| | Feedlot cattle are comprised of both beef and dairy breeds. Differences in carcass characteristics, body size, and efficiencies of gain between these breeds have long been noted. One study reported that Holsteins are 13% more efficient than Herefords and another reported that there was a 13% reduction in gain/unit of feed for Holstein over Charolais steers. Other researchers concluded that the beef progeny of holstein cows required 27% more feed per kg gain than beef progeny.
However, differences in breed feeding behaviours and how these differences might affect production efficiency in the feedlot are not well known. Restricted feeding of feedlot steers is a common practice which can result in increased efficiency of feed conversion but the comparative efficiencies of different breeds on restricted versus ad libitum fed diets has not been closely examined.
Despite the tremendous impact that management can have on animal performance, surprisingly little is known about the feeding patterns of individuals within a pen and how specific factors such as weather, amount of feed presented, frequency of feeding, or time of feeding may affect intake and performance. For example, anecdotal evidence suggests that cattle consume large amounts of feed prior to storms, yet little concrete evidence has been gathered to test these claims. Other studies that attempt to correlate weather patterns with eating behaviour show that strong relationships exist at extremes in barometric pressure and ambient air temperatures.
Beef and dairy breeds fed for slaughter are thought to have similar nutrient requirements at the same empty body weight. However, environmental variables may affect the breeds differently due to body composition and haircoat differences. Skin thickness, haircoat, rumen volume, rate of digestion, and metabolic efficiency might all affect behavioural responses to environmental and managerial variables and differ among the breeds.
Differences due to feeding regime, feeding patterns and climatic conditions may provide valuable insight into management strategies for feeding different breeds. For these reasons my colleagues and I designed a study in which we could 1) compare the feeding behaviours and performance of Charolais and Holstein steers fed for slaughter under either ad-libitum or restricted feeding regimes and 2) compare weather variables with daily bunk attendance frequency and duration.
Thirty Charolais (C) and 29 Holstein (H) steers of comparable weight (432 ± 30 kg) were randomly allotted to one of 2 pens per breed. Following a 10 day adaptation period, all animals were fed an 80:20 barley grain/barley silage mix ad-libitum for 3 weeks. The following 3 week feeding period was restricted (R) to 95% of the previous 3 week daily intake. This 6 week process was then repeated. Feeding behaviour data was obtained using a radio frequency system that recorded the animal identification number, time, duration and location along the bunk during each visit over a 24 h period.
Animals were weighed at 21 day intervals. Performance parameters measured included feed intake (taken at weekly intervals on a pen basis) feed efficiency and ADG. Weather data included air temperature (AT), relative humidity (RH), barometric pressure (BP) and wind speed (WS).
We found that the C steers spent significantly less time at the feed bunk made fewer visits, consumed the same amount of feed, gained more rapidly and were more feed efficient than the H steers (See Tables 1 and 2).
All ad libitum fed steers spent less time at the feed bunk, made fewer visits, consumed more feed and had higher daily gains compared to restrictively fed steers. However, this did not translate into better feed conversion rates.
H steers fed restrictively had the lowest bunk attendance duration while C steers fed ad libitum had the highest bunk attendance duration. Regardless of feeding regime C cattle performed better than H cattle. Weather variables had significant effects on bunk attendance patterns of C and H steers that varied with the feeding regime. The bunk attendance time for C steers was more affected by changes in air temperature, relative humidity, and barometric pressure than H steers, however, this did not relate to differences in performance.
We concluded that weather does affect bunk attendance patterns that change with breed and feeding regimen. C steers appear to have been more affected by weather changes. This means that behavioural responses to the environment may be breed dependant. To get a clearer picture we need to conduct long term studies at various climatic locations.
Table 1. Effect of breed and feeding regimen on the duration (min) and frequency of bunk attendance over an 85d feeding period
 | Charolais | Holstein |
| Ad libitum | Restricted | Ad libitum | Restricted |
| Duration | 102.43 ± .89b | 93.77 ± .89d | 96.63 ± .91c | 110.72 ± .91a |
| Frequency | 10.87 ± .10b | 9.13 ± .10c | 11.25 ± .12a | 10.75 ± .10b |
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a,b,c,d Within breed rows with different superscripts differ (P< .005).
Table 2. Effect of breed (n=59) and feeding regimen on animal DM intake, ADG, and feed:gain efficiency over an 85d feeding period
| Breed | Feeding Regimen |
| Charolais | Holstein | Ad libitum | Restricted |
| DM Intake (kg) | 8.27 ± .06a | 8.48 ± .06b | 8.62 ± .06a | 8.13 ± .06b |
| ADG (kg) | 1.36 ± .08a | .99 ± .08b | 1.34 ± .08a | 1.01 ± .08b |
| F:G | 6.20 ± .19b | 8.71 ± .19a | 7.69 ± .19 | 7.22 ± .19 |
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a,b Within breed or feeding category columns with different superscripts differ (P< .005).
Prepared By:
Karen Schwartzkopf-Genswein, Alberta Agriculture Food and Rural Development, Lethbridge
S. Atwood, Agriculture and Agri-Food Canada, Lethbridge, AB
R. Silasi, Agriculture and Agri-Food Canada, Lethbridge, AB
A., T. A. McAllister, Agriculture and Agri-Food Canada, Lethbridge, AB
for the Southern Alberta Beef Review - April/May, 2001. Volume 3, Issue 2
Document maintained by Ken Ziegler, Ag Info Centre, Alberta Agriculture and Food. |
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