Behavior
The Association of Stress to Lameness
It is known that stress affects reproductive efficiency, the working of the rumen, milk production and immune function (Grandin, 1997).
Factors which cause Stress
Aggression
In the natural order of things, some cows are more aggressive than others.
When one animal invades the "personal space" of another, the least dominant animal is stressed sufficiently to modify its behavior.
In the increasingly confined space of the modern dairy operation, "social confrontation" is often problematic.
In one study it was found that aggression in housed cows was four times greater than animals at pasture (Galindo and Broom, 1994). Attention to building design will minimize this problem.
Differences in behavior of cows at pasture and housed animals are highly significant (Wierenga 1986; O'Connell et al 1989; Miller and Wood-Gush 1991; Krohn & Munksgaard 1993).
Insufficient Space
The least tame animals will require the most space or greatest "flight zone."
Heifers are particularly sensitive until they become "socially integrated."
Alleyways and spaces of maximum cattle traffic should be particularly spacious.
In the photograph below two cows would have insufficient space to pass between the cow lying down and the one standing in the stall.
Noise
Cows are more sensitive than people to high frequency noises (Ames and Arehart, 1972). The sound of the human voice is more alarming for cattle than other sounds (Waynert, et al, 1999).
Playing music in the dairy parlor provides a steady background of sound. When there is no such background sound, cows tend to react to every sudden loud noise.
Isolation
Cattle are herd animals and become highly stressed when separated from their herd-mates. For example, it has been found that a cow left alone in a stanchion has increased leukocytes in her milk (Lynch and Alexander, 1973).
Whenever possible, loose boxes should be provided in such a way that the isolated animal can maintain sight and sound of the herd-mates.
Why is the Behavior of Dairy Cows Important?
Time Cows Spend on their Feet
- Standing (queuing, waiting) Blood collects in the feet, there is reduced exchange of oxygen and nutrients. Foot health may be compromised.
- Moving Blood is pumped back into circulation from the feet. Fresh blood passing through the feet brings oxygen and nutrients while at the same time cleansing the tissues of poisonous materials. Exercise is a positive activity.
Social Confrontation
A dominant cow, holds her ears and head elevated; A submissive heifer allows her ears and head to sink down. Her eyes may be lidded.
Dominance occurrs as the result of competition for available resources. Therefore, provide 5% more bunk and stall space than there are animals as well as at least one water source for each 20 animals.
Time Cows Spend Lying
Ideally cows should lie in their stalls for 9-14 hours each day for two good reasons:
- They spend more time ruminating. This increases saliva production. Saliva contains bicarbonate which counteracts acidity in the rumen.
- Almost an additional liter of blood passes through the udder of a
cow when she is lying down compared to when she is standing.
If queues form at computerized feeders, increase the number of units.
Several studies have established that cows which stand for long periods have poorer foot health than those that spend time lying (Leonard et al 1994; Galindo and Broom 1994).
In free stalls heifers lie down for shorter periods (6.25 hours) than adult cows (8.39 hours).
Some Ideas to Explore
The Milking Parlor
Check how long each day cows stand in the crowding area. If this totals more than two hours, consider installing a rubberized antislip surface.
Avoid stress-producing experiences (injections, claw trimming) taking place in or near the milking parlor.
Final Words
Study the behavior of animals in your herd. There can be important links between how they behave and the incidence of lameness. Observe what the cows are telling you.
