Reproduction and piglet performance in Mong Cai gilts fed a mixture of taro leaf silage and water spinach

Bounlerth Sivilai, Malavanh Chittavong and T R Preston*

Faculty of Agriculture, National University of Laos (NUoL), Vientiane city, Lao PDR
lerth_si@yahoo.com
* TOSOLY, AA48 Socorro, Colombia

Abstract

Nine Mong Cai gilts, with average initial body weight of 35 kg, were allocated to 3 households in Phuert village, Namor district, Oudomxay province. In each household, the 3 pigs were allocated to 3 treatments according to a Completely Randomized design. The households were the replicates. The treatments were: T20: Mixture of rice bran and maize meal supplemented with mixture of water spinach  and Taro leaf silage (50:50 DM basis) at  20 % of the diet DM; T40 and T60 similar to T20 but with 40 and 60% of Taro leaf silage. The gilts were mated at third oestrus by natural mating with the same local Lao boar. The feeding level was 4% of live weight (DM basis) until pregnancy was confirmed, after which it was restricted to 1.5% of live weight.  In the lactation period the gilts were fed increasing amounts up to five days after farrowing and from then onwards feeds were offered ad libitum.

The two vegetative sources had less than half the crude fiber present in the rice bran and twice the concentration of crude protein; live weight at farrowing and rate of live weight gain during pregnancy declined as the proportion of the mixture of taro leaf silage and water spinach increased. All sows retuned to estrus within 7 days after weaning, with no differences among treatments. There were no differences among treatments in the numbers of piglets born and weaned and in mortality. The highest litter live weight at weaning was with the diet T40 with no differences between the diets with the least and highest levels of forage.

It is concluded that a mixture of taro leaf silage and water spinach can be used in the diet of Mong Cai gilts in pregnancy and lactation without affecting reproduction criteria, measured as numbers of live piglets born and weaned, and the interval from weaning to estrus.

Key words: Estrus, feed intake, growth rate, litter size, litter weight, mortality, on-farm trial

Introduction

In Laos, where most farmers grow paddy rice for home consumption and/or sale, pig diets are usually based on rice bran as the main ingredient, fed together with a small amount of green feed. Green feed or vegetable matter is traditionally collected from forest margins and fallow fields and includes Colocasia esculenta, Alocasia macrorrhiza, Crassocephalum crepidioides, paper mulberry leaves and several other herbs, depending on local availability (Phengsavanh and Stur 2006).

Recent research from Laos showed that a mixture of taro (Colocasia esculenta) leaf silage and water spinach can replace up to 100% of soybean meal in pregnancy and lactation diets for Mong Cai gilts with no effect on sow reproduction and only a slight decline in litter size and weight at weaning (Chittavong et al 2007).

The hypothesis underlying the present study is that Mong Cai gilts will have acceptable reproductive performance managed under farmer conditions in the mountainous northern region of Laos but with improved protein nutrition by incorporating in the diet Taro leaf silage and Water spinach.

Materials and methods

Location and climate

The experiment was carried out in Phuert village, Namor district, Oudomxay province, Lao PDR.

Experimental animals and design

Nine Mong Cai gilts, with average initial body weight of 35 kg, were allocated to 3 households with 3 pigs in each. In each household, the 3 pigs were allocated to 3 treatments according to a Completely Randomized design. The households were the replicates. The three treatments were:

T20: Mixture of rice bran and maize meal supplemented with water spinach  and taro leaf silage at 20 % of the diet DM

T40: Mixture of rice bran and maize meal supplemented with water spinach  and taro leaf silage at 40% of the diet DM

T60: Mixture of rice bran and maize meal supplemented with water spinach  and taro leaf silage at 60% of diet DM

Housing

The gilts were housed in individual pens made from bamboo, in an open-sided building with a thatch roof of Imperata grass.  The size of each pen was 1.0*1.5m.

Feeding

The energy component of the diet was rice ban and maize meal in different combinations according to the wishes of each household (Tables 1 and 2 ).

The taro leaves were collected around the village. Some of the water spinach was grown on farms of participating farmers; but most were purchased in the area around the village. Water spinach and ensiled taro leaves were chopped into small pieces and mixed with the other ingredients of the diet (maize meal and rice bran) prior to feeding. The mixed feeds were given to the pigs in 2 meals daily (7:30 and 16:30h). Water was permanently supplied through drinking nipples.

Management and feeding

The gilts were de-wormed and were adapted to the dietary treatments for 14 day period before starting the experiment. The Mong Cai gilts were mated at third oestrus by natural mating with the same local Lao pig. The feeding level was at 4% of live weight (DM basis) until pregnancy was confirmed, after which it restricted to 1.5% of live weight.  In the lactation period the gilts were fed increasing amounts up to five days after farrowing and from then onwards feeds were offered ad libitum.

