




































In ternationa l
Scholars
Journa ls

 

African Journal of Pig Farming ISSN 2375-0731 Vol. 5 (6), pp. 001-006, June, 2017. Available online at 
www.internationalscholarsjournals.org © International Scholars Journals 

 

Author(s) retain the copyright of this article. 

 

Full Length Research Paper 

 

Effects of road transportation on excitability 
scores of pigs administered with ascorbic acid 

during the hot-dry season 

 
Olayinka Oluwafemi Asala1*, Joseph Olusegun Ayo2, Adeshina Yahaya Adenkola3 

and Ndazo Salka Minka4
 

 
1
National Veterinary Research Institute, P. M. B. 01, Vom, Plateau State, Nigeria. 

2
Department of Veterinary Physiology and Pharmacology, Ahmadu Bello University, Zaria, Nigeria. 

3
Department of Veterinary Physiology and Pharmacology, University of Agriculture, Makurdi, Nigeria. 

4
College of Agriculture and Animal Science, Ahmadu Bello University, Mando, Kaduna, Nigeria. 

 
Accepted 23 November, 2016 

 
This study was carried out in order to determine the effect of eight-hour road transportation on the excitability scores 
of pigs administered ascorbic acid (AA) during the hot-dry season in Northern Nigeria. Thirteen experimental pigs 
were administered with AA orally at 100 mg/kg, while ten control pigs were given only distilled water orally. 
Excitability score of each pig was determined 30 min before and immediately after transportation by a single ‘blind’ 
observer during weighing. An excitability score of 4 indicated the highest excitability. Percent excitability of 
experimental and control pigs with each score was also determined. Post-transportation, an increase in the 
percentage of experimental pigs with excitability score of 4 was recorded (38.5 to 69.2%), while a decrease was 
obtained in the control pigs (40.0 to 10%). Road transportation decreased the excitability scores and percent 
excitability in control pigs with high scores. In conclusion, administration of AA increased the nervous excitability of 
pigs transported by road during the hot-dry season in northern Nigeria. 

 

Key words: Pigs, road transportation, stress, excitability scores, ascorbic acid, hot-dry season. 

 
INTRODUCTION 

 
It has been established that road transportation has 
adverse effects on health and productivity of pigs as a 
result of vibration (Perremans et al., 2001), regrouping of 
animals leading to fights (Wellock et al., 2003) and other 
harmful effects (Ishiwata et al., 2004). The negative 
effects of road transportation on pigs are further 
aggravated by concomitant subjection to heat stress, 
occurring when animals are transported during periods of 
high ambient temperature (AT) and relative humidity (RH) 
(Ayo et al., 1998; Renaudeau et al., 2007), characteristic 
of the hot-dry season. The hot-dry season, also charac-
terized by long duration of sunshine, has been shown to 
be thermally stressful to animals (Ayo et al., 1998; 
Sinkalu et al., 2008). The welfare of these animals can be  
 
 

 
*Corresponding author. E-mail: ofcasala@yahoo.com. Tel: 
+2348065690278 

 
 
 

 
partially assessed by objective indicators of stress 
(William et al., 2004).  

Livestock experience a variety of stressors provoked by 
abrupt social, nutritional and environmental changes, 
which induce homeostatic responses, modify behaviour 
and growth and leads to loss of performance (Niekamp et 
al., 2007; Obernier and Baldwin, 2006; Pineiro et al., 
2007). Transportation stress has been shown to activate 
the hypothalamo-pituitary-adrenal axis, releasing gluco-
corticoids from the adrenal cortex (Yoshioka et al., 2004); 
thus resulting in decreased immunity and appetite (Brown 
et al., 1999; Renaudeau et al., 2007), hyperthermia 
(Lambooij, 2000; Minka and Ayo, 2007) and decrease in 
nervous excitability (Ayo et al., 2006). Stress has been 
demonstrated to induce generation of free radicals in 
large quantities in the body such that the body‟s anti-
oxidant defence mechanisms are overwhelmed or 
exhausted (Iwolakun et al., 2004; Meerson, 1986; Tauler 
et al., 2003). 



