| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Animal Science, University of Minnesota, St. Paul 55108
2 Animal Welfare Program, The University of British Columbia, 2357 Main Mall, Vancouver, BC, V6T 1Z4, Canada
Corresponding author: Marcia Endres; e-mail: miendres{at}umn.edu.
 |
ABSTRACT |
|---|
 TOP ABSTRACT ACKNOWLEDGEMENTSREFERENCES |
|---|
Key Words: feed barrier • feeding behavior • dairy cow
Fence-line feeding is common for loose-housed cows at commercial dairies. This feeding system was conceived to allow access to feed while preventing the animals from walking and defecating on the feed. However, the design of the physical barrier separating the cows from the feed may also have unintended consequences, such as limiting the cows’ ability to freely access feed and increasing the frequency of aggressive interactions at the feeder.
Increased aggressive interactions at the feeder are thought to limit access to feed, especially during peak-feeding times (Friend and Polan, 1974). In previous research, we showed that increasing space allowance at the feeder reduces competition and improves access to feed, particularly for subordinate cows (DeVries et al., 2004). The design of the feeding facility is known to have profound effects on feeding competition in other farm animals (e.g., Andersen et al., 1999). For cattle, which often displace one another when feeding by swinging and butting with the head, modifications that restrict head and neck movements may be particularly effective in reducing competition and improving access to feed.
Bouissou (1970) found that divisions at the feeder separating the heads of adjacent individuals allowed subordinate cows to feed for longer periods of time. Many modern free stall and drylot dairies use headlocks as a feed barrier. These headlocks provide divisions between the necks of adjacent cows and have a manually activated self-locking feature that can be used to restrain animals. Some previous researchers (e.g., Batchelder, 2000; Brouk et al., 2003) compared headlocks to more open feed-line barriers, but these researchers reported variable results, used limited treatment replicates, and did not address the effects of feed-line barrier on the feeding and social behavior of cows. Thus, the objective of the current study was to determine if a feed-line barrier that provides physical separation between the necks of adjacent cows allows for increased feeding times, particularly at the time of peak feeding activity, and a reduction in aggressive behavior at the feed bunk.
Eight primiparous and 40 multiparous lactating Holstein dairy cows were used in this study. Animals were housed in 4 pens in a free-stall barn at The University of British Columbia Dairy Education and Research Center (Agassiz, British Columbia, Canada) and were managed according to the guidelines set by the Canadian Council on Animal Care (1993). Each experimental pen (width = 7.32 m and length = 13.50 m) contained 12 free stalls (deep bedded with sand) configured in 3 rows. The feed line area of each pen was 7.32 m wide. When the pens were fitted with the post-and-rail barrier, the rail was supported by 3 posts (0.1 m in diameter) that were 3.66 m apart (on center), providing 0.60 m of feeding space per cow. When the pens were fitted with the headlock barrier, there was 1 headlock per cow. Each headlock measured 0.61 m in width, having a 0.18 m wide opening for the neck of the cow, and a 0.43 m separation between the necks of adjacent cows. No cows were restrained in these headlocks at any time during the study. A TMR formulated to meet the NRC (2001) nutrient requirements of high-producing dairy cows was fed ad libitum for the entire experiment. The TMR contained, on a DM basis, 15.7% corn silage, 11.6% grass silage, 10% grass hay, 8.4% alfalfa hay, 17.2% flattened corn and barley mix, and 37.1% concentrate mix. Animals were fed daily at approximately 0600 and 1530 h. Feed was pushed up closer to the cows at 1100 and 2200 h daily to ensure that feed was available to the cows during all hours of the day. The animals were milked twice daily at approximately 0600 and 1700 h.
Samples of the TMR and orts were taken twice during each period and analyzed for DM, NDF, and CP at a commercial laboratory (Norwest Laboratories, Lethbridge, Alberta, Canada) using standard AOAC methods. The DMI for each group for each day on treatment were calculated by subtracting the DM weight of the orts from the DM weight of the fresh feed. Diet NDF and CP averaged 35.5 and 17.6%, respectively, and concentrations were similar between periods and pens. The orts NDF and CP averaged 38.2 and 17.2%, respectively, and the daily orts averaged 6.6 ± 3.6% (mean ± SD) of the fresh feed provided over the course of the experiment.
The 48 cows were divided into groups of 12, balanced by parity (2.9 ± 1.9; mean ± SD), projected 305-d milk production (10,977.9 ± 1919.3 kg), and DIM (113.9 ± 33.1 d), and assigned to 1 of 2 starting conditions: access to the feed bunk via a post-and-rail barrier or via a headlock barrier in a 2 x 2 cross-over design. During the first period, cows were kept for 8 d on one treatment (2 d of adjustment and 6 d of data collection). The feed barriers were then switched between pens, and cows were then kept on the alternative treatment for a second 8-d period.
Feeding and social behavior data were collected using 1 video camera (Panasonic WV-BP330; Osaka, Japan) per pen, a time-lapse videocassette recorder (Panasonic AG-6540), and a video multiplexer (Panasonic WJ-FS 216). The video cameras were located 6 m above the feed bunk of each pen. Red lights (100 W), hung adjacent to the cameras, were used to facilitate recording at night. Animals were marked with unique alphanumeric symbols made with hair dye on the back to allow for individual cow identification when watching the video recordings.
