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Workshop-Seminar on Making Better Use of Local Feed Resources. SAREC-UAF, January 2000

 

The effect of dietary protein level on the reproductive
performance of Mong Cai sows

 

Hoang Nghia Duyet and Nguyen Thi Loc

 

Hue University of Agriculture and Forestry

 

Abstract

 

The effects on the reproductive performance of Mong Cai sows of three crude protein (CP) concentrations in gilt (Stage1), gestation (Stage 2) and lactation (Stage 3) diets were evaluated. Dietary treatments LP, MP and HP consisted of 10, 12 and 14% CP in gilt diets, 8, 10 and 12% CP in gestation and 12, 14 and 16% CP in lactation, respectively. In the gilt rearing period the low (10%) CP diet resulted in significantly higher mean age and lower live weight at first oestrus compared to the medium and high CP diets, which were not significantly different from each other. In gestation the low (8%) CP diet gave significantly lower piglet and total litter live weights at birth than the medium and high CP treatments, although mean litter size was not affected by diet.  The low (12%) CP lactation diet resulted in significantly lower mean piglet and total litter weaning weights, higher sow live weight losses to weaning and longer weaning to oestrus intervals. The differences for all parameters measured between the medium and high CP diets were small and non-significant. It is concluded that the optimum levels of CP are 12% in gilt rearing diets, 10% in gestation, and 14% in lactation diets.

 

Key words: Mong Cai sows, reproduction, dietary protein

 

Introduction

Protein plays an important role in sow nutrition and a considerable amount of work has been done on the effect of protein level on the reproductive performance of sows  (Wahlstrom and Libal 1977; Cunningham et al 1974). Jones and Maxwell (1974) showed that 10% of crude protein (CP) in the diet gave low body weight gains of gilts. Atinmo et al (1974) fed pregnant sows diets with a CP level of 5%, and observed lower brain weights of the piglets and lower body weights at birth. Mahan et al (1977) showed that 8-9 % of CP in the gestation diet caused low litter size at birth and low growth rates of piglets.

 

Vietnam has about 1 million Mong Cai sows, which is around 50% of the total sow population, and the breed is particularly popular in the North and Central parts of the country, where it is used as parent stock for the production of crossbred fatteners. However, little research has been done on the protein requirements of Mong Cai sows. On the country’s state farms, diets are still based on the recommendations of the Animal Husbandry Institute from 1980. In the rural areas farmers often feed Mong Cai sows with low levels of protein based on locally produced feed resources, such as crop residues and agro-industrial by-products.

 

 

Objectives of the research

 

·        To determine the effect of protein level on the growth rate and age at puberty of growing MongCai gilts.

·        To determine the optimum dietary protein level for MongCai sows in pregnancy and lactation.

 

Materials and methods

 

The experiment was divided into three periods:

 

Stage 1: Effect of protein level on the growth rate and age at puberty of Mong Cai gilts.

Animals and management:

Eighteen Mong Cai gilts were purchased from a breeding area after weaning at 8-10 kg live weight. After 1 week for adaptation and vaccination, they were randomly allocated to 3 treatments (each treatment consisting of 3 gilts, with two replicates per treatment) and given the following diets:

 

Dietary treatments:

·        Low (10% CP) protein (LP);

·        Medium (12% CP) protein (MP);

·        High (14% CP) protein (HP).

 

Measurements:

Growth rate, feed intake, feed conversion ratio (FCR), age and live weight at first oestrus, age and live weight at first mating and FCR during pregnancy were measured.

 

Stage 2: Effect of protein level in the diet of pregnant Mong Cai sows on reproductive performance

Dietary treatments:

·        Low (8 % CP) protein (LP)

·        Medium (10% CP) protein (MP)

·        High (12% CP) protein (HP)

 

Measurements:

Liveweight gain during pregnancy, and litter size, live weight and mortality of the piglets at birth were measured.

 

Stage 3: Effect of protein level in the diet during lactation on the reproductive performance of Mong Cai sows.

 

Dietary treatments: 

·        Low (12% CP) protein (LP)

·        Medium (14% CP) protein (MP)

·        High (16% CP) protein (HP).

 

Measurements:

Litter size at weaning, liveweight of the piglets at weaning, total liveweight of the piglets at 21 days of age, liveweight loss of the sow during lactation, time interval (days) from weaning to oestrus of sow, number of litters per year and FCR were measured.

 

 

 

 

 

 

 

 

Results and discussion

The effects of dietary crude protein level on the live weight changes in the gilts are shown in Table 3.

 

 

 

 

 

Mong Cai gilts had significantly lower growth rates when fed the low protein diet. Live weight at 8 months of age was 42 kg in treatment LP, 48 kg in treatment MP and 54 kg in treatment HP, which implies mean daily gains of 183 g/day, 217 g/day and 250 g/day, respectively (P <0.01). There were no significant differences found between treatments MP and HP. Feed conversion was best in treatment HP and worst in treatment LP (Table 4), as a result of the lower daily live weight gains of the low protein group.

