Effect of advanced reproductive technologies on smallholders' pig productivity in Gauteng Province

Abstract

Pigs are of high economic importance, especially among the smallholder pig farmers as they contribute to human nutrition, food security, poverty alleviation, enhanced livelihood and creation of employment for the rural community. However, reproductive inefficiency is the main limiting factor due to inaccessibility to superior germplasm. Therefore, advances in reproductive technologies such as oestrus synchronization and artificial insemination (AI) offers unprecedented opportunities for livestock improvement for smallholder pig farmers. The first objective determined the status of pig productivity in smallholder farms of Gauteng Province prior to the introduction of advanced reproductive technologies (ARTs). The population was divided into four strata, namely West Rand, Ekurhuleni, Tshwane and Sedibeng district municipalities. A proportional stratified random sampling procedure was used to select 71 smallholder pig farmers with the assistance of extension officers from Gauteng Department of Agriculture and Rural Development (GDARD). The majority of the respondents were males (67%) and were above 50 years of age (67%), whilst 56% of the respondents had high school education. Majority of the respondents privately owned the farms (62%) and the farm infrastructure had facilities with low cost housing and modern facilities. Additionally, 47% of the respondents fed their pigs with feed swill. A large proportion of the respondents did not vaccinate their pigs (81%). Majority of respondents did not identify their pig herds (63%). Interestingly, majority of the respondents did not have breeding boars (73%) and sold their pigs at auctions (70%). The second objective determined semen characteristics evaluated by a Computer Aided Sperm Analyser® (CASA®) as a measure of boar fertility to be used for artificial insemination (AI). Sixteen ejaculates were collected from three Large White boars that are routinely used for semen collection purposes using the gloved-hand technique. The semen was extended with a commercial semen extender; Beltsville Thawing Solution, and the AI dose used consisted of 80mL semen sample (3×109 spermatozoa/mL). Aliquots of diluted semen were evaluated for spermatozoa motility using CASA®. Spermatozoa viability was evaluated using Synthetic Binding CD-14 (SYBR+)/Propidium Iodide (PI-), whereas spermatozoa morphology was evaluated using Eosin Nigrosin stain. The average semen volume, concentration and pH were 210 mL, 264.8 x 106 spermatozoa/mL and 7.1, respectively. The average values for total spermatozoa motility was 95.1%, ranging from 82.7 and 98.5%. However, XIX

there were lower values found for progressive spermatozoa motility, ranging from 13.6 to 39.0%. The mean values for morphologically normal spermatozoa ranged from 47.8-60.9% and live spermatozoa ranged from 71.8-77.7%. The third objective determined sow fertility following AI at smallholder farms A total of 73 multiparous sows were artificially inseminated. Conception rates, farrowing rates, litter size and number born alive were recorded. The average conception and farrowing rates were 78.1 and 57.5%, respectively. Furthermore, AI resulted in acceptable fecundity (i.e., 11.8 litter size and 10.0 number of piglets born alive). The fourth objective determined the relationship between spermatozoa quality characteristics and sow fertility at smallholder farms in Gauteng Province. Of all fertility characteristics studied, conception rate was significantly related to total spermatozoa motility rate (r= 0.37, P<0.01), progressive motility (r= 0.31, P<0.01) and rapid motility (r= 0.40, P<0.01), although relatively low. There was a low negative relationship between spermatozoa morphological characteristics and fertility (P>0.05). The fifth objective determined the pre-weaning growth performance of piglets born following AI at smallholder farms of Gauteng province. Individual piglets were weighed using an electronic weighing scale. Litter size, number of piglets born alive, number of piglets weaned, the average piglet birth weight and average piglet weaned weight were recorded. The average litter size was 11.8 ± 0.2. The average birth weight and weaning weights were 1.9 and 6.2 kg, respectively. No significant differences were found between male and female piglets for all the growth performance characteristics. Piglets born during winter had a significantly higher (P<0.05) birth and weaning weight as compared to autumn and summer months. Season had a significant effect on birth and weaning weight (P<0.01). However, sex of piglets had no effect on all the characteristics recorded (P>0.05). The interaction between sex and season was only observed on the total number of weaned piglets (P<0.01). A highly significant positive correlation was found between litter size and number of piglets born alive (r= 0.86) and total number of piglets weaned (r= 0.50). A highly significant correlation was found between total number of piglets born alive and total number of piglets weaned (r= 0.55). In conclusion, the study demonstrated the potential benefit of adopting AI technology under smallholder production systems to disseminate superior genetic material to smallholder pig farmers in Gauteng Province. The total spermatozoa motility, progressive and rapid spermatozoa motility were the only spermatozoa motility characteristics significantly correlated XX

with conception rate. Conversely, litter size and number born alive were not correlated with CASA® spermatozoa motility attributes. No relationships existed between spermatozoa morphological characteristics and fertility. The sex ratio percentage of piglets born following AI was 52:48% (females: males). The number of piglets born alive was 10.2 and 9.5 for number piglets weaned. Season influenced birth to weaning weight. However, sex had no significant influence at birth and weaning weight. Litter size affects the number of piglets born alive and weaned. The study showed that the introduction of advanced reproductive technologies improved productivity of pigs at smallholder pig farms in Gauteng Province.