16 February 1996

Good records are a measure of herd health

Poor dairy herd health and fertility is a huge drain on profit. Jessica Buss reports

POOR herd health and fertility management are costing an average of £160 a dairy cow. The main culprits are poor fertility management, mastitis and lameness.

This is the finding of Dr Dick Esslemont and Dr Mohammad Kossaibati in an RSPCA-funded study of 90 herds using DAISY records for the 12-month calving period between 1992-93.

The worst herd lost £315 a cow according to the new DAISY herd performance index (HPI), developed by Dr Kossaibati.

"Many producers fail to realise how much they are losing," says Dr Kossaibati. "Greatest loss is still poor fertility, with the average pregnancy rate at 46% when it should be nearer 55%. And the average heat detection rate of 55% indicates that cows are being submitted for service on a inefficient basis."

In fact pregnancy rates are slipping by 1% every three years.

Dr Kossaibati advises assessing cow fertility using the FERTEX index. This values each day below or above a 368-day calving interval at £3; failure-to-conceive culls above 5.3% at £770 each; and number of services a conception above 1.8 at £20/service. Average herds have a FERTEX index of £76/cow.

Infertility would be almost overcome if tail paint were used to aid heat detection, and if milk progesterone testing was used at the day of insemination and 19 and 24 days after insemination, he says.

However, even herds with good fertility performance are losing money through poor herd health.

"Each disease has a direct cost that includes the vets time, cost of treatment, herdsmans time and lost milk," he says. These direct costs are measured by the HELEX score. But there also indirect costs such as increased risk of culling or extended calving interval."

Vet advice needed

HEALEX is most influenced by the number of cases of mastitis and lameness. But it also includes the cost of calf mortality, aid at calving, retained foetal membranes, vulval discharge and oestrus not observed.

"Every herd is losing from these diseases but the bottom 25% are losing most at £110 a cow and this reflects poor herd management, highlighting the need for effective vet advice," he says.

Mastitis is the most expensive disease, accounting for 38% of the average herds HEALEX score, followed by lameness at 27%. The average herd loses £63 a cow due to these production diseases.

Reducing disease and fertility costs as measured by the HPI score doesnt depend on controlling all production diseases – just keeping fertility, mastitis and lameness under strict control, he stresses. But even the top 10% of herds have some room for improvement.

"Tackle disease as early as possible to control existing infections, prevent new cases and reduce the risk of other diseases," says Dr Kossaibati (see performance targets).

In terms of non-fertility culls, the top 25% of herds save £3 a cow, but the average herd is losing £20 a cow. Many of these culls may be sold for unknown reasons, he adds.

Dr Kossaibati advises that considering losses in terms of HEALEX will allow vets bills to be seen in a better light. "The vets bill including drugs is only a small proportion of the direct and therefore the total cost of disease," he says. He puts the figure at 50% of HEALEX and below 20% of HPI. Much of the cost of disease is in reduced milk yield, discarded milk and reduced fertility.

Tackling herd health must begin with full and accurate records for every disease, he claims. This would allow vets to monitor herd health status, devise a strategy to improve it, and to work with the producer to deliver that strategy on a cost-effective basis.

Priorities must be fertility, mastitis and lameness. The benefits from a well organised and planned herd health scheme outweigh the cost by at least five to one. &#42


&#8226 Twinning 2%.

&#8226 Calf mortality 5% (of calves born).

&#8226 Aid at calving 1%.

&#8226 Retained foetal membrane 1%.

&#8226 Milk fever 2%.

&#8226 Oestrus not observed 22%.

&#8226 Vulval discharge 6%.

&#8226 Mastitis 11.%

&#8226 Lameness 7%.

(% of herd affected)


FERTILITYTARGETS


&#8226 Serve at least 92% of cows that calve.

&#8226 AND have a calving to first service interval below 70 days.

&#8226 AND heat detection rate above 56%

&#8226 AND pregnancy rate above 47%


Cost of disease (£ a case)

TotalDirect

(HEALEX)

Mastitis183119

Lameness24693

Vulval discharge16271

Milk fever22059

Retained foetal

membrane29883

Calf mortality310142


HEALTHTARGETS


Cost of poor health and fertility (£/cow)

averagetopbottom

25%25%

FERTEX£76£36£122

Non-fertility

culls£20-£3£41

HEALEX£63£39£91

HPI£159£72£254


FERTEX measures fertility costs, HEALEX measures disease costs, and both, including non-fertility culls are combined in the herd performance index (HPI).

Poor heat detection rates show that cows are being submitted for service inefficiently. Producers should aim for heat detection rates above 56%.

Over the last three years average pregnancy rates gave slipped by 1%… Using tail paint to aid heat detection could help reverse that trend.