Applied Animal Ethology, 9 (1982/83) 359-365 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands
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Short Communication A NOTE ON NURSING TERMINATION AND RESTING BEHAVIOUR OF SUCKLING PIGLETS
J. CAROL PETHERICK The Scottish Farm Buildings Investigation Unit, Craibstone, Bucksburn, Scotland (Gt. Britain) (Accepted for publication
Aberdeen,
31 March 1982)
ABSTRACT Petherick, J.C., 1983. A note on nursing termination piglets. Appl. Anim. Ethol., 9: 359-365.
and resting behaviour of suckling
Observations were carried out on 8 Large White X Landrace sows and their litters housed in either large straw-bedded pens, or conventional farrowing pens. The animals were observed for periods during the 8 days following parturition. Sows in the straw-bedded pens had built nests into which the piglets were born. Sows and piglets did not rest outside the nest for at least 3 days after parturition and piglets rested nearer to the sow on Days l-4 than on Days 5-8. Nursings were terminated either by the sow continuing to lie with the udder exposed or making the udder inaccessible by rolling on to the sternum or standing. Sows rolled on to the sternum less often on Days l-3 than on Days 6-8 (difference significant at P < 0.01 in straw-bedded pens and at P < 0.05 in farrowing pens). Of the 198 sucklings observed, only once did piglets move away from the sow when the udder was accessible. On Days l-4, piglets in the straw-bedded pens remained by the sow after suckling, regardless of the way in which the nursing was terminated. Throughout the study, piglets in farrowing pens usually moved away to the creep area after suckling. It is suggested that whilst providing a heat lamp may encourage piglets to rest away from the sow, a more important factor is the accessibility of the udder to the piglets.
INTRODUCTION
One consequence of the intensification of pig production has been the reduction of the pig’s living space. It is important to specify the animal’s space requirements, as insufficient space may depress rate of live-weight gain or feed conversion (Heitman et al., 1961; Gehlbach et al., 1966; Bryant, 1970), yet excessive space is wasteful of building materials and costly. The total space allocation in contemporary pens is governed by the size of the resting area (Brambell, 1965 para 106; Sainsbury, 1967) which is, in turn, affected by the thermal environment (Mount, 1968,1979). The present study investigated the resting behaviour of young piglets to
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gain information on the development of the mechanism underlying the selection of the resting area. The newborn pig is normally exposed to ambient temperatures well below that of its own body. Bedding, heat lamps, litter mates and the sow are all potentially beneficial modifiers of the thermal environment, and would thus be expected to influence a piglet’s selection of a resting site. METHOD
Subjects Eight Large White X Landrace sows in their second or third parity, with litters of a minimum of 8 piglets, were used in the experiment. Housing Four sows were housed individually in large pens (Fig. 1) which were bedded with approximately 180 kg of straw. Additional straw was not added, nor were the pens cleaned out. The pens were in a large unheated
I Feed trough Raised concrete phnth 150 mm high
Sow nipple drinker Piglet bowl drinkerunder
1.25 m high walls /
A’
A’
-7 Gate
‘_
Fig. 1. Plan diagram of straw-bedded
\
I
pen.
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0,
Creep lamp
-I
4
0.55 $1 high walls
E conf inec
2m
I*
rti
P Creep lamp
sow confined
in this
ate8
AL
Fig. 2. Plan diagrams of farrowing pens.
building (air temperature O-6%) with continuous lighting at 128-148 lux for the first 4 days after parturition. Thereafter, light was provided from 09.00 h to 17.00 h. The other 4 sows were housed in unbedded conventional farrowing pens (Fig. 2), though availability of accomodation dictated that 2 different types were used. These pens were in a heated farrowing house, air temperatures being 18 + 2°C and lighting at 105-240 lux for 9 h each day between 08.00 h and 19.00 h. Observations Sows and litters were observed for 7.5 h each day on Days 1 and 2 after parturition and for 4 h a day on Days 3-8 inclusive. All observations were made between 07.00 h and 18.00 h. Observations of the animals in strawbedded pens were made from a platform 1 m from the gated wall, the observer being seated at a height of 1.9 m. In the farrowing house, the observer sat at a height of 1.4 m on a platform 0.5 m from the rear of the pen. In neither situation was the observer concealed from the animals, but care was taken not to disturb them. At the end of each nursing it was recorded whether sows continued to lie with the udder exposed, or rolled on to the sternum or stood. A note was also made whether the litter moved away from, or stayed by, the sows. The
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litter was defined to have moved away if at least 75% of them had done so within 2 min of the end of milk letdown (as determined by the cessation of rapid sucking movements by the piglets). The animals in the straw-bedded pens were continuously video-recorded on Days l-4 and for 7.5 h each day on Days 5-8. A plan of the pen was sows
PIGLETS
??
