D.T. Beatty

Validating the Use of Qualitative Behavioral Assessment as a Measure of the Welfare of Sheep During Transport

We tested the application of qualitative behavioral assessment (QBA) as a welfare assessment tool. Sheep were exposed to road transport treatments, and behavioral expressions were compared between experimental treatments and validated by correlation with physiological measures. We compared journeys differing in ventilation (closed vs. open-sided trailer), flooring (grip vs. nongrip flooring), and driving styles (stop–start vs. continuous driving). Blood samples were collected immediately before loading and after unloading; heart rate and core body temperatures were recorded continuously. Continuous video footage was edited to show individual sheep to observers for QBA using free-choice profiling (observers used their own descriptive terms). There was significant consensus in observers’ scores for the sheep in each experiment (p < .001). Observers distinguished between sheep exposed to flooring (p = .014) or driving-style (p = .005) treatments, but not between ventilation treatments. QBA scores were compared (p < .05) with plasma leptin, glucose, and insulin-like growth factor-1 concentrations; white blood cell profiles; red blood cell counts; hematocrit; body temperatures; and heart rate variability. Observer assessments reflected treatment differences, and correlations between behavioral expression and physiological responses were found.

Grain feeding increases core body temperature of beef cattle

The core body temperature and post slaughter loin temperatures of steers fed on grass pasture was compared with those of steers fed a grain-based feedlot diet. The feeding treatments were grass for 300 days (Grass), grass for 150 days then feedlot for 150 days (Short Feedlot) and feedlot for 300 days (Long Feedlot). Temperature telemeters were inserted under the peritoneum of the steers and temperature measured at intervals of 1 h for the 300 days, and then at intervals of 1 min for the 48-h period before slaughter. The pH and temperature decline post mortem was also measured. The carcasses of the feedlot steers were heavier and fatter than those from the Grass-fed steers. The core body temperature of the steers from the feedlot treatments was 0.3–0.4°C higher than for the Grass treatment at the time of slaughter. The loin temperature was higher in the feedlot treatments than the Grass treatment at all times measured post mortem as was the temperature at pH 6. Feedlotting can increase the likelihood of ‘high rigor temperature’ conditions of high temperature and low pH occurring in beef carcasses, due to an increase in core body temperature before slaughter, a decrease in the rate of cooling and an increase in the rate of pH decline post mortem. These effects are possibly due to a combination of a direct effect of feed type on body temperature as well as indirect effects on bodyweight and condition score.

A preliminary study into the use of ‘heat pipes’ to prevent high rigor temperature in beef carcasses by increasing cooling rate

Three experiments were conducted to investigate the use of a custom-made heat pipe to reduce muscle temperature in beef carcasses during the initial part of the refrigeration period post slaughter. The effects of muscle depth (Experiment 1) and radial distance from a heat pipe (Experiment 2) were investigated initially. Then the use of multiple heat pipes was compared with no heat pipes for the loin and hind leg regions of a carcass (Experiment 3). All three experiments were conducted at a commercial beef abattoir in Western Australia. Without heat pipes, the time taken for the temperature to fall to 35°C in the hind leg was 10, 90 and 300 min for depths of 25, 50 and 100 mm from the surface, respectively. Temperature increased with radial distance from a heat pipe and the relative differences in temperature between different positions increased with time. Temperatures 110 min after the commencement of cooling were 35.7, 36.8 and 38.3°C for 20, 40 and 80 mm from the heat pipe, compared with 39.8°C without the pipe. The loin cooled faster than the rump, which cooled faster than the leg. Heat pipes increased the rate of temperature loss in the leg but not the loin. The time taken for the leg temperature to reach 35°C, measured at a depth of 100 mm, reduced from 150 to 76 min. These experiments confirm that heat pipes containing methanol could be used to increase the rate of heat loss from leg muscles in beef carcasses. Further work is required to determine if the magnitude of these increases in cooling rate would improve eating quality for large carcasses.

Electrolyte supplementation of live export cattle to the Middle East

Eighty Bos taurus crossbred steers sourced from southern Western Australia were monitored to assess the efficacy of electrolyte supplementation on board a livestock vessel travelling to the Middle East during the northern hemisphere summer. Electrolytes (1.8 g/L NaHCO3 and 3.5 g/L KCl) were added to the drinking water of treatment steers (n=39) allocated to three pens on the starboard side of the ship. Control steers (n=40) were allocated to three pens on the port side of the ship. The combined area of the three treatment and three control pens was 61.1 and 63.6 m2 respectively, giving a stocking density of 1.57 and 1.55 m2 per steer, respectively. Steerswere loaded in Fremantle,Western Australia and given 3 days to acclimatise to on-board conditions before being weighed (day 1), after which electrolyte supplementation beganwhile the vessel docked at Port Headland,Western Australia. Feed andwaterwere available ad libitum throughout the experiment. Steerswereweighed again on day 18, before discharge in the Middle East. During electrolyte supplementation, wet bulb temperature ranged from 21.3 (day 2) to 31.8°C (day 18). Over the last 3 days of the experiment, wet bulb temperature ranged from 29.0 to 31.8°C with no diurnal variation or night-time cooling. No open-mouth panting was recorded in either group and although animals encountered periods of high heat and humidity (as indicated by increased respiratory rates), the steers were not considered clinically heat stressed during the experiment. After 18 days of electrolyte supplementation, treatment steers had a 2.9 ± 1.7% liveweight advantage compared with control steers (P < 0.001). Urine was collected on days 8 and 16 of the experiment and treatment steers maintained a higher urine pH compared with control steers on both days (day 8; 8.6 v. 8.2 and day 16; 8.2 v. 7.9; P < 0.01). Liveweight advantages and improved regulation of acid-base balance may provide welfare and economic benefits to the live export industry.