Diet Mixing and Supplementation Present an Opportunity to Increase the Use of Encroaching Woody Plants by Goats

Along with the woody plant expansion that is predicted to continue at the expense of the grassy layer is the increasing societal demand for animal protein and livestock products. Unless concerted efforts by land users, ecologists, and animal scientists are made to increase the utilization of trees and shrubs as forage, it will be impossible to meet future demand for meat and meat products. We conducted two short-term pen experiments to determine the effects of (1) supplementation with polyethylene glycol (PEG-a polymer purported to bind and neutralize the negative effects of tannins), a high-protein source (soybean meal), and a high-energy source (yellow maize grain) and (2) diet mixing (single-species vs. multispecies diets) on the intake of condensed tannin-rich woody plants (i.e., Searsia lancea, S. pyroides, and Euclea crispa) by goats. While all three forage species were used in the diet mixing experiment (Exp. 2), only E. crispa was used in the supplementation experiment (Exp. 1). Supplementing goats with energy- and protein-rich sources significantly increased the intake of E. crispa (p < 0.05), 713.4 g ± 13.5 and 760 g ± 28.9, respectively, whereas those on the control diet maintained their intake at 540.32 g ± 11.2. Although PEG tended to increase the consumption of E. crispa by goats, the observed increase was not significant (p > 0.05) from that observed in other treatments. In the diet mixing experiment, goats offered a combination of all three forage species attained substantially higher dry matter intakes compared to the goats offered these species individually (p < 0.05). While longer-term field experiments are needed in the African savannas, we postulate from the current results that management strategies that provide animals with (1) a variety of species in the diet vs. monocultures and (2) a combination of nutrient-rich and tannin-rich species may improve the ability of goats to consume chemically defended woody plants.

Effects of garlic supplementation on in vitro nutrient digestibility, rumen fermentation, and gas production

Garlic contains secondary metabolites with antimicrobial properties that can alter nutrient digestibility and rumen fermentation, similar to other antimicrobial products. The objectives of the study were to evaluate the effects of garlic powder and garlic juice on in vitro nutrient digestibility, rumen fermentation, and gas production. The treatments consisted of control with no additives, garlic powder, and garlic juice at 0.5 ml and 1 ml. The digestibility of dry matter, crude protein and neutral detergent fibre were determined after 48 hours incubation. Rumen ammonia nitrogen and volatile fatty acids were determined at 12 hours and 24 hours incubation. The cumulative gas production was recorded periodically over 48 hours. The in vitro dry matter disappearance decreased with 1 ml of garlic juice compared with control. The crude protein degradability in garlic powder and garlic juice was lower than in control. Volatile fatty acids increased in all treatments. Individual volatile fatty acids were significantly different, especially propionate, whereas the acetate to propionate ratio was reduced by garlic juice, and ammonia nitrogen was reduced by garlic powder and 0.5 ml of garlic juice. The cumulative gas production increased significantly with both levels of garlic juice. The addition of garlic juice at 0.5 mL/100 ml could enhance the production of propionate, and reduce the acetate to propionate ratio, implying that the supply of hydrogen for methanogens was limited.

Repellent properties of Rotheca glabrum plant extracts against adults of Rhipicephalus appendiculatus

Background

Rotheca glabrum (formerly known as Clerodendrum glabrum [Verbenaceae]) is used by local communities in the Limpopo Province of South Africa to control ticks on livestock and was selected from the database of the ARC-Onderstepoort Veterinary Institute. Its leaves were extracted using organic solvents ranging from polar to non-polar solvents (methanol, acetone and dichloromethane (DCM)). In addition, the traditional soap-water (infusion) and water-based (decoction) methods were used. The tick repelling activity was determined against the adult stage of the livestock tick Rhipicephalus appendiculatus.

Results

In the tick-climbing repellency bioassay a 30% acetone extract had a significant (p ≤ 0.05) repellent effect against adults of R. appendiculatus. The extract was still active at a lower concentration of 10%. The hexane fraction from the R. glabrum acetone extract had a higher tick repellency activity than the positive controls Amitix and Bayticol at the same concentrations. Unfortunately, the activity decreased after 2.5 h, probably due to volatility of the biologically active compound(s) within the extract.

