Maintain calving intervals throughout the year or risk losing cash

Producers who let higher-yielding cows have an extended calving interval are reducing their annual income from milk sold a cow, even when 305-day yields are rising.

MDC extension officer Tony Jackson believes too many producers are losing money because they only look at their milk recording figures. “I met one producer who thought he was producing 10,000kg in his 305-day yield, but was actually producing 8000kg.

“Because calving interval slipped from 385 days to 430 days, the milk sold was less than 8000kg a cow. And at a basic 18p/litre, the milk loss alone was £360 a cow a year.”

While it is good to set targets, using a 305-day lactation figure as a goal is misleading, agrees vet Peter Orpin of The Park Veterinary Group, Leicestershire. “People get hooked up on 305-day yields and don’t realise what is happening to annual milk sales. Yet you get paid on milk sold, but end up with the input costs of a 9000kg cow and the milk output of a 7500kg cow.

“In a perfect herd, the figures should be the same – with a 365-day calving interval. But what often happens is that a herd runs out of calvings and peak yields contributing to the herd average. It ends up with more stale cows in milk at any one time. As a result, overall milk sales fall.”

Mr Orpin believes cows should be managed to get back in calf as soon as possible after calving and recommends producers work with their vet to identify fertility problems. The 100-day in-calf rate – the number of cows pregnant 100 days after calving – and conception rate are good indicators. “Herds with 100-day rates over 45% produced milk a cow a year figures within 5% of the 305-day yield. When 100-day rates were below 30%, herds sold 10% less milk a cow a year.”

To get cows pregnant early, they must be fit and healthy. A good heat detection policy is vital as is starting to serve early.

“As long as the uterus is healthy, cows are sound and energy status is good, start serving 50 days after calving,” Mr Orpin recommends.

Getting the energy status right in early lactation is certainly paying off for Mr Orpin’s client Nick Wells, who runs Bill Wright’s 365-cow flying herd at Brookfield Farm, near Leicester. Despite a recent steep rise in milk output, fertility performance has actually improved. This is down to supplying enough energy to early lactation cows in the form of crimped maize, says Mr Wells.

“Crimped maize supplies 14MJ ME, instead of the 11MJ ME you get with rolled wheat. For the past six months, we’ve been getting at least six more cows to calve every month compared with the same period last year. And blood testing has shown cows are not energy deficient 7-21 days after calving.”

The herd’s 305-day lactation average is 9830kg, with a calving interval of 380 days and 100-day rate of 60%. “When you sit down and cost it out, milk sold a cow a year is important. We are a year-round calving herd, it’s what our milk buyer wants. But we want more cows in their first 100 days of lactation contributing to the bulk tank.”

Crimped maize is also included in dry cow diets far-off cows are offered 20kg a cow of the milking ration, then filled up with straw. Three weeks before calving, they move on to an ad-lib milking ration. Although only one milking ration is fed, Mr Wells runs two groups of milking cows.

The first contains fresh calvers and those being served. Cows are tail-painted weekly and vet visits are fortnightly. Once a cow is PD’d in-calf, she moves into group two. As cows are dried off from group two, they are replaced by more pregnant cows out of group one. “This keeps group numbers consistent and means we can concentrate heat detection just on group one.”

Inadequate heat detection and nutrition that has not kept pace with breeding are the reasons why many herds are now losing out on milk sales, adds Mr Jackson. “Too often, diets supply enough energy to produce milk, but not successfully get cows back in-calf as well.”

However, Mr Jackson says producers can make a start to recoup some of that lost income by joining their local MDC Dairy Business Group*. This allows them to benchmark their herd’s fertility using real farm data from other members.

*Benchmark your herd’s fertility against actual data by joining an MDC Dairy Business Group. Tel: 01285 646 500 for one in your area.

milk sold a cow a year

 Milk sold less than 305-day yield

 Extended calving interval

 More stale cows

 Fewer high yielding cows

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