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Shall we have a hospital pen for lame cows?

Peng Ji Published on 31 December 2012

Lameness is one of a few words that incessantly irritates the nerves of most Canadian dairy farmers. The highest lameness incidence usually occurs in early lactation. Besides the potential loss of milk, lame cows usually have poor reproduction performance and account for a big share of involuntary culling cases.

Foot problems were reported to contribute 88 percent of all lameness cases. Sole ulcers and white line lesions are the most common claw lesions on North American dairy farms.

Improving floor and bedding conditions and timely trimming is undoubtedly helpful to decrease lameness. However, recent research from Cornell University showed evidence that these claw lesions may have originally developed from the inside out.

The digital cushion (DC), composed of mostly fat tissue, functions as an elastic shock absorber in the middle of the distal phalanx and the corium and pumps the blood up in the leg as the cow walks. As we know, high-producing cows use body fat to support milk production during early lactation.

A study using 501 lactating cows found the thickness of DC was positively associated with body condition score (BCS) and gradually decreased beginning the first month after calving and became the thinnest at 120 days of lactation.

Dr. Bicalho at Cornell University proposed that the fat layer of DC was also mobilized simultaneously, thus the compression of the phalanx on the corium may result in a claw lesion when DC is too thin to serve as a cushion.

The prevalence of sole ulcers and white line disease was highly associated with thickness of DC. In addition, older cows (two or more lactations) were more at risk to these claw diseases and had about 20 percent higher incidence of lameness than did first-calf heifers.

This explained why a lot of high-producing cows or underconditioned dry cows are more often the victims of lameness during lactation. Furthermore, these cows are less competitive at the feedbunk, which will quickly exacerbate the situation.

As reported in several studies, 3x milking can increase milk production by 20 percent compared with 2x. Hence, it’s quite logical that high-producing cows should lose less body condition in 2x vs. greater milking frequency.

A followup study from Dr. Bicalho’s lab investigated whether decreased milking frequency helped the recovery of lame cows. Five hundred lame cows (defined as locomotion score > 2; 1 is normal, 5 is extremely lame) were either allotted to 2x or 3x milking groups.

As expected, the 2x group restored BCS sooner than the 3x group and had 9 percent more cows recovered from lameness at 90 days of lactation.

However, it is very interesting that the milk yield of the entire lactation was not different between the two groups. The author explained the possible reason: All cows were defined as lame at the start of the study, so increased milking frequency may not improve lactation performance.

Moreover, serious consideration of the limitations of the study were given by the author – the 3x group was commingled with healthy cows in three pens, whereas all the cows in the 2x group were housed in the same pen.

It’s very likely that 3x lame cows are less competitive in the feedbunk, stall and parlour than their healthy herdmates (both 2x and 3x pens were 10 percent overstocked). So they may spend much more time standing in line, anxiously waiting for milking, food and beds than the 2x group, which worsens the lameness.

However, the commingling of 3x lame cows with healthy cows does reflect the typical situation on most farms. It is not hard to reach this question: What if we have a hospital pen for subclinical lame cows with a lower stocking density and milking frequency?  PD

—Excerpts from Miner Institute Farm Report, February 2012

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