Conclusion

Attempts were made to isolate the repellent compound from the acetone extract of R. glabrum. The process produced very good results up to a late stage in the bioassay-guided fractionation process. At that point, the repellent activity was lost. When two fractions were combined, the repellent activity was regained. These results provide strong evidence for the existence of a synergisticactivity of different compounds. It may be better to concentrate on extracts that would kill ticks rather than on extracts that would repel ticks.

41 THE EFFECT OF AMBIENT TEMPERATURE ON SPERM MOTILITY DURING LIQUID STORAGE OF VENDA COCK SEMEN AND INDIVIDUAL DIFFERENCES IN SPERM CRYOTOLERANCE

Improving techniques for liquid storage of cock semen can increase the efficiency of AI programs in the poultry industry. The aims of the present study were (1) to compare storage of cock sperm for 24 h at 5 and 25°C and (2) to test the cryotolerance of sperm cell motility in individual Venda cocks. Semen was collected with the abdominal massage method, from 6 indigenous Venda cocks. Cocks were 26 weeks of age and were kept under the same conditions. After macroscopic analysis, semen was pooled and diluted (1:2) with Kobidil+ extender and divided into 3 equal parts. Part 1 was evaluated immediately (0 h), part 2 was stored at 5°C and part 3 was stored at 25°C and evaluated for sperm motility and velocity parameters at 4, 8, 12 and 24 h of storage. For cryopreservation, semen was diluted (1:2) with modified Kobidil+ extender supplemented with 8% of dimethyl sulfoxide. Individual ejaculates were equilibrated at 5°C for 4 h and then loaded into the programmable freezer. Then, semen straws were thawed at 5°C. Sperm motility and velocity parameters were evaluated using the Sperm Class Analyzer® system. Six replicates were done per trial. Data were analysed using the statistical programme GenStat®. Treatment means were separated using Fisher's protected t-test least significant difference (P < 0.05). Total sperm cell motility rate was 87.5% and decreased significantly during in vitro storage and was <31% after 24 h at 25°C. Semen samples stored at 5°C showed a total sperm cell motility rate of above 50% after 24 h. There was a slight linear decrease in the percentage of sperm with progressive motility and rapid velocity as the storage period increased, irrespective of the storage temperature. The rapid and medium motility percentages were higher in fresh semen and significantly decreased (P < 0.05) during the incubation period. There was variation in the total sperm cell motility of fresh and frozen semen among cocks. There was no significant difference in variation in non-progressive and medium percentage (P > 0.05) motility in diluted fresh or frozen sperm cells or in the percentage of sperm with rapid motility in thawed semen. There was variation in <25% of the cocks in total sperm motility rate. In summary, cryopreservation reduced sperm cell motility and velocity rates in all the cock semen donors. We found that cryotolerance of cock sperm does vary among males. Furthermore, the lower temperature 5°C was suitable for semen storage of Venda cocks. This temperature (5°C) could potentially improve methods of semen equilibration before cryopreservation. The study was supported by an Agricultural Research Council Parliamentary Grant, Department of Agriculture Forestry and Fisheries and National Research Foundation-GUN No RT21 and 24000 (NRF). The Germplasm Conservation & Reproduction Biotechnologies (GCRB) group is thanked for their support.

105 CRYOPRESERVATION OF VENDA COCK SPERMATOZOA: EFFECT OF CRYOPROTECTANT FOLLOWING ANALYSIS BY COMPUTER-ASSISTED SPERM ANALYSIS