Feeding behavior data were collected from continuous 24-h video recordings using 10-min scan sampling. In preliminary analyses we correlated 1-min video observations with various scan intervals (2, 3, 5, 7, 10, 15, 25, 30, and 60 min) and found near-perfect correlations (r > 0.95) for all scan intervals of 10 min or less, indicating that 10-min scans could be used to adequately and efficiently capture information on feeding behavior. For each scan, an animal was recorded as feeding when its head was completely past the feed barrier and over the feed. These scans were then used to calculate the daily time spent feeding by multiplying the daily number of scans by 10. These scans were also used to calculate the feeding time during the 90-min periods following the delivery of feed when feeding activity was highest.
The number of displacements from the feed bunk per day was collected by continuous observation of 24-h video for the last 3 d of recording for each treatment condition. A displacement was considered to occur when 1 cow ("the actor") contacted another ("the reactor") anywhere along the front half of its body (from the pelvis cranially), causing the reactor to immediately remove its head completely from the feed barrier (DeVries et al., 2004).
For tests of the effect of treatment on DMI, daily feeding time, feeding time during the 90 min after feed delivery, and displacements from the feed bunk, the pen was considered the experimental unit with measures from multiple days and cows averaged to create 1 observation per pen per treatment. Treatment effects on all measures were tested by paired t-tests with 3 degrees of freedom. To test the prediction that cows would respond differently to the headlock treatment, depending upon their ease of access to feed when using the post-and-rail barrier, feeding times during the 90 min after feeding for the 2 treatments were compared using linear regression with the cow as the observational unit. Specifically, to determine if cows changed on average, the intercept was tested for difference from 0, and to determine the extent of the change relative to the initial value, the slope was tested for difference from 1.
Dry matter intake was not affected (t = 0.02, P = 0.98) by treatment, averaging 25.7 ± 0.7 kg per cow per day for both treatments. This result agrees with Brouk et al. (2003) who also reported no differences in pen DMI in an on-farm study comparing headlocks and post-and-rail barriers. Additionally, average feeding time did not differ (t = 1.12, P = 0.34) when cows had access to the feed by the headlock barrier (271.8 ± 3.8 min/d; mean ± SE) compared with the post-and-rail barrier (277.8 ± 3.8 min/d). However, as illustrated in Figure 1
, during periods of peak feeding activity (90 min after feed delivery), there were fewer cows at the feed bunk when using the headlock barrier. Cows spent an average of 47.9 min feeding during these periods when using the headlock barrier compared with 52.0 min when using the post-and-rail barrier (t = 2.87, SE = 1.0; P = 0.005). Feeding times during periods of peak feeding activity were highly related for the 2 treatment conditions (Figure 2; R2 = 0.65, P < 0.001). The slope (0.78 ± 0.09) for the linear relationship was significantly < 1 (F1,46 = 6.48, P = 0.01), and the intercept (7.09 ± 4.58) was not significantly greater than 0 (F1,46 = 2.39, P = 0.13). Thus, cows with lower feeding times relative to group mates when using the post-and-rail barrier showed more similar feeding times to group mates when using the headlock barrier. This result agrees with Bouissou (1970), who reported that divisions at the feeder separating the heads of side-by-side individuals allowed subordinate cows better access to feed. Cook et al. (2004) suggest that dominant cows sort fresh feed, and that low-ranking cows with low feed access may be forced to alter daily activity patterns and feed at the bunk only after dominant cows have accessed the fresh feed. Therefore, providing equal access to fresh feed may be particularly important in reducing the variation in diet quality consumed by the cows.
|
|
In conclusion, there was no difference in overall feeding time between the 2 barriers, but the headlock barrier allowed for more equal access to feed for cows during peak feeding periods. Use of a headlock barrier also reduced the frequency of aggressive interactions at the feed bunk. These aggressive interactions are known to increase with stocking density (e.g., DeVries et al., 2004), so in the future, researchers should examine the effects of barrier design in relation to stocking rate. Moreover, we encourage further work examining the effects of using head and body dividers to further reduce aggression at the feed bunk.
|
ACKNOWLEDGEMENTS |
|---|
|
TOPABSTRACTACKNOWLEDGEMENTSREFERENCES |
|---|
Received for publication February 9, 2005. Accepted for publication April 7, 2005.
|
REFERENCES |
|---|
|
TOPABSTRACTACKNOWLEDGEMENTSREFERENCES |
|---|
This article has been cited by other articles:
|
|
 |
|
  T. J. DeVries and M. A. G. von Keyserlingk Feed stalls affect the social and feeding behavior of lactating dairy cows. J Dairy Sci, September 1, 2006; 89(9): 3522 - 3531. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Huzzey, T. J. DeVries, P. Valois, and M. A. G. von Keyserlingk Stocking Density and Feed Barrier Design Affect the Feeding and Social Behavior of Dairy Cattle J Dairy Sci, January 1, 2006; 89(1): 126 - 133. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. L. Mentink and N. B. Cook Short Communication: Feed Bunk Utilization in Dairy Cows Housed in Pens with Either Two or Three Rows of Free Stalls J Dairy Sci, January 1, 2006; 89(1): 134 - 138. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. J. DeVries, M. A. G. von Keyserlingk, and K. A. Beauchemin Frequency of Feed Delivery Affects the Behavior of Lactating Dairy Cows J Dairy Sci, October 1, 2005; 88(10): 3553 - 3562. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