 
 
 

 

The welfare of transported pigs and pork quality during 
slaughter of pigs have been shown to be improved by the 
administration of antioxidant vitamins before transportation 
(Peeters et al., 2005; 2006). Although, it has been 
demonstrated that pigs are capable of synthesizing ascorbic 
acid (AA), vitamin C, evidences have shown that during 
stress, the rate of the synthesis is grossly inadequate and 
plasma AA decreases considerably (De Rodas et al., 1998).  
AA is a water-soluble antioxidant vitamin, non-toxic, sus-
tainable and readily metabolized by the body of most 
domestic animals and humans (Hickey et al., 2008; 
Padayatty et al., 2003), when administered orally its 
absorption takes about 30 min (Hickey et al., 2008; 
Pardue et al., 1984; Tsao, 1997). AA has been demon-
strated to ameliorate heat and transport stresses in 
pullets (Ayo et al., 2005; Minka and Ayo, 2008) and 
increase nervous excitability in transported goats (Ayo et 
al., 2006).  

The aim of the present study was to determine the 
effect of eight-hour road transportation on the excitability 
of local pigs administered with AA during the hot-dry 
season in northern Nigeria. 

 

MATERIALS AND METHODS 
 
Experimental site 
 
The experiment was conducted at the animal research pen of the 

Faculty of Veterinary Medicine, Ahmadu Bello University, Zaria (11
o
 

10′ N, 07
o
 38′ E), located in the Northern Guinea Savannah zone of 

Nigeria. Transportation of the pigs was carried out during the hot-

dry season in May, 2007 from Zaria (11
o
 10′ N, 07

o
 38′ E), to 

Pambegua (10
o
 4' N, 08

o
 16' E) and from Pambegua back to Zaria, 

covering a total distance of 400 km. The zone is characterized by 
three major seasons, namely: The hot-dry, rainy and harmattan 
seasons. Of the three seasons, the harmattan has been described 
as the most thermally stressful to livestock (Ayo et al., 1996; Igono 
et al., 1982). This period marks the peak of the hot-dry season, just 
before the onset of the rainy season in the zone. 

 

Animals and management 
 
Twenty three (23), apparently, healthy adult local pigs comprising 
non-castrated males, non-pregnant and non-cycling females of 
about one-year-old and weighing between 40 - 50 kg served as 
subjects. The pigs were purchased from Samaru, Zaria four weeks 
before commencement of the experiment. They were housed in the 
animal pen of the Faculty of Veterinary Medicine, Ahmadu Bello 
University, Zaria. The pen was made of concrete floor, cement 
block wall and roof and consisted of two chambers. The pigs moved 
freely within the pen. They were managed intensively and fed a 
standard compounded feed, consisting of a mixture of maize bran 
and rice husk. Water was given ad libitum. The pigs were pre-
conditioned for two weeks before commencement of the experiment 
and they were dewormed using piperazine hydrochloride (Ever-
chem, China) at a dose of 110 mg/kg orally. They were also treated 

against ectoparasites using Ivermectin
R

 (Merial, France) at a dose 
of 0.05 mg/kg subcutaneously. 

 

Experimental design 
 
After  the  two-week  period of pre-conditioning, each  pig was 

  
  

 
 

 
identified by a numbered neck collar. A week to the day of 
commencement of transportation, pigs were assigned experimental 
(Group I) and control (Group II) groups consisting of 13 and 10 pigs 
respectively. Neck collars already numbered (1- 23) were put in a 
bag and picked „blindly‟ one at a time without replacement. Each 
collar picked was placed on the neck of individual pig caught at 
random. Animals with collar numbers 1 to 13 were classified as 
experimental (Group I) while those with collar numbers 14 to 23 
were classified as control (Group II). On the day of transportation, 
30 min before transportation, pigs in group I, which served as 
experimental animals were administered orally with 100 mg/kg 
body weight of AA (ARCHY Pharmaceuticals, Nigeria; NAFDAC no: 
04-5270, Batch no:VCW 7024) dissolved in 20 ml of water. The 10 
pigs in group II which served as control were administered with 20 
ml of distilled water, each orally. Feed and water were withdrawn 
12 h before and throughout the journey period, which lasted eight 
hours. All the pigs were transported on asphalt roads at an average 
speed of 50 km/h. After the completion of the journey, the pigs were 
unloaded at the same spot from where they were loaded 
previously. Feed and water were then provided ad libitum. 