 

 

 

Mean ages at first oestrus and first mating (Table 5) were lower in treatment HP than in treatments MP (P<0.05) and LP (P<0.01).  Mean live weights at first oestrus and mating were also higher in treatment HP than in treatments LP (P<0.01), and in treatment MP compared to LP (P<0.05). The difference between treatments MP and HP was not significant.

 

Mean piglet birth weights and total litter weight at birth, 21 days and weaning (Tables 6 and 7), were lower for the LP sows than for the MP and HP groups (P<0.05).  There was a tendency for smaller litter sizes at birth and weaning in the LP group, but the differences were not significant.

 

Mean body weights at mating and after farrowing were lower for the LP group compared with the MP and HP treatments (P<0.05), although net live weight gains in gestation were similar for all treatment groups (P>0.05). Similarly the LP sows lost significantly more live weight during lactation than the MP and HP sows, and this is probably the explanation for their longer weaning to oestrus interval (15.8 days, compared to 4.6 days for the MP sows and 4.0 days for the HP sows).  Although the total feed intake for the whole reproduction cycle was lower for the LP sows, total feed per kg of weaned piglet produced was significantly higher than for the MP and HP groups.

 

 

Table 6. Effect of dietary protein level in gestation and lactation on reproductive performance of Mong Cai sows
	LP	MP	HP	LP-MP LP-HP  MP-HP
Piglets born	9.0 ±1.87	11.2± 2.17	10.6 ± 1.82	NS	NS	NS
Piglet born alive	9.0 ± 1.87	10.0± 1.22	10.4 ± 1.52	NS	NS	NS
Birth weight (g)	617± 30.0	695 ± 38.0	728±54.0	*	*	NS
Litter birth weight (kg)	5.5 ± 1.29	7.7 ± 1.21	7.8 ± 1.27	*	*	NS
Gestation (days)	113 ± 0.6	113± 0.5	113± 0.8	NS	NS	NS
Farrowing time (hours)	4.5 ± 4.0	4.3± 2.2	3.5 ±1.3	NS	NS	NS
Litter weight (kg) at 21 days	22.1 ± 1.5	27.1 ± 3.0	28.1± 3.8	*	*	NS
Litter size at weaning	7.8 ± 1.1	9.0 ± 1.0	9.2± 0.4	NS	NS	NS
Piglet weaning weight, kg	6.4 ± 0.4	8.5± 0.9	8.2± 0.7	**	**	NS
Total weaning weight, kg	49.6 ± 3.2	76.9± 9.0	75.6± 7.9	**	**	NS
Mortality, birth to weaning, %	13.3	10.0	11.5

 

 

Table 7. Effect of dietary protein level on reproductive parameters of Mong Cai sows
	LP             MP               HP			LP-MP LP-HP MP-HP
Sow body weight at mating, kg	42 ± 2.3	47 ± 1.7	50 ± 2.2	*	*	NS
Sow body weight after farrowing, kg	74 ± 4.6	79 ± 3.2	83± 4.2	NS	*	NS
Net weight gain in pregnancy, kg	32	32	33	NS	NS	NS
Feed intake during pregnancy, kg	169 ± 4.0	174 ± 4.1	174± 0.3	NS	*	NS
FCR, kg feed/kg WG	4.0	4.1	4.1	NS	NS	NS
Sow body weight  at weaning, kg	51 ± 1.8	65 ± 3.1	70± 6.2	**	**	NS
Sow weight loss in lactation, %	31	18	16	*	*	NS
Post weaning oestrus, days	15.8± 2.6	4.6 ± 1.1	4.0 ± 0.7	**	**	NS
Reproductive cycle, days	177± 2.6	166 ± 1.3	165 ± 0.8	**	**	NS
Sow feed intake in lactation, kg	100	155	147
Piglet feed intake to weaning, kg	34	65	61
Total feed/cycle, kg	302±19.1	394±23.2	381±20.5	**	**	NS
Feed/kg piglet produced, kg	6.1± 0.3	5.1± 0.3	5.0± 0.2	**	**	NS

 

 

Conclusions and recommendations

·        In the rearing period, diets with medium (12% CP) and high (14%CP) crude protein contents significantly increased gilt growth rates and live weight at first oestrus and mating, and reduced age at puberty.

·        Medium (10% CP) and high protein (12% CP) diets in gestation increased piglet birth weights.

·        Medium (14% CP) and high (16% CP) protein diets in lactation increased piglet live      weights at 3 weeks and weaning, and reduced mortality to weaning.

·        The low (12% CP) protein lactation diet resulted in increased sow live weight losses in lactation and increased weaning to service intervals.

 

The differences between the medium and high crude protein diets for the reproductive parameters measured were not significant. Therefore, the diets containing the medium levels of protein in the rearing (12% CP), gestation (10% CP) and lactation (14% CP) periods are recommended, as they are less expensive than the high protein diets.

References

 

Atinmo T,   Pond W G and Barnes  R H  1974 J Anim Sci  39:703

 

Cunningham P J et al  1974.  J Anim Sci 39:63

 

Jones R D and Maxwell C D  1974. J Anim Sci  39: 1067

 

Mahan D C,  Moxon A L and Hubbard M  1977. J Anim Sci  45:738

 

Wahlstrom R C  and  Libal G W  1977. J Anim Sci 45:94