Milk producers could be losing out to the tune of £60/cow by not paying sufficient attention to the rumen fill of their dry cows.

According to recent analyses by Rugeley-based Premier Nutrition, the relatively new yardstick of rumen fill as a measure of dry cow well being can be used as a powerful predictor of production post-calving and the likely metabolic disorders that could beset those fresh cows.

The theory is that rumen fill is thought to reflect the degree of rumen stability and its readiness to cope with the much larger workload and throughput demands once milk production starts in earnest.

“Poor dry cow rumen fill is costing at least 0.75ppl for our average TMS (Transition Management System) herd, or £16,000, and that’s through not allowing dry cows to have an acceptable rumen fill,” said ruminant director Dr Andrew Pine.

“Poor dry cow rumen fill is linked to milk and milk solid yields along with an increased risk of metabolic problems,” he claimed.

Describing the transition period as that of the last month of pregnancy and the first month of milk production, Dr Pine said that TMS has indicated that a colossal 84% of transition cows will experience some form of issue, and more attention needed to be paid to setting cows up properly during the dry period.

So what is rumen fill? It refers to the triangular area on the left hand between the hooks and short ribs and is essentially a measure of how depressed that area is on a scale of 1 to 5, with 1 being empty and 5 full.

The target is that a dry cow should have a rumen fill of 4 and fewer than 10% of the dry cow group should have a rumen fill of less than 3. Fresh cows should have a score of 3.

Premier’s analysis showed that the lower the rumen fill in the dry cows the higher the metabolic disease incidence post partum with levels of milk fever, RFM and metritis all declining as dry cow score increases.

In particular a rumen fill of less than 3 was linked to incidences of RFM 2.8 times more frequent, milk fever 2.3x, LDA 4.2x, mastitis 1.7x and acidosis 3x more likely in the fresh cows.

“By encouraging or allowing cows to have poor rumen fill in the dry period we are almost predisposing these animals to a huge increase in metabolic challenge,” maintained Dr Pine.

The analysis showed that a dry cow rumen fill score of 4 was linked to cows giving over 40kg, whereas for a RF of 2 or less this figure went down to 37.9kg.

“A poor rumen fill pre-calving can produce a 4kg milk loss after calving – this means we should be looking at the rumen fill in our cows on a daily basis and trying to maximize it wherever we can.”

This was carried through to proteins with poor RF dry cows having lower proteins – for example cows with a RF of 1 in the dry period showed 3.12%P post partum and a RF of 5 showed 3.25%. Similarly for fat + protein (F+P), with RF 1 dry cows showed just short of 2.7kg while RF 5 cows doing 3.1kg/day.

Referring to their newly launched 1000kg club which encourages members to reach 1000kg solids per lactation, he said: “Having poor rumen fill is really driving production down and this will be important if you want to encourage cows to join the 1000kg club.”

So what is causing this poor rumen fill? He explained: “With TMR transition diets it is a question of whether it is available in sufficient quantity or pushed-up enough, is it being properly mixed or are we getting sorting, or have we got ingredients in there that may go off creating palatability issues?

“Or is it purely a practical indication that on farm people are paying less attention to detail and there is a lack of recognition that we need to be driving rumen fill as high as possible?

“Or are we being driven to reduce the input to our transition cows to avoid ‘steaming up’ and the likely impact on body condition change?”

He said there was a pretty good correlation between rumen fill in the dry period and post calving and that if the dry cow RF was 2 i.e.  below target, then fresh cows were looking at fill figures of only 2.6.

Chronic lameness also had an impact on rumen fill as would be expected, and particularly so with heifers which intrinsically had higher rumen fill scores than cows.

“With dry cows the rumen fill came down from 3.50 to nearer 2.90 and for heifers it was more like from 4 to 3. Lameness is a real problem for achieving rumen fill in our cows.

“The effect of lameness on rumen fill in the dry cows has a considerable carryover to the rumen fill of the fresh cow,” he said.

Indeed the effect of lameness in the dry period, even though it may be corrected by the time the animal starts lactation, still had its effect.

“The animal that has correct rumen fill as a dry cow and as a fresh cow would have a rumen fill of around 3.1, whereas one that is lame in the dry period and correct in the fresh period the rumen fill was only 2.8.”

He went on: “If you have more than 10% of dry cows with a rumen fill of less than 3, then review group nutrition, establish an individual cow watch list, and use technology to act as a sort of sticking plaster on the problem.”