% resting sites wrthin nest 75.5-84.7
??
* % resting sites within nest 67.1-70.0
??
* % resting sites within nest 44.0-78.6
??
* % resting sites within nest 39.3-58.0
* Some
resting
sites
have been within
are in sections
crossed
??
by the nest
or outside the nest. Percentages
boundary
which
% resting sites within nest 82.4-98.3
% resting sites within nest 64.1-67.1
% resting sites within nest 76.3-96.8
% resting sites within nest 25.4-53.3
means they could
inclusive and exclusive of these numbers
are given.
Fig. 3. Distribution of resting sites in straw-bedded pens.
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divided into 16 sections and a record made of the number of times the animals rested in each section. When the sow and litter rested at the same time, the distance between them (from the centre of the sow’s body to the centre of the group of piglets) was scaled from the video monitor. Resting was defined for the sow as when she was lying and for the litter when at least 75% of them were either lying or sucking/massaging the sow’s udder. RESULTS
Prior to parturition, the sows housed in straw-bedded pens constructed nests, from straw, into which the piglets were born. The sows and piglets did not rest outside the nest for at least 3 days after parturition. Figure 3 shows the distribution of resting sites in the straw-bedded pens. The average distance between the sow and litter when both were resting was 1.6 m on Days l-3 and 2.2 m on Days 6-8. This difference approached significance at the 5% level. At the end of nursing, the sows made the udder inaccessible by rolling on to the sternum in 21.3% of cases on Days l-3 and 53.8% of cases on Days 6-8 (difference significant at P < 0.01). For sows in farrowing pens, this was 10.2% on Days l-3 and 34.1% on Days 6-8 (difference significant at P< 0.05). Of the 198 nursings terminated by the sow continuing to lie with the udder exposed, on only one occasion did the piglets move away. If the udder was made inaccessible, within 2 min of the end of milk let-down the litter moved away in 55 of the 81 cases. Figure 4 shows that in the straw-bedded STRAW BEDDED
PENS
FARROWING
PENS
100
7 Stay by sow
90
i
80
z
70 r
8
Day number n
3
Day number 0
Move away from sow
Fig. 4. Response of piglets to sow terminating sucklings by rolling onto her sternum.
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pens, the piglets usually stayed by the sow on Days l-4, regardless of the way in which nursing was terminated. On subsequent days, they usually moved away. In the farrowing pens, the piglets usually moved away from the sow to the creep area after suckling, with the exception of Day 5. DISCUSSION
It has been suggested that 2 factors determine a piglet’s behaviour immediately after birth, (a) a need for warmth and (b) a need to suck (Pflug, 1976; Van Putten and Dammers, 1976). The sow’s udder is, therefore, a very attractive stimulus to the young pig. A nest, largely as a result of the presence of the mother and other young, is thermally more comfortable than the surrounding area (Gundlach, 1968; Rosenblatt, 1976) and would, therefore, also be attractive to the piglet. In the present study, a piglet in the straw-bedded pens was dependent upon the sow, litter mates and nest for warmth, and would thus be expected to remain close to them. This is substantiated by the exclusive use of the nest for resting on Days 1-3 and the litter staying by the sow after suckling on Days l-4. In commercial pig production, supplementary heat is often provided for piglets by means of a lamp suspended over the creep area. This source of warmth is said to encourage the young to lie away from the sow, thus reducing the chance of crushing when the sow moves (Signoret et al., 1975; Titterington and Fraser, 1975; English et al., 1978). The results of the present study support this theory to a degree, but the piglets only moved away to the heated creep area if the sow made her udder inaccessible. After nursing, sows in both housing conditions made the udder increasingly inaccessible as the piglets got older, which is in agreement with Whatson and Bertram (1980). Therefore, as would be expected, the piglets moved away from the sows after suckling more often on Days 5--S than on Days l-4. CONCLUSION
This work indicates that the resting sites of newborn piglets is influenced by the way the sow terminates nursings. After suckling, piglets will remain by the sow unless she makes the udder inaccessible. Nursing termination may thus be an important study area in reducing piglet deaths by crushing. ACKNOWLEDGEMENTS
This research Council (U.K.). Edinburgh) for animals and the
was supported by a grant from the Agricultural Research I thank Mr. E.A. Hunter (A.R.C. Unit of Statistics, his advice on data analysis, Mr. E.H. Auton for supplying the staff of S.F.B.I.U. for their assistance and encouragement.
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