Characterization and population genetics of Haemonchus contortus in Merino sheep in Lesotho.

Haemonchus contortus is the most pathogenic and economically restrictive gastrointestinal nematode in the small ruminant industry globally. Morbidity, poor cross-bodily state, and mortality of sheep in Lesotho suggest the presence of H. contortus. The present study investigated the morphological, molecular, and population genetics of H. contortus third-stage larvae infecting sheep in four ecological zones (EZ) of Lesotho. Coprocultures were prepared for larval morphological identification and PCR determination. Larvae were identified morphologically as 100% H. contortus. The Second Internal Transcribed Spacer (ITS-2) gene of the ribosomal DNA of H. contortus isolates in the present study revealed nucleotide homology ranging from 97 to 100% when compared with selected GenBank reference sequences. Pairwise evolutionary divergence among H. contortus isolates was low, with 0.01318 recorded as the highest in the present study. Five haplotypes resulted from 14 Lesotho sequences. Haplotype diversity and nucleotide diversity were 0.76923 and 0.00590, respectively. Genetic differentiation among isolates was low but not statistically significant. An analysis of molecular variance revealed that most molecular variation was distributed within topographic populations at 94.79% (FST = 0.05206, p > 0.05) and 5.21% among populations. There was high gene flow and no definite population genetic structure among Lesotho isolates.

Identification and prevalence of ticks on Merino sheep in Lesotho.

For over a decade, export of wool accounted for 58.3% of agricultural exports from Lesotho. Even though the sheep subsector contributes significantly to the economy, its development is hampered by different constraints. One of the most important constraints of sheep production is poor animal health due to widespread diseases including those caused by ticks. This study aimed to identify tick species parasitizing sheep and to determine whether tick prevalence on sheep was influenced by agroecological zone, sheep age, and seasonality. Ticks were collected from 720 sheep in the four agroecological zones of Lesotho, namely lowlands, foothills, Senqu River Valley, and highlands, during December 2018-May 2019. Ticks were picked from their sites of attachment then taken to the laboratory for identification to species level. No ticks were found on the sheep examined from the highlands and, as a result, this agroecological zone was excluded from further analysis. The following five tick species, with their overall prevalence, were identified: Rhipicephalus evertsi evertsi (38.0%), Rhipicephalus (Boophilus) decoloratus (1.6%), Hyalomma rufipes (1.0%), Otobius megnini (1.0%), and Rhipicephalus appendiculatus (0.3%). Four of the species were hard ticks (Family Ixodidae). The only soft tick species found was O. megnini (Family Agarsidae). Tick prevalence was influenced by seasonality that varied across agroecological zones. Foothills and lowlands had highest tick prevalence in December and January, respectively, and lowest prevalence in February and May, respectively, whereas Senqu River Valley had highest tick prevalence in May and lowest in March. The age of the sheep did not significantly influence prevalence of tick infestation.

Effect of storage time on the quality of cauda epididymal spermatozoa of West African dwarf (WAD) rams.

The objectives of the study were to develop a protocol for preserving Western African Dwarf (WAD) ram cauda epididymal semen that could be applied in preserving and storing the semen of endangered species/genetically valuable animals in case of death and to study the morphometric characteristic of epididymides after refrigerated storage. Thirty testes-epididymides were collected immediately after slaughter from mature WAD rams and transported in ice chest at (4.5-6 °C) to the laboratory. The samples were either processed immediately or stored in a refrigerator at 5 °C for 6, 12, 24, 48 h. The results indicate that the semen motility decreased (P < 0.05) when compared to the control [87.5 ± 2.1% (0 h), to 85.0 ± 1.8% (6 h), 73.3 ± 3.6% (12 h), 53.3 ± 2.5% (24 h) and 50.0 ± 2.9% (48 h)]. The sperm concentration also decreased (P < 0.05) as duration of storage increased (0 h) 157.5 ± 8.2, (6 h) 152.3 ± 5.8, (12 h) 125.3 ± 4.4, (24 h) 106.2 ± 2.9, (48 h) 98.5 ± 3.5. Semen viability decreased as duration of storage increased from the 0 h to 48 h [(P < 0.05; 84.0 ± 1.4%, 82.8 ± 2.2%, 77.3 ± 1.7%, 69.8 ± 1.5%, and 66.5 ± 1.2%, respectively]. Furthermore, there was a decrease (P < 0.05) in percentage of intact acrosome as duration of storage increased [(0 h) 90.7 ± 1.0%; (6 h) 89.3 ± 2.0%; (12 h) 85.5 ± 1.6%; (24 h) 70.0 ± 2.4%; and (48 h) 73.3 ± 2.1%]. The results from this study indicate that epididymal semen of WAD rams recovered and preserved at 5 °C for 48 h may be used for artificial insemination.