In a new study, Texas A&M University researchers discovered that keeping cows in self-locking head stanchions for extended periods of time had a negative impact on dairy cow performance.
Lock-up time is the amount of time an animal spends restrained or locked into a head stanchion per day, which is typically found at dairy farm feed bunks. Dairy cattle are confined on a regular basis for pregnancy testing, artificial insemination, veterinary treatments and examinations, vaccinations, heat detection, and feeding.
However, it has been discovered that using a head lock as a method of restraint can have a negative impact on an individual animal’s well-being and productive performance within a herd, especially if the system is used outside of the normal management routine.
According to studies, when this management practise is not followed correctly and cows are restrained for extended periods of time (>4 hours daily), the animals experience varying levels of stress, which can jeopardise their production, health, and welfare.
Researchers investigated the effects of prolonged or extended lock-up time in dairy cattle in this study.
Milk production effects
Reduced milk production in cows is common when lock-up time exceeds 4 hours, according to observations from various studies. Scientists from the University of Cambridge discovered that when cows are deprived of feeding and lying for more than 4 hours during hoof trimming, milk yield is reduced by 2 litres per day for 3 days.
Stress is linked to longer periods of lock-up time. According to research, stress alters mammary homeostasis in dairy cows. It has been proposed that the stress caused by a prolonged lock-up time may result in suboptimal performance of alveoli in the mammary gland, resulting in decreased milk yield, increased mastitis incidence, and lower milk quality.
A similar study on the effects of lying or standing on mammary blood flow in dairy cows found that lying time resulted in 24% more blood flow to the mammary glands due to cardiovascular homoeostasis caused by gravity. As a result, decreased lying time as a result of prolonged lock-up time may be another explanation for the decrease in daily milk yield in dairy cattle.
Cow protection
Recent research has linked headlock restraint for more than 4 hours per day to increased aggression in dairy cattle. This aggressive behaviour was discovered to be the result of frustration or discomfort experienced during the restraint period. Aggressive behaviour in dairy cows has been linked to lower reproductive performance, including lower conception rates for heifers at first service, according to a recent study.
When compared to cows in an extended lock-up period, normal herd management increased the amount of time cows spent lying, self-grooming, ruminating, and eating. The altered time budget management as a result of longer lock-up time (>4h) has an impact on overall daily cow behaviour. In another study, the authors discovered that cows who were denied lying for 2 hours lost their feeding time for the next 24 hours, whereas cows who were denied lying for 4 hours required 41 hours to regain their feeding time.
Lameness and heat exhaustion
Lameness is a serious problem on dairy farms all over the world, and studies show that longer lockup times may exacerbate the problem. Although studies examining the direct relationship between lock-up times and lameness are lacking, some research work suggests the possibility of the effect.
Researchers discovered that cows exposed to narrow feed alleys and obstructed lunge space, resulting in increased cow standing, were more prone to lameness in their study published in the Journal of Dairy Science. According to another study, longer lock-up time contributes to deviations from the regular daily time budget, indicating variability in lying time and lying bouts that predispose cows to lameness. However, researchers recommend that the potential direct link between extended lock-up time and lameness be investigated further.
Furthermore, studies found that extended lock-up time (>4h) was more detrimental in hotter temperatures than in mild temperatures due to the additive effect of restraint stress and heat stress, implying that it is more critical to minimise lock-up time in extreme heat environments to reduce the detrimental effects of these stressors.
Cow in transition
During the transition period, the cows require more lock-up time. Cows change their behaviour during the transition period, which is defined as the three weeks before and three weeks after calving. The transition period is a critical period in the life of a dairy cow because of the animal’s susceptibility to disease and the nutritional, physiological, and social changes that occur around the time of calving.
However, because of the need to closely monitor the animal for post-calving evaluations and treatment of health disorders, dairy cows in the transition period are more prone to longer headlock times. As a result, transition cow stressors should be limited, and lock-up management routines should be closely monitored for the effects on the transition cow’s time budget and cow comfort.
What is the ideal time for head lock-up?
The head lock-up time studies fall short of defining the appropriate time without causing health and production issues. Several studies have found that keeping cows in self-locking head stanchions for an extended period of time (>4 hours per day) can have a negative impact on dairy cow performance. The emphasis should be on properly managing the farm by limiting restraint time to less than 4 hours per day and avoiding the use of headlocks during the late morning and afternoon hours of the summer months.
Mitch Theurer and Mike Brad, dairy consultants affiliated with the Standard Nutrition Company, recommended the following lock-up times in their report focusing on factors that limit cows’ time budget:
- Lock-up times should be kept to a maximum of two hours.
- Schedule lockup times to coincide with feedings and push cows to the bunk, rather than setting the locks 3 hours before the event.
- During lock-up, always keep plenty of fresh feed on hand.
Researchers proposed future research work to focus on the effects of different lock-up times on the health and production of dairy cows in order to better appropriate lock-up time.