Measurements

The gilts were weighed every 14 days during gestation, after farrowing and then every 2 weeks until the end of lactation (42 days). The piglets were weighed at birth and then every 2 weeks to weaning. Records were kept of: feed intakes during the gestation and lactation periods; litter size at birth and at weaning; weight of piglets at birth and weaning; mortality of the piglets at birth; live weight of the sows during lactation; and the interval from weaning to estrus..

Samples of water spinach, maize meal and rice bran were taken for analysis when they were purchased. Samples of taro leaves were taken at the time of ensiling.

Chemical analyses

Feed samples were analyzed for DM by micro-wave radiation (Undersander et al 1993). Nitrogen, ash and crude fiber were determined according to AOAC (1990).

Statistical analysis

The data were analyzed using the General Linear Model procedure of the ANOVA software in the MINITAB 13.31 program (2000). Sources of variation were treatments and error.

Results

Ingredient and chemical composition of the diets

The analysis of the diets (Table 3) showed that the two vegetative sources had less than half the crude fiber present in the rice bran and twice the concentration of crude protein.

There were no significant differences among treatments in live weight at service (Table 4). However, live weight at farrowing and rate of live weight gain during pregnancy declined as the proportion of the mixture of taro leaf silage and water spinach increased.

Live weight change of sows in lactation

Live weight of the sows at weaning deceased as the proportion of Water spinach and taro leaf silage increased; however, the relative loss of weight was lowest for the diet with the highest level of forage (Table 5; Figure 1).

Reproductive traits

All sows retuned to estrus within around 7 days after weaning, and mean weaning to oestrus interval did not differ among treatments.

Piglet performance in lactation

There were no differences among treatments in the numbers of piglets born and weaned and in mortality (Table 6). The highest litter live weight at weaning was with the diet T40 with no differences between the diets with the least and highest levels of forage.

Discussion

The lower live weights at farrowing and at the end of lactation for the Mong Cai gilts fed the highest levels of forages (75% of the diet DM in pregnancy and 70% in lactation) were not reflected in reproductive performance which was broadly similar on all diets. Weight losses of sows during the 42 days lactation were 0.33, 0.37 and 0.20 kg/day for TW0, TW40, and TW60, respectively, which is similar to the findings of Chittavong et al (2007), who reported a mean weight loss of Mong Cai sows during 42 and 49 days lactation of 0.21 kg/day.

It is interesting to note that although the gilts fed the high forage diet (T60) weighed 25% less at farrowing than those on the low forage diet (T20), they lost less weight during lactation and had similar litter numbers and weights at weaning. Most important was the fact that they returned to estrus at the same time as the gilts on the low forage diet.

These findings recorded under practical small farm conditions show the capacity of the Mong Cai gilts to partition nutrients to maintain vital processes such as reproduction.

Conclusions

• A mixture of taro leaf silage and water spinach can be used as the main protein source  in the diet of  Mong Cai gilts in pregnancy and lactation without affecting reproduction, measured as numbers of live piglets born and weaned, and the interval from weaning to estrus.

Acknowledgments

The authors would like to acknowledgment the financial support from MEKARN project financed by Sida, Sweden. Thanks also to the Faculty of Agriculture, National University of Laos and Agriculture and Forestry division of Odomxay province, office of Namor district for cooperation and facilities. The authors would also like to thank the head of Phuert village, for field assistance with care of the animals during the experiment.

References

AOAC 1990 Official Methods of Analysis. Association of Official Analytical Chemists. 15^th Edition (K Helrick editor). Arlington pp 1230.

Chittavong Malavanh, Preston T R and Ogle B 2007 Effect of replacing soybean meal by a mixture of taro leaf silage and water spinach on reproduction and piglet performance in Mong Cai gilts.  MSc Thesis, MEKARN-SLU   http://www.lrrd.org/lrrd20/supplement/mala2.htm

Phengsavanh P and Stur W 2006 The use and potential of supplementing village pigs with Stylosanthes guianensis in Lao PDR Workshop-seminar “Forages for Pigs and Rabbits” MEKARN-CelAgrid, Phnom Penh, Cambodia, 22-24 August,  2006.  http://www.mekarn.org/proprf/wern.htm

Undersander D, Mertens D R and Theix N 1993 Forage analysis procedures. National Forage Testing Association. Omaha pp 154.

Received 6 November 2009; Accepted 13 March 2010; Published 1 April 2010

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