The author is president of the William H. Miner Agricultural Research Institute, Chazy, NY.
Self-locking stanchions, or headlocks, have become ubiquitous on dairy farms to restrain cattle for activities such as pregnancy checks, artificial insemination, and health management. But, already in 1997, Jack Albright at Purdue University was cautioning about the potential problems of extended lock-up times in his textbook, The Behaviour of Cattle.
Recently in the aforementioned Hoard’s Dairyman Intel, veterinarian and farm owner Don Niles stated that some farms can stop using self-locking stanchions with the advent of modern technologies such as activity collars. Activity monitoring systems won’t fit for every farm, and self-locking stanchions will be an important management tool well into the future for many dairy farms. But, in my opinion, he rightly suggested that every farm needs to assess the time that cows spend standing in headlocks.
Extended lock-up is stressful
Recently, Texas A&M University faculty thoroughly reviewed the published literature on the consequences of long lock-up times. Based on published research, they defined extended lock-up time as greater than 4 hours per day. Of course, negative consequences could be observed prior to 4 hours, but this was their definition based on the research they reviewed.
The authors divided the cow responses to excessive lock-up time into several categories: animal stress, rumination, milk yield and components, reproduction, lameness, lying time, and frustration or discomfort. All of these responses are important to both the cow and the herd’s profitability.
The authors proposed a biological mechanism for how extended lock-up times stress the dairy cow. When cows are restrained in self-locking stanchions, they may have limited access to feed and water, less lying time, and greater human presence. Any negative consequence would be even more pronounced under heat stress. The net effect is greater blood cortisol, which reflects the elevated stress. Negative consequences then arise for milk production, reproduction, and health.
The cow responses
Lock-up time greater than four hours daily reduces milk production. The Texas A&M review cited work showing about a 4 pound per day drop in milk yield for cows deprived of feeding and lying time for greater than four hours daily.
A pair of studies were conducted at Purdue University and Utah State University by Jack Albright and Clive Arave that are often referenced since they comprehensively measured the behavior, health, and productivity responses to extended lock-up time. The Purdue work compared four hours daily versus less than 1.5 hours daily of lock-up time and observed that, in the short term, feed intake and milk yield were not affected although milk protein decreased. But cows spent more time lying down after being released from the headlocks, and rumination time was depressed following extended lock up — not a good combination! Extended lock up times also contribute to more time standing, which in turn raises the risk of hoof disease and lameness.
Interestingly, grooming behavior spiked for restrained cows and was one of the first behaviors performed upon release. This work by Albright and his colleagues was the first to suggest that grooming is a behavioral need of dairy cattle.
The companion study conducted at Utah State University found lower milk yield and elevated blood cortisol during the summer months for cows enduring extended lock-up time. Cows experienced more stress when locked up during the heat of the summer. The review emphasizes the need to minimize lock-up time during hot weather so that the negative effects of these two stressors are not compounded.
Take extra care
Excessive time spent in self-locking stanchions is especially detrimental to transition cows. They are often locked up to facilitate health checks, but we need to be careful to avoid upsetting the cow’s time budget behaviors. Excessive standing time and less lying are always detrimental, and if feed is not pushed up within easy reach, then feed intake can be reduced. Given the strong relationship between feed intake and metabolic health in fresh cows, we need to ensure that extended lock-up times do not counteract the potential positives associated with routine fresh-cow health checks.
Research also tells us that longer lock-up times elicit aggressive behavior because of the cow feeling discomfort or frustration. Self-locking stanchions actually reduce aggression at the feed bunk and boost feed access for more subordinate cows versus a simpler post and rail system. Still, we need to ensure that lock-up time is managed.
The design and management of the feed barrier should allow cows to exert the least amount of force while eating. So, feed push-up strategy and possibly tilting headlocks become important considerations.
Cows will exert nearly 500 pounds of force against the feed barrier in an effort to reach feed. That is about twice the level of pressure that can cause injury. About 80% of the pressure occurs within the first hour after feed delivery, and the pressure climbs as the cow reaches its limit for stretching forward to access the feed. The bottom line is that we need to make sure feed is within easy access of the cow if we want to use headlocks successfully.
How long is too long?
Commonly observed time spent locked in headlocks ranges from essentially zero to four hours or more daily. Based on the reviewed research by the Texas A&M team, four or more hours daily is clearly detrimental. More work is needed to better define recommended lock-up times, especially in hot summer months.
It is worth mentioning that research from the University of Nebraska nearly 20 years ago observed that cows locked in headlocks consumed feed for about one hour, and then over the next hour, about 30% to 40% of them gradually started ruminating. This eating time agrees with published data on meal length.
A takeaway is that we cannot assume that cows are going to be actively eating when locked in headlocks just because feed is in front of them. A far better behavioral scenario would be to release the cows within an hour, as the meal is ending, and allow them to lie down to ruminate.
The Nebraska work concluded that routine lock-up of cows greater than one hour had the potential to negatively affect the normal feeding behavior of cattle. This recommendation of no more than an hour ought to preclude most negative behavior, health, or productive responses.
Minimize lock-up time
Headlocks versus cow comfort should not be an “either-or” proposition. Although activity monitors are growing in popularity all the time, self-locking stanchions make for efficient management of cattle housed in pens. The challenge is to avoid extended lock-up times and aim for an hour or less for their routine use. Time in the headlock is time you have taken away from the cow to do as she chooses, so manage it thoughtfully.