Abstract This review summarizes the effects of ractopamine hydrochloride (RAC) dose (5, 7.5, 10, and 20 mg/kg) on market weight pig welfare indicators. Ractopamine hydrochloride (trade name Paylean) is a β-adrenergic agonist that was initially approved in the U.S. in 1999 at doses of 5 to 20 mg/kg to improve feed efficiency and carcass leanness. However, anecdotal reports suggested that RAC increased the rate of non-ambulatory (fatigued and injured) pigs at U.S. packing plants. This led to the addition of a caution statement to the Paylean label, and a series of research studies investigating the effects of RAC on pig welfare. Early research indicated that: (1) regardless of RAC administration, fatigued (non-ambulatory, non-injured) pigs are in a state of metabolic acidosis; (2) aggressive handling increases stress responsiveness at 20 mg/kg RAC, while 5 mg/kg reduces stress responsiveness to aggressive handling. Given this information, dosage range for Paylean was changed in 2006 to 5 to 10 mg/kg in market weight pigs. Subsequent research on RAC demonstrated that: (1) RAC has minimal effects on mortality, lameness, and home pen behavior; (2) RAC fed pigs demonstrated inconsistent prevalence and intensity of aggressive behaviors; (3) RAC fed pigs may be more difficult to handle at doses above 5 mg/kg; and (4) RAC fed pigs may have increased stress responsiveness and higher rates of non-ambulatory pigs when subjected to aggressive handling, especially when 20 mg/kg of RAC is fed.

The current study evaluated 17 loads of cull beef cows transported in Canadian winter conditions to assess in-transit temperature and humidity, evaluation of events during loading and unloading, and animal condition and bruising. Regardless of the use of boards to block ventilation holes in trailers, temperatures were higher within trailers than at ambient locations during both travel and stationary periods (P < 0.01). Boarding was associated with smaller differences in trailer temperature, compared with ambient conditions, while the trailer was traveling at highway speeds versus when trailers were stationary (P < 0.01). Moisture levels within trailers were not different from ambient conditions when loads using boarding were traveling (P < 0.01), whereas loads without boarding had a larger difference (P < 0.01). The moisture within trailers relative to ambient conditions increased when trailers were stationary compared with traveling when boarding was used (P < 0.01). The majority of cattle transported were in good body condition (97.4% within BCS of 2 to 3.5) and had calm temperaments (96.7%). Although all comparisons were made, only the dog-house compartment had an increased risk of severe bruising compared with all other compartments (odds ratio [95% confidence interval]: 3.0 [1.6-5.5], 3.7 [2.16.4], 2.2 [1.3-3.7] and 3.8 [1.5-9.6] in comparison with the back, belly, deck, and nose compartments, respectively; P < 0.05). Increasing the duration of waiting to unload 30 min relative to a 1 h duration increased the odds of severe bruising by 1.18 times (95% confidence interval: 1.09-1.29; P < 0.01). Scoring systems that have been developed for auditing unloading of cattle had limited variation across loads at both loading and unloading. Pretransport assessment of animal condition using the American Meat Institute's compromised animal score was the only scoring system that was consistent with posttransport scores. We inferred from the temperature and humidity data in the current study that under commercial conditions, boarding may increase ventilation within trailers during travel and decrease ventilation during stationary periods. The current study provides the first indication that issues in Canadian cull cow transport may be related to pretransport animal condition and management of unloading.

