It pays to keep cows for longer (Nov/Dec 2021)

There is strong evidence to link an increased number of lactations with greater potential profitability. So says Trouw Nutrition GB’s ruminant technical manager Mark Hall.


A recent study, carried out by University of Florida, modelled the optimum number of lactations needed to maximise profitability per cow, taking into account a number of factors. It concluded that profitability is maximised by achieving between five and 5.5 lactations per cow,” Mark Hall says. “The cost of producing heifers, which is an investment that has to be recovered during the productive life of the cow, was included in the study. The fewer the number of lactations, the greater the repayment cost per lactation.

“The work also took peak lactation yield into account. This increases in successive lactations up to lactation five, and then declines. So too many young or old cows in the milking herd brings a yield penalty,” says Mr Hall. The work also considers calf value and the opportunity to optimise beef calf value by reducing replacement rate. And, finally, it considered the gains in genetic improvement. “It is argued that if cows remain in the milking herd for ‘too long’, the genetic merit of the herd will increase more slowly. But, equally, if average lactation number is too low then the value of the genetics is not realised because animals leave the herd too soon. Genetic merit gain certainly does not justify reducing average lactation number,” adds Mr Hall. Figure 1 draws all these elements together and shows the potential financial losses against lactation number.

Figure 1: Potential financial losses against lactation number

It turns the difference in yield per lactation (lack of maturity in young cows, aged-cow cost in older cows), lost chance for beef calves (calf-value opportunity cost) and the impact on genetic progress (genetic opportunity cost) into costs to assess the total cost for different numbers of lactations.

Optimum profitability

“It shows the minimum potential financial loss, which equates to optimum profitability, if cows remain healthy, is achieved at around 4.5 to five lactations, suggesting dairy businesses will see a positive impact on profitability by working towards this,” says Mr Hall.

“If producers invest time in assessing the required number of lactations to optimise profitability per cow the result, in most herds, will be an increase in the average number of lactations per cow. Our Healthy Life programme is about identifying how to increase lactation number to drive profitability. And our survey has indicated the scale of the opportunity.”

More than 100 producers completed the survey, run in conjunction with CowManagement, which was designed to highlight where producers should focus their efforts to improve lifetime profitability. The respondents were typically milking around 200 cows, averaging 9,100 litres on a twice-a-day milking, on all-year-round calving systems. But a cross-section of business sizes and systems is represented in the results.

The average lactation number in the sample was 3.9 per cow, suggesting these herds could make a significant impression on profitability by developing strategies to increase the number of lactations per cow. One in 10 of the herds were averaging fewer than three lactations, suggesting a great opportunity. And 90% of respondents acknowledged the optimum number of lactations was between 4.5 and 5, so there was an appreciation that improvements could be made.

Lifetime daily yield (LDY) spreads a cow’s production across her whole life, from birth until the day she leaves the herd. Research suggests the break-even level for cows completing the optimum number of lactations is 14 litres per day. “For optimal profitability we are looking for cows that calve in younger, persist in the herd and produce well,” says Mr Hall. “The more producers can reduce cows’ non-productive days by getting them back in calf, efficiently, the better.

Two thirds of respondents did not know the average LDY figure for their herd, while 30% of those who did know said it was less than 13 litres. This suggests a combination of extended age at first calving and shorter productive lifespans. “By calculating the figure for your herd you can target where to focus management to improve.”

The average producer in the survey had 22% heifers in the herd but more than 30% of respondents had in excess of 25% heifers. “Improving the number of lactations per cow, and therefore reducing culling rate, not only improves profit per cow but also reduces heifer rearing costs,” says Mr Hall. “With farms requiring fewer replacements year on year, this also further reduces the carbon footprint of the dairy business.”

Herd longevity

While accepting the problems with bTB in specific areas, the main reasons for animals leaving the herd are typically failure to get back in calf, mastitis and lameness. “It’s a picture that’s been the same for many years,” he says. “Developing protocols to improve these areas, including looking closely at transition-cow management, could have a significant impact on herd longevity.

“The survey has certainly helped to confirm there is scope to increase average lactations per cow in UK dairy herds, which will help maintain profitability while making a significant contribution to carbon reductions,” says Mr Hall. “I would urge producers to invest time in assessing the situation on their units and developing management protocols to improve performance. Don’t be blinkered when assessing your current status. Be honest and challenge yourself.”

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