By Lorna MacPherson, senior consultant SRUC

Lying time in dairy herds is a good indicator of cow comfort. Cows are strongly motivated to rest and under optimal conditions will choose to lie down for 12-14 hours a day.

Several studies have shown that if cows are deprived of resting time, they will compensate with less eating and socialising time and more resting time once restrictions are lifted. On average, cows will give up 1 minute of eating time for every 3.5 minutes of lost rest. This can lead to “slug feeding behaviour” which can have consequences for rumen function and feed conversion efficiency.

When a cow is lying down there is 30% more blood circulating through the udder compared to when she is standing up. The cow is also ruminating when she is lying down and this is why increased lying time tends to lead to an increase in milk production, with on average an extra kg of milk being produced for every extra hour of lying time.

Lying also takes weight off the feet, keeping them cleaner and allows them to dry off, reducing the risk of lameness, both in terms of infectious conditions like digital dermatitis, as well as solar haemorrhages and ulcers.

A cow will lie down and rise about 16 times a day, so anything that prohibits or discourages lying down (such as inappropriate cubicle dimensions or a hard lying surface) will reduce milk production.

Lying time will also be dependent on time away from cubicles for milking and other management factors such as vet checks, AI etc. The goal should be for cows to be away from the housing/feeding area for less than 3.5 hours a day. Unless you have an automated system that records lying time, how do you know how long your cows are lying for or whether cow comfort is adequate?

Cow comfort can be assessed in a number of ways, with the following signs indicating potential problems with cubicle dimensions and lying surface:

• Hock damage including abrasions, swelling and infection. Swollen hocks indicate that the lying surface is too hard, whereas hock rubs/hair loss suggests that the bedding (or lying surface) is too abrasive. Ideally less than 10% of cows should have hock damage.

• Cows rising abnormally (front end first).

• A high incidence of solar ulcers in the herd (not nutritionally related).

• Increased mobility problems during the housed winter months.

• Cubicle Comfort Index. This is an indicator of how willing cows are to lie in the cubicles. Out of all the cows in contact with the cubicles (either lying, standing or perching), at least 85% should be lying down. The best time to assess this is two hours before milking.

• If cows take longer than five minutes to lie down in cubicles look for reasons why they do not lie down immediately.

• Cows perching in cubicles with their rear feet in the passageway are more prone to claw horn diseases as well as mastitis, due to greater contamination of the udder, teats, legs and tail. There should be less than 5% of cows perching and a higher incidence can indicate wrong positioning of the neck rail.

The following two tests can be used to assess cubicle comfort:

• Knuckle test – make a fist and rub your knuckles firmly across the cubicle bedding. If it is uncomfortable and results in rubbed/scraped skin, it will also be uncomfortable for the cow’s skin, making her less likely to lie down.

• Knee drop test – drop to your knees from a standing position onto the bedding surface of the cubicle. If it hurts your knees, it will also hurt the cows! Bear in mind that when a cow lies down, approximately two thirds of her weight goes onto her front knees, which drop from a height of 20-30cm. Your knees should also be dry. If wet, then conditions are more favourable for bacterial growth and the higher the risk of environmental mastitis.

A recent study of lying time in six dairy herds in the south-west of Scotland using the Cow Alert System from Ice Robotics showed that some herds were achieving only 10-11 hours of lying time, even when time away for each of the two milkings was no more than one hour. Two of the farms that recently invested in mattress upgrades, noted that they gained in the region of 1.3 to 2 hours extra lying time a day with an uplift in daily milk production of up to two litres.