 

Vehicle design and loading 
 
A standard Bedford van (made in England) and popularly used in 
the Northern Guinea Savannah zone of Nigeria for transportation of 
pigs was used for the journey. The body of the vehicle was made of 
aluminium and the floor of steel. The inner compartment of the 
vehicle measured 5.5 m x 1.5 m. The side walls of the body of the 
vehicle to a height of 1.1 m was made of aluminium and above 
which had windows for ventilation. The vehicle had at its rear end a 
twin door with a rear wind screen. The upper side walls and roof 
are also covered with aluminium. The floor of the vehicle was 
covered with dry straw and covered with a thick rubber mat for 
secure footing. Transportation procedures were carried out 
according to the guidelines governing animal transport welfare by 
road as des-cribed by Knowles et al. (1998). Briefly, pigs were 
loaded indivi-dually by two persons in a relatively calm condition. 
One person easily caught a pig at a time and carried it to the other 
person, who already was in the vehicle. The pigs were stocked at a 

rate of 0.3 m
2
/pig. 

 

Measurement of meteorological parameters 
 
Meteorological parameters of ambient temperature (AT) and 
relative humidity (RH) were recorded using the wet and dry-bulb 
thermometer (Ellab Inc, U.S.A.) at the experimental site just before 
loading the pigs into the vehicle, during transportation and 
immediately after unloading. 

 

Excitability score and live-weight of pigs 
 
Excitability scores were recorded while weighing the pigs according to 

the adapted methods described by Ayo et al. (2006), Kannan et al. 

(2002) and Voisinet et al. (1997). Briefly, liveweights of pigs were 

measured using the conventional bathroom scale (Philip Harris, 

England). An individual whose weight was first recorded on the scale 

remained standing on the weigh scale, while another person restrained 

the pig and handed it to the person on the scale. The reading on the 

scale was taken again and the weight of the person on the scale was 

subtracted from the second reading to give the weight of the pig. A 

score of 1 to 4 was allocated to each pig by a single “blind” observer, 

with higher scores representing higher excitability. A score of 1 was 

allocated to a pig that was calm, with little movement during weighing. A 

score of 2 was allocated to a pig that occasionally shook itself in an 

attempt to escape. A score of 3 was assigned to a pig that 



 
 
 

 
Table 1. Ambient temperature and relative humidity at the experimental site for five days before transportation of pigs. 

 

Hour Ambient temperature (
o
C) Relative humidity (%) 

 Dry-bulb Maximum Minimum Mean ± SEM Maximum Minimum 

06:00 23.5 ± 0.4 24.0 23.5 73.0 ± 8.0 95 57 

13:00 37.0 ± 1.0 39.0 33.0 55.8 ± 6.0 78 43 

18:00 35.6 ± 1.0 39.0 33.0 71.2 ± 6.0 82 50 

Overall mean ± SEM 32.0 ± 4.2 34.0 ± 5.0 29.8 ± 3.1 66.7 ± 5.4 86.6 ± 6.7 50.0 ± 4.0 
 

 
Table 2. Ambient temperature and relative humidity inside the  
vehicle during the journey period. 

 

Journey Dry-bulb Relative 

duration (h) temperarure (
o
C) humidity (%) 

0.5 30.5 68.0 

2 33.0 57.0 

4 37.0 53.0 

6 36.5 40.0 

8 39.0 71 

Mean ± SEM 34.0 ± 1.7 59.3 ± 4.7 
 

 
Table 3. Meteorological data from the experimental site three days post-transportation of pigs. 

