A comparison of the susceptibility of growing mukota and large white pigs to infection with Ascaris suum

Status and gaps of research on respiratory disease pathogens of swine in Africa

Over the last two decades, the pig population in Africa has grown rapidly, reflecting the increased adoption of pig production as an important economic activity. Of all species, pigs are likely to constitute a greater share of the growth in the livestock subsector. However, constraints such as respiratory infectious diseases cause significant economic losses to the pig industry worldwide. Compared to industrialized countries, the occurrence and impacts of respiratory diseases on pig production in Africa is under-documented. Hence, knowledge on prevalence and incidence of economically important swine respiratory pathogens in pigs in Africa is necessary to guide interventions for prevention and control. The purpose of this review was to document the current status of research on five important respiratory pathogens of swine in Africa to inform future research and interventions. The pathogens included were porcine reproductive and respiratory syndrome virus (PPRSv), porcine circovirus 2 (PCV2), Mycoplasma hyopneumoniae (M. hyopneumoniae), Actinobacillus pleuropneumoniae (APP) and swine influenza A viruses (IAV). For this review, published articles were obtained using Harzing's Publish or Perish software tool from GoogleScholar. Articles were also sourced from PubMed, ScienceDirect, FAO and OIE websites. The terms used for the search were Africa, swine or porcine, respiratory pathogens, M. hyopneumoniae, APP, PCV2, PPRSv, IAV, prevention and control. In all, 146 articles found were considered relevant, and upon further screening, only 85 articles were retained for the review. The search was limited to studies published from 2000 to 2019. Of all the studies that documented occurrence of the five respiratory pathogens, most were on IAV (48.4%, n = 15), followed by PCV2 (25.8%, n = 8), PPRSv (19.4%, n = 6), while only one study (3.2%, n = 1) reported APP and M. hyopneumoniae. This review highlights knowledge and information gaps on epidemiologic aspects as well as economic impacts of the various pathogens reported in swine in Africa, which calls for further studies.

Herd dynamics reflect constraints for pig production and farmer attitudes in smallholder systems in Lao PDR

A field intervention and 17 months’ monitoring of pig herd dynamics in seven villages in Northern Laos was conducted. The collected data show for the first time herd dynamics based on quantitative data. They show that dynamics follow a regular cyclic pattern based on the general farm management approach applied by farmers, which lacks a specific pig management focus. Interventions aimed at improving animal management and nutrition were far less successful than envisioned but revealed major conflicts in perception between implementers and farmers. Farmers did not shift their focus to pig production as major income-generating activity as envisioned by implementers. Nevertheless, despite only partially improved systems, farrowing and animal growth rates were increased among committed farmers, whereas death rates have decreased. However, our quantitative data show a significant number of constraints reflected in the way how animals enter, pass through and leave smallholder production systems. Disease and disease prevention, as well as animal feeding are the two dominant hindrances to improved production. Both these obstacles are rather related to a lack of focus on animal production and therefore animal requirements than to an inherent lack of understanding. To increase interest though, poor income opportunities due to lacking market opportunities will have to be tackled. However, even with an incomplete transition from a traditional to an improved system, overall production increased by 600% in committed farmers with an about equivalent increase in income from this activity, showing that current systems leave massive scope for improvement if perceptions and other external obstacles such as access to inputs and markets can be overcome.

Chromosomal profile of indigenous pig (Sus scrofa)

AIM

The objective of this study was to investigate the chromosomal profile of indigenous pigs by computing morphometric measurements.

MATERIALS AND METHODS

A cytogenetic study was carried out in 60 indigenous pigs to analyze the chromosomal profile by employing the short term peripheral blood lymphocyte culture technique.

RESULTS

The modal chromosome number (2n) in indigenous pigs was found to be 38 and a fundamental number of 64 as in the exotic. First chromosome was the longest pair, and thirteenth pair was the second largest while Y-chromosome was the smallest in the karyotype of the pig. The mean relative length, arm ratio, centromeric indices and morphological indices of chromosomes varied from 1.99±0.01 to 11.23±0.09, 1.04±0.05 to 2.95±0.02, 0.51±0.14 to 0.75±0.09 and 2.08±0.07 to 8.08±0.15%, respectively in indigenous pigs. Sex had no significant effect (p>0.05) on all the morphometric measurements studied.

CONCLUSION

The present study revealed that among autosomes first five pairs were sub metacentric, next two pairs were sub telocentric (6-7), subsequent five pairs were metacentric (8-12) and remaining six pairs were telocentric (13-18), while both allosomes were metacentric. The chromosomal number, morphology and various morphometric measurements of the chromosomes of the indigenous pigs were almost similar to those established breeds reported in the literature.

Estimation of genetic parameters for growth performance and carcass traits in Mukota pigs

The objective of the study was to determine genetic parameters for growth and carcass traits in Mukota pigs, maintained on a fibrous diet. Records (n = 1961) were obtained from a population housed at the University of Zimbabwe Farm (Harare, Zimbabwe) between January 1998 and August 2003. Backfat thickness was measured at 50 and 75 mm (K5 and K7.5), respectively. Carcass length (CL) was measured from the anterior edge of the first rib to the pubic bone using a measuring tape. Variance components were estimated using a model that accounted for direct, common environmental litter and maternal genetic effects, using average information restricted maximum likelihood. Heritability estimates for average daily gain from birth to weaning (ADGW) and average daily gain from weaning to 12 weeks (ADG1) were 0.15 and 0.27, respectively. Maternal genetic effects accounted for 2.6% of variation for ADG1. Heritability for average daily gain from 12 weeks to slaughter (ADG2) was 0.20. Common environmental litter effects accounted for 18% of phenotypic variance for cold dressed mass (CDM). Heritability estimates for CDM and CL were 0.32 and 0.62, respectively. Maternal genetic effects accounted for 10.5% of variance in CL. Heritability estimates for K5 and K7.5 were 0.64 and 0.40, respectively. The CDM was positively genetically correlated to K5, but negative to K7.5. The K5 and K7.5 had a high genetic correlation (0.88). Genetic correlations between ADGW and K5, K7.5 and CL were 0.30, 0.05 and 0.35, respectively. The existence of sufficient genetic variation makes genetic improvement for many growth and carcass traits in the Mukota breed possible through effective selection methods.

Herd dynamics and contribution of indigenous pigs to the livelihoods of rural farmers in a semi-arid area of Zimbabwe

Herd dynamics of indigenous pigs were determined in a semi-arid farming area of Chirumanzu, Zimbabwe. Thirty-two pig herds were monitored once every month for 12 months. Consequently, pig production potential (PPP) and pig production efficiency (PPE) were computed for each month. Incidences of farrowing were higher in times of pig confinement (57%) than in times when the pigs were free ranging (43%). About 23% of the farmers interviewed had access to irrigation. The mean pig herd size per household was 3.3. The average litter size per farrowing was 7.7. Pigs were free ranging for most of the year and penned during the rainy season. Herd sizes changed with month (P<0.05). Farmers who had access to irrigation had higher (P<0.05) herd sizes, number of piglets and the number of adult pigs. Highest piglet numbers were observed during the rainy months. The number of mature pigs contributing to pig production efficiency was low. Piglet mortality was the major cause of exits from the herd and was higher in farmers with no access to irrigation facility (P<0.05). The PPP was highest in farmers who had access to irrigation (P<0.05), except in June and July. The PPE was low and not affected by either month, village or access to irrigation (P>0.05). It can be concluded that pig production efficiencies were low and intervention strategies to improve them need to be developed.