Impact of Headlocks Upon Milk Production and Intake of Dairy Cattle

M.J. Brouk, J.F. Smith and J.P. Harner, III.
Kansas State University
Manhattan, KS

Introduction

Headlocks or self-locking stanchions have been utilized for animal restraint necessary for many routine dairy husbandry procedures for several decades. Headlocks allow a single person to restrain a group of animals increasing the labor efficiency of routine animal care including breeding, pregnancy exam, vaccination, injections, and other procedures.Within the last decade, some concerns have been raised about the effects of headlocksupon milk production and feed intake. The following is a review of the published reports and a study recently completed at K-State as part of the KSU Cow Comfort Consortium.

Headlocks Versus Neckrails

One of the major concerns of dairy producers and building contractors is reducing physical barriers to milk production and feed intake. The use of headlocks for routine procedures may increase labor efficiency, but does it adversely affect animal performance? Batchelder (2000) reported that dry matter intakes were reduced (P<0.05) by 2.8 lb/c/d when headlocks were utilized rather than neckrails. When pens were overcrowed by 30%, headlocks reduced (P<0.05) feed intake 1.6 lb/c/d. Differences in milk production were not significant (P>0.05). This study utilized 20 animals per treatment in the uncrowded and 26 animals in the over-crowded treatment. Based on the data, one could suggest that if feed intake was reduced by 1.6 to 2.8 lb/c/d, milk production should

have been reduced 4 to 7 lb/c/d. Thus, a study was implemented during the summer of 2000 to determine the effects of headlocks and neckrails upon milk production and feed intake of cows housed on a commercial dairy in northeastern Kansas.

Cows were housed in head-to-head 2-row freestall buildings equipped with 100 freestalls and identical stall fans and low-pressure feedline sprinkling systems. Two barns were selected and each was stocked with 108 mid lactation Holstein cows (55 heifers and 53 cows). Each barn contained 220 ft of bunk space with 110 headlocks and 100 freestalls. A total of 108 animals were allotted to each barn, resulting in an overstocking of stalls by 108% and headlocks stocked at 98% of capacity. Headlocks were manufactured by a local company and utilized 2 linear ft per lock. Animals were blocked by lactation number, days in milk, production and randomly assigned to one of two treatments. Treatments were headlocks or neckrails. A switchback design was utilized and the treatments (headlocks and neckrails) were switched between the buildings. Two 4-week periods were utilized. Cows were milked 3x and amounts recorded electronically each milking utilizing an automatic identification system. Both barns received an identical TMR and the amounts fed and refused were recorded daily. Dry matter of the feed and refusals were determined twice weekly.

Average dry matter intakes (Figure 1) were similar (P>0.05) for both treatments averaging 51.8 and 50.4 lb/c/d for neckrail and headlock treatments respectively. Average milk production (Figure 2) was similar (P>0.05) for both neckrail and headlock treatments. Data from this study indicated that on a commercial dairy, headlocks did not adversely affect milk production or dry matter intake of cattle trained to headlocks. Removal of the headlock did not increase milk production or feed intake.

In summary, it does not appear that headlocks adversely affect milk production or feed intake on commercial dairy farms. It should be emphasized that the animals involved in this study had been previously exposed to headlocks and were trained to use them.

Figure 1. Intake of Dairy Cattle Exposed to Neckrails and Headlocks.

Figure 2. Milk Production of Dairy Cattle Exposed to Neckrails and Headlocks.

Effect of Restraint Time

Several studies have examined the effects of restraint time upon milk production and feed intake of dairy cattle. A study (Shipka, et al., 1995) completed in the spring of 1994 showed no significant affects upon milk production (P>0.10) or intake (P>0.60) when cattle were locked for 4 hours from 0700 to 1100 hours on seven consecutive days. In addition, cattle spent similar amounts of time standing following lock-up. The authors concluded that extended lock-up for 4 hours did not adversely affect the cattle.

Another report (Arave, et al., 1996a) demonstrated that locking cattle for 4 continuous hours (0900 to1300 hours) during the summer months resulted in a significant decrease (P<0.001) in milk production. Cows that were locked produced 6.4 lb/c/d or 7.8% less milk than when not restrained for 4 continuous hours. Feed intake was not significantly impacted by restraint time. In addition to reduced milk production, serum cortisol levels were also increased (P<0.001) indicating a greater level of stress when locked for 4 continuous hours during the summer months (Arave, et al., 1996b).

0.05) in milk production and feed intake. Cattle locked for 4 continuous hours produced identical amounts of milk and consumed identical amounts of feed as compared to controls. Mean plasma cortisol levels (12.7 vs 15.5 µg/dl) were similar (P=0.27) for restrained and control animals indicating similar stress levels in both groups. Following 4 hours of lock-up, cattle rested more often (P<0.01) than did controls. Cattle that were locked spent a smaller (P<0.05) percentage of the time eating but drinking activities were unaffected (P>0.05) as compared to controls. Authors concluded that the use of self-locking stanchions for up to 4 continuous hours did not adversely affect the cattle.

Restraint time can add to the stress level of cattle as demonstrated in one of the studies. During cool environmental conditions, locking animals for 4 continuous hours did not reduce feed intake or milk production in two studies. The only adverse affects of 4 continuous hours of lock-up occurred during the summer months when cattle were locked from 0900 to 1300 hours. Management of headlocks to reduce lock time during the summer months is necessary to reduce animal stress. In general, lock time should be kept to the absolute minimum. Based on the findings of these studies, lock times should be kept to four hours or less. Minimizing lock time to 1-2 hours per day would be recommended. During summer months, un-shaded cattle should not be locked during the late morning and afternoon hours.

Sloping the Feed Barrier

Hansen and Pallesen (1994) reported that sloping the feed barrier away from the cow 20° increased the radius of the cows’ reach by 5.5 inches. This allowed cows access to 2.4 lb of additional feed and reduced remaining feed by 50%. Sloping the feed barrier away from the cow may be more important when the manger wall exceeds 8 inches. Sloping the barrier regains some of the bunk space lost due to wider manger walls.

Summary

The majority of the data shows that headlocks do not reduce milk production or feed intake. Prudent use of headlocks increases labor efficiency of a commercial dairy. Managing a dairy without headlocks is a challenge because animals must be sorted and 4 worked off the milking parlor flow. In the case of large milking parlors, 100-500 cows are released each hour. Animals released from the parlor must be sorted and treated without reducing parlor efficiency. If the treatment facilities are not able to handle the animal flow created by the milking parlor, a bottleneck is created for the dairy. For many routine procedures, headlocks offer the simplest and most cost effective alternative. It is important to note that headlocks can be miss-managed. This is especially true during the summer months. Locking animals for extended periods without access to water or shade may have adverse affects during summer heat stress. It is important to limit lock-up time to the minimum. Consideration should also be given to training heifers to headlocks prior to calving. The studies reported, utilized cattle that were familiar with headlocks. It is very likely that untrained heifers may be reluctant to utilize headlocks. If this occurs, intake could be limited during the first few days of lactation. If heifers are not trained to headlocks prior to calving, one should determine if heifers lock-up each morning during the first week of lactation. Heifers that do not lock-up may not be utilizing the headlocks and therefore not eating. Headlocks can be successfully utilized on a dairy. The critical question is how will they be managed! Successful managers of headlocks minimize restraint time, push-up or feed pens often (6-8 times per day) and avoid utilization of headlocks during late morning and afternoon during the summer months.

Source: Kansas State University
Author: Brouck, Smith