Commingling or mixing of cattle

In a large Canadian study, Ribble et al. (Reference Ribble, Meek, Shewen, Guichon and Jim1995) traced 32,646 spring-born steer calves that entered a large feedlot back to the auction market where they were purchased. Individual cow-calf producers contributed a median of 2 calves per truckload that arrived at the feedlot. Results suggested that increased commingling or mixing of calves from different farms/ranches at the auction market to make up a truckload of cattle increased the risk of fatal fibrinous pneumonia in the calves following feedlot entry. An association between commingling of cattle and development of BRD was also reported by Alexander et al. (Reference Alexander, MacVean and Salmon1989).

Price premiums are paid for larger lot sizes or groups of uniform steers and heifers at the auction market. Sartwelle et al. (Reference Sartwelle, Brazle, Mintert, Schroeder and Langemeier1996) reported that a lot size of 65 steers sold for an average premium of $6.37/45.45 kg compared to the price paid for a one-head lot. They suggested that cattle buyers prefer to purchase larger groups of cattle to minimize health problems associated with commingling. In addition, the purchase of larger lots of cattle allows the load to be completed more quickly, thereby reducing the amount of time between purchase and arrival at the feedlot. Some buyers view the discount in price for cattle bought as singles or in small groups as an opportunity to lower their initial investment; however, studies have shown that purchasing practices that increase commingling increase the risk of BRD (Alexander et al., Reference Alexander, MacVean and Salmon1989; Ribble et al., Reference Ribble, Meek, Shewen, Guichon and Jim1995; Step et al., Reference Step, Krehbiel, DePra, Cranston, Fulton, Kirkpatrick, Gill, Payton, Montelongo and Confer2008).

Cow-calf producers can manage their herds to produce larger numbers of uniform calves at marketing time. Differences in age and weight can be minimized by utilizing a shorter breeding season, and uniformity of calves can be further enhanced through genetic selection.

Step et al. (Reference Step, Krehbiel, DePra, Cranston, Fulton, Kirkpatrick, Gill, Payton, Montelongo and Confer2008) evaluated the effect of commingling beef steers from different sources on BRD and performance during a 42-day receiving period. Three groups were compared: (1) steers purchased from a single ranch (RANCH); (2) steers purchased from multiple sources (auction markets; MARKET); and (3) a portion of MARKET steers commingled with a portion of RANCH steers (COMM). Total morbidity (sum of percent calves treated once, twice and thrice) during the 42-day study was 11.1, 41.9 and 22.6% for RANCH, MARKET and COMM steers, respectively. Mortality due to BRD was greater (P=0.03) in MARKET and COMM calves than in RANCH calves. In addition, health costs and total costs were greater (P⩽0.02) in MARKET and COMM steers compared to RANCH steers; however, cost of gain did not differ (P=0.22) among calf origin treatments. Calves in the RANCH group tended (P=0.06) to gain better during the 42-day study than MARKET and COMM calves, but no other differences (P>0.10) in performance were reported.

Weaning practices and BRD

Step et al. (Reference Step, Krehbiel, DePra, Cranston, Fulton, Kirkpatrick, Gill, Payton, Montelongo and Confer2008) compared calves simultaneously weaned and shipped to the research feedlot (WEAN) to those weaned and held on the ranch for 45 days (WEAN45) and those weaned 45 days and vaccinated twice with a modified-live viral vaccine and administered one dose of Mannheimia haemolytica toxoid before shipment to the research feedlot (WEANVAC45). Steers purchased from multiple auction markets (MARKET) served as controls. Calves in the WEAN, WEAN45 and MARKET groups were not vaccinated prior to arrival into the feedlot.

Dry matter intake expressed as a percentage of bodyweight was greater (P<0.001) for MARKET, WEAN45 and WEANVAC45 than WEAN calves across the 42-day study period. Average daily gain and gain efficiency did not differ (P>0.05) during the study.

Total morbidity percentage in the study and percentage of calves treated once were greater (P<0.001) in the MARKET and WEAN calves. This difference was dramatic; total morbidity was 41.9 and 35.1% in the MARKET and WEAN groups, respectively, and 5.9 and 9.5% in the WEAN45 and WEANVAC45 groups. Calves in the MARKET treatment group were pulled for BRD and treated sooner (P=0.004) after arrival than WEAN and WEAN45 calves. Percentage of calves treated twice was 5–10-fold greater (P=0.05) for calves in the WEAN group compared to those in the WEAN45 and WEANVAC45 groups.

The study by Step et al. (Reference Step, Krehbiel, DePra, Cranston, Fulton, Kirkpatrick, Gill, Payton, Montelongo and Confer2008) also compared the health costs of weaning management strategies. Health costs were higher (P<0.001) for calves in the MARKET ($13.54/head) and WEAN ($13.24/head) groups than in the WEAN45 ($8.30/head) and WEANVAC45 ($8.93/head) groups. Cost of bodyweight gain tended (P=0.07) to be higher in the MARKET ($1.65/kg) and WEAN ($1.63/kg) calves compared to WEAN45 ($1.32/kg) and WEANVAC45 ($1.45/kg) calves. Weaning on the farm or ranch for 45 days prior to shipment resulted in improved health and performance compared to those for calves shipped to the feedlot immediately after weaning or those for calves purchased through auction markets. Vaccinating calves on the ranch and waiting 45 days to ship calves offered no health and performance advantages over weaning and holding the calves for 45 days alone. This study suggests that utilizing either of these two strategies should result in higher market prices, largely because of lower risk of BRD after arrival at the feed yard.

