Relationship between sperm plasma membrane integrity and morphology and fertility following artificial insemination

Sperm quality plays an important role in determining fertility. The aim of the study was to examine the relationship between sperm plasma membrane integrity and morphology, and fertility following artificial insemination (AI). A total of 16 ejaculates were collected from three Large White boars using the gloved hand technique. The semen was extended with a commercial extender. The AI dose contained 80 mL semen sample (3 × 109 sperm/mL). Aliquots of diluted semen were assessed for sperm plasma membrane integrity (synthetic binding CD-14 (SYBR+)/propidium iodide (PI-) and sperm morphology (eosin nigrosin). A total of 73 Duroc-type, Large White and nondescript multiparous sows from smallholder farms were inseminated with extended semen samples. Boar sperm plasma membrane integrity and morphology were subjected to one-way analysis of variance (ANOVA). The average boar sperm plasma membrane integrity and normal sperm morphology were 78.6% and 77.2%, respectively. The average conception and farrowing rates following artificial insemination (AI) were 78.1 and 57.5%, respectively. A negative correlation was observed between sperm plasma membrane integrity and fertility. There was a weak positive correlation between normal sperm morphology and conception rate (r = 0.11). Additionally, a relationship was observed between normal sperm morphology and litter size (r = 0.37) and total number born alive (r = 0.03), although relatively low. In conclusion, a negative relationship was found between sperm plasma membrane integrity and fertility. Moreover, there was a relationship between morphologically normal sperm and litter size, as well as number of piglets born alive, although relatively low.Keywords: Boar, Eosin Nigrosin, Semen quality, SYBR14/P

Assessment of genetic variation in Bapedi sheep using microsatellite markers

This study was conducted to assess genetic variation in Bapedi sheep using 14 microsatellite markers. Blood samples were collected from 174 unrelated Bapedi sheep on six farms in various districts of Limpopo and from the Agricultural Research Council Animal Production Institute (ARC-API) in Gauteng. Genotypes from other South African indigenous sheep, namely Zulu (N = 14), Damara (N = 11), Dorper (N = 8), and Namaqua (N = 11), were included to represent reference populations. The effective number of alleles averaged 5.6 for across the Bapedi flocks and was 4.9 for the reference breeds. Among the Bapedi flocks, the observed heterozygosity (Ho) ranged from 0.56 ± 0.05 to 0.69 ± 0.03 and expected heterozygosity (He) values were between 0.75 ± 0.04 and 0.88 ± 0.01. Thus, there is considerable genetic diversity within the Bapedi sheep populations. However, the fixation index was high, indicating the possibility of inbreeding becoming a problem for these flocks. A neighbour-joining tree was constructed from the estimates of Nei’s genetic distances among flocks. The presence of Bapedi sheep flocks on all of the main branches of the tree along with one of the reference breeds suggests the present-day Bapedi is not an entirely distinct breed and that there are genetic differences between flocks of these South African indigenous sheep. Sustainable breeding and conservation programmes are needed to control inbreeding and to foreclose possible genetic dilution of Bapedi sheep. Keywords: genetic diversity, germplasm conservation, inbreeding, indigenous shee

Effects of silage sealing films on fermentation dynamics of ensiled maize and nutrient utilization by Damara rams

An experiment was conducted to evaluate the effects of two silage sealing films on whole crop maize (WCM) fermentation, aerobic stability and nutrient digestion by rams. Prior to ensiling (day 0), triplicate samples of the WCM were collected to determine dry matter, pH, water-soluble carbohydrates (WSC), lactic acid (LA) bacterial counts and nutrient concentration. A single bunker silo was divided into eight sections that were ensiled using either a standard polyethylene film (PE) or an orange oxygen barrier (OB) Silostop film for 180 days. After 180 days of ensiling, six silage samples were collected from each replicate. Three samples were used for nutrient analysis and the other three to determine aerobic stability. Sixteen four-year-old Damara rams with an average live weight of ± 54 kg were housed individually in wooden pens (2.2 m2) to determine digestibility of nutrient in the silage. The digestibility study was conducted as a switchover design with four feeding phases. The silage was supplemented daily with 1% urea and fed to the rams ad libitum. Nutritional value of the silage was not (P >0.05) affected by the ensiling films. The OB-ensiled maize had higher (P 0.05) by treatments. The OB film improved the fermentation and aerobic stability of WCM silage but did not influence its nutrient utilization by rams.The National Research Foundationhttp://www.sasas.co.zaam2021Animal and Wildlife Science

Characterization of seminal plasma constituents of unimproved indigenous and Tankwa goats