 

Hour Ambient temperature (
o

C) Relative humidity (%) 
 Dry-bulb Maximum Minimum Mean±SEM Maximum Minimum 

06:00 22.0 ± 0.5 23.0 21.0 80.3 ± 4.9 89.0 72.0 
13:00 29.6 ± 0.3 30.0 29.0 56.6 ± 1.6 60.0 55.0 
18:00 28.0 ± 3.0 31.0 25.0 61.5 ± 11.5 73.0 50.0 

Overall mean ± SEM 26.5 ± 2.3 28.0 ± 2.5 25.0 ± 2.3 66.1 ± 7.2 74.0 ± 8.3 59.0 ± 6.6 
 

 
continuously attempted to free itself by shaking. A score of 4 was 
assigned to a pig that struggled violently throughout the weighing 
time. Excitability scores and live-weight were measured just before 
loading and upon completion of tran-sportation, immediately after 
unloading of pigs. 

 

Statistical analysis 
 
Meteorological data obtained were expressed as mean ± standard 
error of the mean (mean ± SEM) and were subjected to student‟s t-
test. Percentages of animals with each excitability score in experi-
mental and control groups were calculated and the relationship 
between excitability score and percent excitability for each group 
was determined using Pearson‟s correlation coefficient. P values < 
0.05 were considered significant. 
 

 

RESULTS 

 

Meteorological data 

 

The meteorological data from the study period are shown 
in Tables 1 - 3. Five days before transportation, the AT 
recorded at the experimental site ranged between the 
maximum value of 39.0°C and the minimum value of 

 

 

23.5°C, with a wide range of 16.5°C. The RH at the 
experimental site before transportation ranged between 
43 - 95%. The dry-bulb temperature (DBT) was highest at 
13:00 h with mean value of 37 ± 1.0°C (Table 1). During 
the journey period and inside the vehicle, the DBT rose 
gradually from 30.5°C within the first 30 min of the 

journey and attained a peak value of 39.0°C at the 8
th

 h, 
when the journey was completed. During the journey, the 
mean DBT value inside the vehicle was 34.0 ± 1.7°C, 
while the RH ranged between 40 - 71%, with a mean 
value of 59.3 ± 4.7%. Thus, the RH had a wide range of 
29% during the journey period (Table 2).  

The meteorological data during the post-transportation 
period are presented in Table 3. The minimum and maxi-
mum AT values were 21 and 31°C, respectively, while 
the mean DBT values at the experimental site ranged 
from 22.0 ± 0.5°C to 29.6 ± 0.3°C. The maximum and 
minimum RH values were 89 and 50%, respectively. 

 

Excitability scores of pigs pre-transportation and 
post-transportation 

 

The  excitability  score  of  1 was recorded  in 15.0 and 



 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

P
e
rc

e
n
t 
e
x
c
it
a
b
ili

ty
 (

%
) 

 
 
 
 
 

 
80  
 
 
 
70  
 
 
 
60 
 
 

 
50 
 
 

 
40  
 
 
 
30  
 
 
 
20  
 
 
 
10 
 
 

 
0 

  
1 2 3 4 

 
Excitability scores 

  
  

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 Pre-transportation  

Post-transportation 

 

 
Figure 1. Excitability score (%) of experimental (administered with ascorbic acid) pigs (n=13) pre and post-transportation. 

 

 

30.0% of experimental and control pigs, respectively just 
before loading the pigs into the vehicle. However, imme-
diately after eight-hour transportation, none of the experi-
mental pigs showed excitability score of 1, but 70.0% of 
the control pigs showed an excitability score of 1. The 
excitability score of 2 was recorded in 7.7% of experi-
mental pigs pre-transportation, but at post-transportation, 
the value increased to 23.0%. In the control pigs, the 
value of 20.0% was recorded for pigs with excitability of 2 
for both pre- and post-transportation.  

