Salbutamol has potential for use as a
repartioning agent in swine. The aims of this experiment
were to determine effects of salbutamol on behavior
and physiology of finishing pigs. The study used
192 pigs (88.8 ± 0.9 kg of BW) housed in groups of 6
in 32 pens and assigned to 1 of 4 treatments: 1) control—
0 mg/kg of salbutamol, 2) 2R—control diet with
2 mg/kg of the pure R-enantiomer of salbutamol, 3)
4R—control diet with 4 mg/kg of pure R-salbutamol, or
4) 8RS—control diet with 8 mg/kg of a 50:50 mixture
of the R- and S-enantiomers. All diets were offered ad
libitum for 4 wk. Salbutamol diets were replaced with
control diets 24 to 48 h before slaughter. Behavioral
responses to handling during weighing were recorded
immediately before assignment to the treatments (wk
0) and at weekly intervals over the next 4-wk period.
Behavioral and heart rate (HR) responses to a 10-min
human presence test in the home pen were measured
during wk 0, wk 1, and wk 3. Heart rate responses to
a 36-min transportation were recorded. One pig from
each pen had blood collected 4 times: during wk 0, 2, 4,
and at exsanguination. Blood was analyzed for NEFA,
creatine kinase, glucose, lactate, blood urea nitrogen,
ammonia, insulin, cortisol, norepinephrine, and epinephrine.
Data were analyzed using PROC GLM of
SAS, with pen as the experimental unit. Treatment
had no effect on time spent lying laterally, overall activity,
or time spent alert. Treatment had no effect on
handling measures (P > 0.05) or on behavioral responses
to human presence (P > 0.05), with all pigs willing
to spend similar amounts of time close to and touching
the human. However, during the human presence
test in wk 1 and wk 3, control pigs had HR around 10
peats per minute less (P < 0.05) than pigs in the other 3 treatments. During transport, overall HR were similar across treatments (P > 0.05). However, at certain 1-min
time points, control pigs had greater HR than salbutamol-
treated pigs (P < 0.05). There were no treatment differences in lactate, epinephrine, or norepinephrine concentrations at any point. During wk 4, control pigs had less creatine kinase (P < 0.02) and greater blood urea nitrogen (P < 0.005) compared with pigs fed all the salbutamol treatments. The home pen behavior, handling, human presence test, and transport results indicate that salbutamol-treated pigs do not show marked differences in home pen time budgets and behavioral and HR responses to handling and transportation compared with control pigs. Thus, salbutamol did not have a negative effect on finishing pig well-being during this study.