The aim of the study was to characterize and compare seminal plasma constituents of unimproved indigenous and Tankwa goats. In this study, unimproved indigenous (11) and Tankwa (11) goats were used. Their average age was 3 ± 0.8 years and average bodyweights were 35.5 ± 2.1 kg and 59.8 ± 1.9 kg, respectively. Semen samples were collected with an electro ejaculator, and evaluated for macroscopic and microscopic semen characteristics and seminal plasma constituents. Both unimproved indigenous and Tankwa goats had normal semen characteristics for goats, with the exception of sperm cell concentration. However, Tankwa goats had higher straight-line velocity and average path velocity compared with unimproved indigenous goats. Unimproved indigenous goats had higher intact acrosome than Tankwa goats. Lipocalin-type prostaglandin-D synthase was one of the constituents that were detected, but it was below the detection limit of 0.5 mmol/L. Moreover, the semen of unimproved indigenous and Tankwa goats had the same levels of fertility-associated antigen, lactate dehydrogenase, sodium, potassium, magnesium, calcium, glucose, cholesterol, triglyceride, lipids and urea. In conclusion, unimproved indigenous and Tankwa goats had the same seminal plasma constituents. These constituents seem to be optimal for the sperm cells, as they resulted in acceptable semen characteristics, except for sperm cell concentration, which was low. Moreover, acceptable standards need to be set for all seminal plasma constituents, as they are not currently known.Keywords: Fertility-associated minerals, genetic variation, semen characteristic

Genetic parameter estimates for tick resistance in Bonsmara cattle

The objectives of the study were to estimate genetic parameters for tick resistance and to evaluate the effect of the level of tick infestation on the estimates of genetic parameters for South African Bonsmara cattle. Field data of repeated tick count records (n = 11 280) on 1 176 animals were collected between 1993 and 2005 by 10 breeders participating in the National Beef Recording and Improvement Scheme. The distribution of tick count records were normalized using a Box-Cox transformation. Data were divided into seven sub-data sets based on the mean tick count per contemporary group, to facilitate the investigation of the effect of level of tick infestation on the derived genetic parameters. A repeatability animal model including the fixed effects of contemporary group and age of animal at tick counting and random effects of the direct additive genetic, permanent environmental and residual effects was used to estimate genetic parameters using REML procedures. The additive genetic variance for tick count ranged from 0.01 to 0.08. The animal permanent  environmental variance ranged from 0.00 to 0.03. Phenotypic variance decreased with increasing mean tick count level while additive genetic variance increased with mean tick count level. The heritability also increased with mean tick count level until a mean tick count level of ³30. The highest heritability estimate obtained in the current study was 0.17 for data with mean tick count level ³25. These results suggest that sufficient genetic variation for tick count exists in the Bonsmara cattle. Genetic selection for tick resistance is feasible even though genetic progress may be slow.Keywords: tick count, variance components, heritability estimates, beef cattle, external parasite

Sire x ecological region interaction in Bonsmara cattle

Die moontlike interaksie tussen vaar en vier ekologiese streke waarin Bonsmara beeste in Suid-Afrika hoofsaaklik voorkom is ondersoek. Geboorte en speenrekords van 43 628 geregistreerde kalwers wat gebore is tussen 1976 en 1997 in 18 kuddes was beskikbaar. Beperkte maksimum aanneemlikheid (REML) prosedures is gebruik in die ontleding. Genetiese korrelasies en verwagte genetiese vordering as gevolg van seleksie is beraam deur dieselfde eienskap (bv speenmassa) as verskillende eienskappe in elk van die vier streke te beskou. Die resultate toon dat vir genetiese evaluasie die drie bosveldstreke as een omgewing beskou kan word. Dit sal egter beter wees om die hoeveldstreek as 'n aparte omgewing te hanteer. Die seleksie van bulle wat op die Hoeveld geteel is met die doel om genetiese verbetering in die Bosveld te bewerkstellig behoort minder effektief wees as die seleksie van bulle wat enige plek in die Bosveld geteel is en andersom. Die resultate bevestig ook weereens dat vaar x kontemporere groep (HYS) interaksie gewoonlik belangriker is as die interaksie tussen vaar en enige vasgestelde streek.The possible interaction between sire and four ecological regions in which Bosmara cattle are mainly found in South Africa was investigated. Birth and weaning weight records of 43 628 registered Bonsmara calves born between 1976 and 1997 from 18 herds were available. Restricted Maximum Likelihood (REML) procedures were used in the analyses. Genetic correlations and expected correlated response to selection were estimated assuming the same trait (e.g. weaning weight) to be a different trait when measured in each of four different regions. The results indicate that for the purpose of genetic evaluation, the three bushveld regions need not be separated, but that it would be advisable to consider the highveld region as a separate environment. Selection of bulls bred on the Highveld for the purpose of genetic improvement in the bushveld regions is likely to be less effective than selection of bulls bred anywhere in the bushveld and conversely. The results have also, once again, confirmed that the interaction between sire and contemporary group (HYS) is usually more important than between sire and any designated region.https://www.sasas.co.za/resources/sa-journal-animal-sciencehj2020Genetic