Dairy cattle housed in freestall barns are normally separated from the feed delivery area by some sort of barrier. Barriers are important as they prevent cattle from walking and defecating on the feed.

They have been designed to allow cows unrestricted access to feed; however, the design and management of these barriers may affect the ability of cows to access feed.

One particular management factor that can influence the ability of cows to access feed is the amount of available feedbunk space. Previous work by our group has shown that increased space allowance per cow at the bunk reduces competition and improves bunk access, especially for subordinate animals. Even though decreasing stocking density at the feedbunk will reduce competition and increase feed access, competition is not eliminated at the feedbunk. This suggests that there are additional factors affecting competition for food resources by lactating dairy cows.

In our previous research we have shown that the use of a feed barrier that provides some physical separation between adjacent cows (such as headlocks) can reduce competition (displacements) at the feedbunk and that subordinate animals experience the greatest decreases in competition. Unfortunately, cows also show reduced feeding time when fed using a headlock feed barrier, possibly due to a learned aversion to being restrained in locking headlocks.

Interestingly, researchers have demonstrated in other species, such as pigs, that providing partitions that separate the bodies of adjacent animals can have profound effects on reducing competition and allowing animals to feed for longer periods of time. These effects had not yet been shown in group-housed dairy cattle. Therefore, the first objective of this study was to provide further evidence that increased bunkspace reduces the frequency of aggressive behavior at the feedbunk and improves feed access. The second objective was to determine if the addition of feedstall partitions between adjacent cows even further reduces aggressive behavior at the feedbunk and improves feed access.

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Twenty-four lactating Holstein cows were subjected to each of three treatments in three successive 10-day treatment periods using a 3x3 Latin square design. The treatments tested were:

1. 0.64 meters (approximately 2 feet) of feedbunk space per cow
2. 0.92 meters (approximately 3 feet) of feedbunk space per cow
3. feedstalls (0.92 meters of feedbunk space per cow plus feedstall partitions separating adjacent cows)

Time-lapse video was used to record the feeding and standing behavior, as well as the aggressive behavior (displacements) displayed at the feedbunk by the cows. To meet our first and second objectives, we compared the data from the 0.64 meters per cow to the 0.92 meters per cow treatment and the 0.92 meters per cow to the feedstall treatment, respectively. Total daily feeding time increased when feedbunk space was increased from 0.64 to 0.92 meters per cow. Further, the time spent standing in the feeding area while not feeding and the frequency of aggressive interactions at the feedbunk decreased when more bunk space was provided.

The addition of the feedstalls resulted in an even further increase in feeding time and decrease in aggressive interactions for the cows compared to when they were provided with 0.92 meters per cow of bunk space. The feedstalls also forced cows to change the strategy by which they displaced others from the feedbunk. The presence of the feedstalls forced the cows to initiate contact at the rear of the animal they were displacing rather than from the front or side as in the case of the other two treatments. Further, subordinate cows experienced the greatest decreases in the number of times they were displaced per day when they were provided additional feeding space, and this effect was strongest when the feedstalls were present.

The results indicated that the provision of increased feedbunk space, particularly when combined with feedstalls, will improve access to feed and reduce competition at the feedbunk, especially for subordinate cows. We predict that this may be important for transition cows, as improved bunk access may help these animals maximize their feed intake to meet their energy demands. To verify this, our current research is directed at determining the implications of increased feed access and reduced competition at the feedbunk on the dry matter intake, milk production and health of lactating dairy cows, particularly those in early lactation. PD

References omitted but are available upon request at editor@progressivedairy.com

—Excerpts from University of British Columbia Research Reports, Vol. 7, No. 2

Trevor DeVries Assistant Professor

Does your follow-up research indicate that reduced feedbunk competition is more beneficial to transition cows than cows in other stages of lactation?

Clearly there are benefits for providing more space, particularly with feed stalls, to cows as shown in this study. However, if producers have limited resources that only enable them to install feed stalls in one area of their facility I strongly encourage them to do so in the transition cow area. Results of follow-up research by colleagues at the UBC Animal Welfare Program and myself indicate that decreasing competition and increasing access to the feedbunk may be particularly important for transition cows. In one study (Huzzey et al. 2007. Journal of Dairy Science), it was demonstrated that decreased DMI before calving increases the risk of disease post-calving. Further, DMI was positively correlated with feeding time, particularly for those animals at high risk for disease. In another study (Hosseinkhani et al. Journal of Dairy Science in press), we demonstrated that increased feedbunk competition for transition cows promotes feeding behavior patterns that result in some cows having access to the bunk after feed sorting has occurred, increasing the between-cow variation in diet consumed.

tdevries@kemptvillec.uoguelph.ca

Trevor DeVries and Marina von Keyserlingk, University of British Columbia