The choice of ideal permeable cryoprotectant for cock semen equilibration and freezing is critical. The aim of this study was to compare three different cryoprotectants [dimethyl sulfoxide (DMSO), ethylene glycol (EG), and propanediol (PND)] following cryopreservation. The abdominal massaging technique was used for semen collection from 5 Venda cocks. Individual ejaculates were diluted with modified Kobidil+ (mK+) extender (fraction A) at a ratio of 1:2 and equilibrated for 2 h at 5°C. Semen samples of 5 μL were taken at 0, 60, and 120 min and evaluated by CASA for spermatozoa motility parameters (rapid, medium slow, static, NPM and PM) and velocity. Semen was further diluted at 1:1 volume ratio with mK+ supplemented with 8% DMSO, EG and PND (fraction B), and equilibrated for additional 2h at 5°C and evaluated at 60 and 120 min for motility and velocity. Cooled semen were then transferred into 0.25-mL straws and placed into a programmable freezer. The temperature of the chamber was decreased in a stepwise manner, from 5°C to -20°C, at the rate of 1°C/min until it reached the target temperature. The straws were exposed to liquid nitrogen (LN2) vapor and then plunged into LN2 (-196°C). The semen straws were stored into LN2 tank at -196°C. After 3 months of storage, semen straws were thawed at 5°C and evaluated by CASA for spermatozoa motility and velocity. Data were analyzed by ANOVA. There were no significance differences between DMSO and EG regarding the survival and motility rate of frozen/thawed semen; however, these parameters were lower compared with the fresh semen. The PND was not a suitable cryoprotectant to cryopreserve Venda spermatozoa. In conclusion, ethylene glycol was found to be a suitable cryoprotectant to cryopreserve spermatozoa of South African Venda cocks. Department of Agriculture Forestry and Fisheries, NRF,ARC, Department of Science & Technology.

71 COMPARISON OF CRYOPROTECTANTS ON CRYOPRESERVATION OF VENDA COCK SPERMATOZOA

Improving the cryopreservation technique for indigenous fowl semen may contribute to the development of cryogene banks in South Africa. The goal was to identify a cryoprotectant among dimethyl sulfoxide (DMSO), ethylene glycol (EG), and propanediol (PND) that is compatible with survival after freezing of Venda cock spermatozoa. Six Venda cocks were used for semen collection. The abdominal massaging technique was applied for semen collection from cocks. Individual ejaculates were diluted with modified Kobidil+ (mK+) extender (extender A) at ratio of 1:2 (v/v) before freezing, and equilibrated for 2 h. Semen was diluted again at a ratio of 1:1 (v/v) with mK+ plus 8% DMSO, EG, and PND (extender B) and equilibrated for 2 h at 5°C. Semen were then transferred into 0.25-mL plastic straws and placed into a programmable freezer (Planer Kryosave). The temperature of the chamber was decreased in a stepwise manner, from 5°C at a rate of 1°C min–1 until it reached the target temperature of –20°C. Finally, the straws were exposed to liquid nitrogen (LN2) vapor and plunged into LN2 (–196°C). The semen straws were stored in an LN2 tank at –196°C. After 1 week, frozen semen straws were thawed at 5°C for evaluation of spermatozoa survivability and motility rate at 0, 30, 60, and 90 min, using contrast microscopy (20× magnification). Data were analyzed by ANOVA. Spermatozoa live and motility rates were greater before freezing (Table 1) in all groups. There was no significance difference between DMSO and EG with regard to live and motility rates. However, the lowest rates of live and motility spermatozoa were recorded in the PND group. In conclusion, this study demonstrated that the cryopreservation process reduces sperm quality and propanediol was not suitable for cryopreserving Venda cock spermatozoa. Table 1.Comparison of three CPA on cryopreservation of Venda cock semen This study was funded by the South African National Department of Agriculture, ARC, DST-PDP (RT19000), and National Research Foundation (NRF, Grant. no. RT21 and 24000).

Ethnoveterinary medicine practices among Tsonga speaking people of South Africa

Rapid Rural Appraisal methods were used to collate and code the indigenous knowledge on animal healthcare of Tsonga speaking people of South Africa. There was a rapport between local disease names as described by their clinical signs by the farmers and the local veterinary services important disease list. The perceived causes of diseases were physico-biological elements and no reference to ancestral guidance was recorded. Males and old people were more knowledgeable but females and young people did show a certain degree of confidence during general discussions. Plants were more frequently used than other non-conventional remedies with cattle being the most treated animals. Farmers reported using 19 plant species belonging to 12 families. Plants were collected from the wild when needed and no specific storage system was used. They were administered as decoctions or infusions of single plants. These remedies were used not only as alternatives to expensive pharmaceutical products but also because in certain diseases or chronic cases, they were thought to be more efficacious.