Seeger et al. (Reference Seeger, Grotelueschen, Stokka and Sides2008) conducted a study to compare health, performance, carcass traits and economic value of auction-origin steer calves with unknown health history to two groups of auction-origin steers that were administered a herd of origin health protocol with at least a 45-day weaning period. The steers were fed in a commercial feedlot until harvest, with time on feed ranging from 145.7 to 161.4 days. Total morbidity (treated once, twice and thrice) for the entire feeding period was higher (P=0.0079) in the group with unknown history (42.63%) compared to the two groups weaned at least 45 days and administered a herd of origin protocol (15.44 and 15.41%). Average daily gain was highest (1.56 kg/day; P<0.05) in one of the groups weaned 45 days compared to calves with unknown history (1.50 kg/day); the other group was intermediate (1.55 kg/day). Daily dry matter intake was lowest (P<0.05) in calves of unknown health management history, but feed efficiency (kg feed/kg gain) did not differ (P>0.05) between groups. When days on feed was adjusted to a common 145.7 days, profit when calves were sold at harvest was $33.71/head greater in one group of calves administered a herd of origin health protocol than calves with unknown health history, and $22.35/head greater than the other group of calves administered a herd of origin health protocol. While recognizing that differences in carcass value, although unrelated to health management programs, could confound the economic analysis, these studies suggest that calves weaned at least 45 days have more value when marketed than those not weaned and with an unknown health history. Personnel providing health management in the study feedlot were highly skilled, making it tempting to postulate that the value of calves weaned at least 45 days and vaccinated may have even more value if there is a shortage of skilled labor to provide health care for the calves.

Prices paid in the marketplace also support the suggestion that calves weaned at least 45 days have more value. Based on several years of video-auction sales data, King et al. (Reference King, Salman, Wittum, Odde, Seeger, Grotelueschen, Rogers and Quakenbush2006) reported price premiums of $2.47/45.45 kg to $7.91/45.45 kg from 1995 to 2005 for calves that were weaned ≥45 days and had been vaccinated against BRD (VAC45) compared to similar calves that were not in a certified health program, were not weaned before shipment, and had not been vaccinated against BRD. There were no unvaccinated calves in the study that had been weaned ≥45 days to compare. Price premiums paid for calves in a less intensive (VAC34) certified health program, vaccinated against BRD but not weaned prior to delivery, ranged from $0.99/45.45 kg to $3.47/45.45 kg. Cattle buyers were willing to pay more for calves vaccinated and weaned ≥45 days than those vaccinated and not weaned. The price premium paid for calves in both the VAC34 and VAC45 health programs increased over time, both as dollars/45.45 kg and as a percentage of base market price from 1995 to 2005.

Cattle disposition and BRD

Disposition is a measure of how docile or wild an animal is, especially during human–animal interaction. Cattle disposition has not been historically associated with health, BRD in particular, or performance. Busby et al. (Reference Busby, Strohbehn, Beedle and King2006) used a Disposition Scoring System developed by the Beef Improvement Federation to classify 13,315 feedlot cattle as docile, restless, nervous, flighty, aggressive, or very aggressive. For analysis, the six classifications were compressed into three; docile, restless and aggressive. During the entire feeding period, average daily gain differed (P<0.001) between groups and was greatest in calves classified as docile (1.44 kg/day), followed by the restless group (1.41 kg/day) and the aggressive group (1.32 kg/day). Morbidity rate was highest (19.2%; P=0.009) in docile cattle, but did not differ between the restless and aggressive cattle (16.8 and 16.2%, respectively). Mortality rates were 1.09, 1.02 and 1.91%, respectively, for docile, restless and aggressive cattle.

Depression scoring was one criterion used by the researchers to assess BRD. They postulated that aggressive cattle were less likely to show depression when pen checkers were in the area, which may explain the numerically higher mortality rate in aggressive cattle while the morbidity rate was lower (P=0.009). It is also possible that caretakers had more difficulty removing aggressive cattle from the pen for examination and treatment in a timely manner. Economic return was $62.19 lower for aggressive cattle than for docile cattle in this study. Much of this difference in economic value was attributed to decreased death loss, increased average daily gain (ADG) and improved carcass quality grade in the docile cattle.

Market value differences between healthy and sick cattle

Iowa State University researchers (Schneider et al., Reference Schneider, Tait, Busby and Reecy2009) studied the effects of BRD on economically important traits in 5976 feedlot cattle. Incidence of BRD during the entire feeding period was 8.17% and total mortality was 1.43%, with 49% of deaths due to BRD. The decrease in growth performance and carcass value in the study resulted in a decrease of $23.23, $30.15 and $54.01 in cattle treated once, twice, or three times or more, respectively, when compared to cattle not requiring treatment. Cattle that did not develop BRD were more valuable (P<0.01).

The Texas A&M Ranch to Rail studies were conducted from 1992–1993 through 2000–2001 to allow producers to learn more about their calf crop and the factors influencing market value following weaning (McNeil, Reference McNeil1993, Reference McNeil1994, Reference McNeil1995, Reference McNeil1996, Reference McNeil1997, Reference McNeil1998, Reference McNeil1999, Reference McNeil2000, Reference McNeil2001). Steers owned by cooperating ranches were fed to harvest in commercial feed yards. Cattle were sold to the packers on a carcass value basis. Steers that remained healthy through the feeding period returned $49.55 to $151.18 per head more than steers that became sick and required treatment. The lower value of steers that became sick was due to medical costs, reduced performance, reduced carcass quality grade, increased death loss and increased culling prior to harvest. Based on arrival weight, steers that became sick were worth $8.65 to $26.48/45.45 kg less than steers that remained healthy. In the 2000–2001 report, medical costs for steers requiring treatment averaged $44.55 per head, and there was an additional $106.63 in ‘lost value’ ($151.18–44.55=$106.63). These examples clearly illustrate that the risk of BRD can have a dramatic impact on the market value of calves.