, we are setting up the calf to be a better lifetime milk producer. Herd life is primarily related to milk production and by implication we may enhance herd life through better early life nutrition,” Dr Corbett concluded.

Dr Alex Bach, department of ruminant production, IRTA, Spain, also stressed the importance of nourishing and managing young calves in order to maximise future milk production.

He said the most common objective is to have a Holstein heifer freshen at about 22-23 months of age, weigh 650kg and be 137 to 147 centimetres at the withers. However, the mean at first calving in the US is 27months and in Europe the age varies from 25-29 months depending on country.

"Over the past 40 years milk production has doubled per cow, while milk production per capita has decreased by 14%. However, on a global-basis, the world requires increased levels of milk production," he said.

“For rearing calves, the early stages of growth are extremely important and colostrum is the first line of immunity as well as, the first source of nutrients. The most common recommendation for calf feeding has been to offer starter feeds and not provide forage. However, recent evidence suggests offering chopped forage at 2cm in length may increase an animals total feed intake.”

Dr Bach stated that important savings could be achieved with adequate age at first calving being achieved and for farmers not to be afraid of rapid-growth during the pre-pubertal period. He recommended a minimum of 2kg per day of solid feed consumption by the end of weaning, and to incorporate a quality pelleted starter feed as well as, chopped straw to ensure rapid growth in early life.