Nineteen loads of commercial feeder cattle (BW 376 ± 39 kg, mean ± SD) transported for 18 ± 4.5 h in summer and winter seasons were used to collect data on internal temperature and humidity conditions in the deck and belly compartment of pot-bellied trailers and their relationship with shrink, cortisol, and morbidity. Measurements of temperature or humidity at ceiling or animal level did not vary with transportation factors. Temperature and humidity ratio was greater at animal-level than ambient conditions during nonhighway travel and stationary periods (P < 0.01). During the 3 time periods evaluated within journeys, there was a larger difference between animal-level and ambient conditions during the winter than during the summer (P < 0.01); however, this difference was not associated with other transport factors (P > 0.05). Evening loads (1700 and 2100 h) experienced more shrink in the summer than in the winter (11.2 ± 0.5 vs. 9.0 ± 0.5% of BW; P = 0.03). A 1°C increase in difference between average animal-level temperature in transit and the mean ambient temperature during the 10 d before transport was associated with a 0.11 ± 0.03% of BW increase in shrink (P < 0.01) and 0.006 ± 0.002 ng/mL increase in posttransport cortisol concentration (P = 0.05). Animal-level temperature-humidity index (THI) events (consecutive observations of THI greater than 78°F) were more likely to last for longer than 1 h when the trailer was stationary vs. traveling (mean = 1.8, confidence level 95% = 1.33, 2.52). During THI events at animal level, the disagreement with ambient temperature regarding THI classification was lower when the vehicle was traveling vs. stationary (95.5 ± 0.01% vs. 99.7 ± 0.002% of THI event in disagreement; P < 0.01) and was greatest in events less than 1 h (99.8 ± 0.0% vs. 91.7 ± 0.03% of THI event in disagreement; P < 0.01). The average magnitude of the difference during these events was 11.4 ± 7.6°F and was not affected by transportation factors (P > 0.05). Despite association between indicators of calf welfare and microclimate, all cattle arrived in good condition and there was 0.96% treatment rate within the first 30 d after arrival. Management and auditing decisions related to transportation of feeder cattle should consider the relationship between animal-level and ambient conditions and conditions before transportation. Under the commercial conditions of the current study, the transportation process did not appear to cause distress according to the dimensions of animal welfare that were assessed.

Measuring animal-level conditions during transit provides information regarding the true risk of environmental challenges to cattle welfare during transportation. However, due to constraints on placing loggers at the animal level, there is a need to identify appropriate proxy locations. The objective was to evaluate 8 distributions of ceiling-level loggers in the deck and belly compartments of pot-belly trailers for assessing animal-level temperature and humidity during 5 to 18 h commercial transportation of feeder cattle. Ambient conditions during transportation ranged from 3.6 to 45.2°C (20.3 ± 7.61°C, mean ± SD). When considering the entire journey, average differences between ceiling and animal-level temperatures were similar among logger layouts (P > 0.05). The uncertainty in the difference in temperature and humidity between locations was high relative to the magnitude of the difference between animal- and ceiling-level conditions. Single-logger layouts required larger adjustments to predict animal-level conditions within either compartment, during either the entire journey or when the trailer was stationary (P < 0.05). Within certain logger layouts, there were small but significant differences in the ability of regression equations to predict animal-level conditions that were associated with cattle weight and available space relative to body size. Furthermore, evaluation of logger layouts based solely on the entire journey without consideration of stationary periods did not adequately capture variability in layout performance. In conclusion, to adequately monitor animal-level temperature and humidity, 10 loggers distributed throughout the compartment was recommended over single-logger layouts within both the deck and belly compartments of pot-belly trailers transporting feeder cattle in warm weather.

Twenty-four commercial loads of beef calves (BW 300 ± 52 kg, mean ± SD) were evaluated for associations among transportation factors, in-transit microclimate, and calf welfare. Transport factors evaluated included vehicle speed, space allowance, compartment within trailer, and transit duration. Calves were transported for 7 h 44 min ± 4 h 15 min, with space allowances ranging from 0.56 to 1.17 m(2)/animal. Compartment within trailer, space allowance, and vehicle speed did not affect the difference between compartment ceiling-level and ambient temperatures during a 30-min period of steady-state microclimate. During the steady-state period, a 1°C increase in ambient temperature above the mean of 5.6°C was associated with a 0.62°C decrease in the difference between ceiling-level and ambient temperature (P < 0.01). Ceiling-level temperature and humidity during the first 400 min of transport could be predicted by ambient conditions and vehicle speed (pseudo-r(2) of 0.91 and 0.82 for temperature and humidity ratio; P < 0.01). Events when animal-level temperature-humidity index (THI) was classified as above the "danger" level lasted for 10.2 ± 4.1 consecutive minutes. Ambient and ceiling-level THI values were not classified as above "danger" for 90.0 and 84.9% of animal-level events. Ambient and ceiling-level THI were 5.0 ± 2.1 and 4.7 ± 2.0° Flower than animal-level THI during periods of disagreement, respectively. The majority of calves arrived in good condition and biochemical indicators of calf welfare were within reference ranges for healthy cattle. Within the study population, high pre-transport cortisol and hematocrit were associated with elevated post-transport values (P < 0.01). A 1% increase in shrink during the weaning to loading interval (24 or 48 h) decreased transportation shrink by 0.26 ± 0.04% when average animal-level temperature was greater than 5°C and decreased transportation shrink by 0.11 ± 0.04% when average animal-level temperature was less than 5°C (P < 0.01). We inferred that the study results support future investigation of the extension of in-transit microclimate as a risk factor for post-transport treatment for disease. The study also provided correction factors for estimating in-transit microclimate that could assist in evaluation of transportation management and decisions affecting profitability and calf welfare.