The excitability score of 3 was recorded in 38.5% of the 
experimental pigs and 10.0% of the control pigs just 
before loading; but immediately after the 8-h journey, the 
values decreased to 7.7% and to 0.0% in the experi-
mental and control pigs, respectively. Before transporta-
tion, percent values of excitability score of 4 recorded in 
experimental and control pigs were 38.5 and 40.0%, 
respectively. Post-transportation, the percent excitability 
in the experimental pigs rose to 69.2%, while in control 
pigs, the value decreased to 10.0%. 

 
 

 

The excitability score and percent excitability in pigs 
pre-transportation were strongly correlated (r = 0.8179; P  
< 0.001) in experimental pigs, but in control animals the 

relationships were weak (r = 0.2000, P > 0.05). Imme-diately 

after transportation, the excitability scores and percentage 

excitability were significant (P < 0.001) and positively 

correlated (r = 0-795, P < 0.001) in experimental, but 

negative and significant in control pigs (r = -0.833, P 

< 0.001) (Figures 1 and 2). 

 

DISCUSSION 
 
The results of the excitability scores in control pigs 
showed that road transportation for eight hours in the 
zone, with concomitant effect of high AT and RH during 
the hot- dry season, induced depression. This was 
evident in the high post-transportation percent excitability 
of 70.0% obtained in control pigs with an excitability 
score of 1 compared to the corresponding value of 30.0% 
recorded pre-transportation. And a percentage decrease 



 
 
 
 

 
 80 

 

 70 
 

 60 
 

%
e
xc

ita
b

ili
ty

 

50 
 

40  
  

 30 
  

 
 

 
20 

 
 

 
10 

 
 

 
0  

1 2 3 4 
 

Figure 2. Excitability score (%) of control pigs (n =10) pre and post-transportation. 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 Pre-transportation 

 
 Post-transportation 

 

 

in the control pigs with an excitability score of 4 post-
transportation. The results obtained from the study further 
confirm the previous findings in pigs (Brown et al., 1999) 
and goats (Ayo et al., 2006) that road transportation 
depresses the nervous system immediately after the 
journey in animals not administered with AA.  

The fact that the administration of AA before road 
transportation of pigs resulted in a decrease in the 
percentage of animals that were depressed (that is, those 
with the excitability score of 1) and an increase in the 
percentage of pigs that were excited (that is, those with 
excitability score of 4) after the journey demonstrated that  
AA activated the nervous system in experimental pigs by 
reverting the depression, observed in control pigs, back 
to excitation. The finding is in agreement with the 
previous result obtained by Ayo et al. (2006) that AA 
activates the nervous system in goats transported by 
road. Although, the mechanism of action of AA was not 
investigated in the present study, it has been shown that 
AA potentiate gamma amino butyric acid and inhibits the 
release of cortisol. AA was also shown to be involved in 

 

 

the synthesis of norepinephrine and 5-hydroxytryptamine 
which activate brain function and mood (Balz, 2003). 
However, the fact that AA is found in high concentration 
in synaptic vesicles and the evidence that it could be 
released into the extracelluar space by neuronal activity 
suggested that AA might be a neurotransmitter, thus may 
cause excitation of the nervous system (Karanth et al., 
2000).  

The results obtained from the present study demon-
strated that AA administration just before road transporta-
tion of pigs was beneficial in reducing stress induced by 
the transportation and heat stress caused by high AT and 
RH experienced during the hot-dry season in northern 
Nigeria. The results also confirmed the previous report 
that AA increases resistance to environmental stress 
(Tauler et al., 2003). The results of the present study, for 
the first time, demonstrated that road transportation for 
eight hours during the hot-dry season in the zone is 
stressful and that AA administration abolished the fatigue 
and depression of the nervous system caused by the 
journey. 



 
 
 

 

Conclusion 

 

In conclusion, transportation of pigs by road for eight 
hours in the Northern Guinea Savannah zone of Nigeria 
induces depression and AA administration increases 
nervous excitability in the transported pigs. 
 

 
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