RESEARCH OF THE RELIEF OF HEAT STRESS ON THE REPRODUCTIVE PERFORMANCE OF BREEDING PIGS
-A PRELIMINARY REPORT
C. W. Liao1＊, F. C. Liu1, A. L. Hsu1, H. F. Lee4, T. M. Su5, C. B. Hsu2, and Y. H. Jea3
1Nutrition division, Livestock Research Institute, Council of Agriculture, Hsinhua, Tainan 712, Taiwan, R. O. C.
2Kaohsiung Animal Propagation Station, Livestock Research Institute, Council of Agriculture, Neipu, Pingtung 912,Taiwan, R. O.C.
3Chunghua Animal Propagation Station, Livestock Research Institute, Council of Agriculture, Peido, Changhua, 521, Taiwan, R. O.C.
4Animal Industry Division, Livestock Research Institute, Council of Agriculture, Hsinhua, Tainan 712, Taiwan, R. O. C.
5Animal Management Division, Livestock Research Institute, Council of Agriculture, Hsinhua, Tainan 712, Taiwan, R. O. C.
*Corresponding author, e-mail:
chungwen@mail.tlri.gov.tw
.
ABSTRACT
The objective of this study was to investigate the effect of lactating sows reared in either the water-pad cooling barn or conventional open air barn on reproduction efficiency and growth of piglets. A total of 64 Landrace-gestating sows were used as the experimental animals. Sows were divided into 2 groups and raised in either the conventional open air barn (COAB) or in the water-pad cooling barn (WPCB) from 108th day of pregnancy to 30th day of lactation when piglets were weaned. The experiment was performed during the hot season (from June to September in Taiwan). The reproductive performance of sows and growth performance of piglets were measured. The results showed that there was no difference on bodyweight and the backfat thickness of sows raised in the two barns. Sows in the WPCB tended to have larger backfat thickness loss and lower feed intake than in the COAB. There was a shorter interval from weaning to oestrus for sows raised in WPCB. For the nursing piglets, there were no difference on the litter size at birth, weaning and live piglets at birth. The weight gain during lactation for piglets raised by sows under WPCB was higher (P＜0.05) than those in COAB. The preliminary results showed that there was a beneficial effect on the reproduction efficiency of lactating sows and growth of piglets when sows were raised in WPCB during the hot season in Taiwan.
KEY WORDS: Conventional open air barn, Water-pad cooling barn, Sows, Piglets, Reproductive efficiency.
INTRODUCTION
Taiwan locates in the subtropic or tropic area. The duration of high temperature and humidity can reach eight months per year, which leads to heat stress effect on animals production. The high ambient temperature has a negative effect on growth performance of pigs and reproductive performance of sows (Black et al., 1993; Quiniou and Noblet, 1999; Laspiur and Trottier, 2001; Renaudeau and Noblet, 2001). The thermoneutral zone for sows is 18-21℃. When the temperature is above 30℃, sow will reduce (18.8-45.7%) feed intake and subsequently, the milk output during lactating period (Christon et al., 1999). The application of water pad cooling system can decrease the inner temperature of sow barn by increasing the cooling air ventillation rate. Therefore, this purpose of this experiment was to investigate the effect of applying water pad cooling barn on the reproduction efficiency of sows and growth performance of piglets during the hot season in Taiwan.
MATERIALS AND METHODS
Animals and diet
A total of 64 Landrace sows were used in this experiment. At the 108th day of gestation, sows were divided into two groups. The sows in control group were raised at the conventional open air barn (COAB). The sows in the experiment group were raised at the water-pad cooling barn (WPCB). The diet for lactating sows was formulated by the Feeding Standard for Pigs in Taiwan (1990) and contained 15% crude protein and 3300 kcal/kg digestible energy. During the experimental period, sows were provided feed and water ad libitum. Piglets were weaned at the age of 30 ± 2 day. The backfat thickness of sows was measured with the supersonic backfat detector. Feed intake, bodyweight, backfat thickness and the interval from weaning to estrus of sows were measured. The litter size and bodyweight at birth and weaning, survival rate of piglets were determined also.
Statistical procedure
Data collected were analyzed by ANOVA as a completely randomized design. Experiment units were individual sows. All procedures of statistical analysis were computing using the General Linear Model by Statistical Analysis System (SAS, 1990).
RESULTS AND DISCUSSION
The application of WPCB on the sows during lactating period reduced the body weight loss, interval from weaning to estrus of sows (Table 1). Nevertheless, the backfat thickness loss during lactation tended to be larger possibly due to reduced feed intake for sow in WPCB. Our results was also found in the studies of Prunier et al. (1997) and Christon et al. (1999). Liao and Hsu (1987) and Renaudeau et al. (2003) reported that the larger bodyweight loss of sows during lactating period prolonged the interval from weaning to oestrus.
In the growth of piglets, there was no difference on the litter size and live piglets at birth, litter size at weaning and bodyweight at birth, survival rate of piglet between COAB and the WPCB (Table 2). Piglets raised in the WPCB had heavier (P < 0.05) body weight at weaning and larger (P < 0.05) weight gain during lactation.
Therefore, the preliminary result showed that piglets had larger weight gain during lactation period when the sows were raised in the WPCB. The application of WPCB for the lactating sows during hot season in Taiwan area can benefit the reproductive performance of sows and growth performance of piglets. Further investigation is under conducting to draw the conclusion of applying the WPCB on the alleviating function of heat stress adverse effect on sow under the subtropic area.
Table 1. The effect of sows raised in either conventional open air barn or water-pad cooling
barn on the reproduction efficiency of sows
Items COAB WPCB SEM
Number of sows 11 7
Bodyweight at farrowing, kg 188.7 199.0 5.8
Bodyweight at weaning, kg 162.3a 183.8b 6.8
Bodyweight loss during lactation, kg 26.3 a 15.2 b 4.9
The backfat thickness at birth, mm 12.4a 20.6 b 2.7
The backfat thickness at weaning, mm 10.5a 17.8 b 2.3
Backfat loss during lactation, mm 1.9 2.8 0.8
Feed intake, kg/d 3.61 3.20 0.3
Interval from weaning to estrus, d 15.3 7.2 4.8
a,b Means within the same row without common superscripts differ significantly (P < 0.05) .
Table 2. The effect of sows raised in either conventional open air barn or water-pad cooling
barn on the growth performance and survival rate of nursing piglets
Items COAB WPCB SEM
Number of sows 11 7
Litter size at birth 10.7 9.8 0.7
Live piglet at birth 9.0 8.6 0.8
Litter size at weaning 8.4 8.4 0.7
Bodyweight of piglet at birth, kg 1.5 1.5 0.01
Bodyweight of piglet at weaning, kg 6.2a 8.5b 0.4
Weight gain during lactation, kg 4.7a 7.1b 0.4
Survival rate of piglet, % 93.7 97.1 3.2
a,b Means within the same row without common superscripts differ significantly (P < 0.05) .
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