Two studies were conducted to evaluate a wireless rumination monitoring system (Hi-Tag; SCR Engineers Ltd., Netanya, Israel) for recording rumination in beef cattle. The system operates based on acoustics of rumination and has been used previously for monitoring rumination in both young and adult dairy cattle. Study 1 consisted of beef cattle in tie-stall housing with 72 observations for 4 cattle fed a high forage backgrounding diet and 47 observations for 3 cattle fed a high grain finishing diet. Study 2 consisted of 44 observations for 6 beef cattle fed a high forage diet in a loose-housing feedlot pen. Each observation consisted of the rumination time during a 2-h period as estimated by visual observations made by trained observers (inter-observer correlation r = 0.97) and the Hi-Tag system. The mean difference between visual and Hi-Tag rumination times was 9.8 ± 18.7 min/2 h. The rumination times from the Hi-Tag system were only moderately correlated with visual observations (r = 0.41, P < 0.001). The difference between visual and Hi-Tag rumination times was not correlated with head posture during the 2 h period (r = -0.02, P = 0.89). Physical and dietary differences between dairy and beef cattle may have resulted in the inaccuracy of the Hi-Tag system when used in beef cattle fed typical backgrounding and finishing diets. More work is required to improve the accuracy of this automated system for rumination monitoring before it can be used reliably with beef cattle.

Zero-grazing has been related to a higher incidence of lameness and other maladies, but continuous access to pasture can compromise dry matter intake (DMI) and milk production. The objective of the present study was to assess the effect of housing cows overnight on pasture on productivity and lameness. Fifty Holstein cows were balanced for calving date, bodyweight, parity and initial gait score and semi-randomly assigned to either continuous housing in a free-stall barn (CONTROL) or housing in a free-stall barn from the morning milking to 2000h and on pasture overnight (PASTURE). Treatments were applied from week −4 to week +8 relative to calving. Gait was scored every 4weeks beginning 4weeks before parturition to week 24 after calving whereas lying behavior was monitored continuously throughout the experiment. For 30 cows, DMI of the TMR was monitored continuously throughout the experiment. Gait score (1=not lame, 5=severely lame) did not differ between treatments (P=0.62) but primiparous cows had better gait compared to multiparous cows (2.0±0.1 vs. 2.5±0.1, P<0.001). Overall gait scores increased from 4weeks before calving to 4weeks after calving (increase=0.55±0.07, P<0.001), but did not change thereafter. Overnight pasture increased hoof net growth rate (2.2±0.5 vs. 1.0±0.5mm/month, P=0.03). There were no differences (P>0.10) between treatments in DMI from TMR with cows on average consuming 15.5±1.0kg/day in the 8weeks after calving. Most interestingly, milk production did not differ between the treatment groups with cows producing an average of 38.2±1.1kg/day over the 12weeks after calving. Daily lying time (578±18min/day) also did not differ between treatment groups. Parturition and parity are critical risk factors for lameness. Housing on pasture overnight is a practical way of increasing access to pasture without reducing TMR intake or milk production or increasing the risk of lameness.

Cows diagnosed with subclinical ketosis (SCK) after calving are at increased risk of developing other diseases and compromised reproductive performance. The objective of this study was to determine whether changes in feeding and social behaviors during the transition period were associated with SCK during the week after calving. Feeding behaviors of 101 Holstein dairy cows were monitored from 3 wk before to 3 wk after calving. Ten otherwise healthy animals were identified as having SCK by serum β-hydroxybutyrate levels ≥1,000 μmol/L taken during wk +1. These animals were matched by parity with 10 healthy animals. During the week before calving and the 2 wk after calving, animals with SCK had lower dry matter intake, had fewer visits to the feeder, and spent less time at the feeder than healthy animals. For every 10-min decrease in average daily time spent at the feeder during the week before calving, the risk of SCK increased by 1.9 times. During the same week, a 1-kg decrease in average daily dry matter intake increased the risk of SCK by 2.2 times. The largest increase in risk of SCK was associated with a 1-kg increase in the change in average daily intake from wk −2 to −1. During the week before calving, animals with SCK initiated fewer displacements at the feed bunk compared with animals that remained healthy after calving. The results of this study provide evidence that time spent feeding, dry matter intake, and social behavior play an important role in transition cow health. These results indicate that special consideration should be given to management and social factors that can negatively affect dry matter intake and feed bunk attendance during the transition period.