South African Journal of Animal Science - latest Issue
Volumes & issues
Volume 47, Issue 1, 2017
Author Voster MuchenjeSource: South African Journal of Animal Science 47, pp 1 –1 (2017)More Less
In the past few years, the South African Journal of Animal Science (SAJAS) has taken great strides in advancing animal science and sustainable use of natural resources. Its impact factor rose from 0.143 (2003) to 0.511 (current). Through the dedication and concerted efforts of the editorial team and reviewers; the average turnaround time for article consolidation has reduced from 190 days (2014) to 53 days (current). Join me in commending the outgoing Editor-in-Chief of SAJAS, Prof. Jannes Van Ryssen, for his outstanding service to the journal. His contributions have greatly improved the quality of the articles published in this journal and the journal itself. We applaud his accomplishments and are grateful that he will continue to be part of the SAJAS team as an honorary editor-in-chief. Since my appointment on the 1st October 2016, the editorial board has been reconstituted, with the appointment of Prof. Este van Marle-Köster (University of Pretoria), Prof. Victor Mlambo (North-West University) and I as the SASAS publication committee. Prof. van Marle-Köster has also been appointed as guest editor of the SAJAS. We welcome the addition of a cohort of internationally recognised experts, such as Dr Tim McAlister (Canada), Dr A. Yakubu, Lafia (Nigeria), Dr Dominika Guzek (Poland), Dr Genaro C. Miranda de la Lama (Mexico) and Dr Arnold Kanengoni (South Africa), to the SAJAS editorial board.
Source: South African Journal of Animal Science 47, pp 2 –6 (2017) http://dx.doi.org/10.4314/sajas.v47i1.2More Less
The patterns of embryonic development in ostriches, especially in the last stage of hatching, are still not well understood. This study examined between 3468 and 3484 dead-in-shell (DIS) eggs with chicks that died between day 35 and day 42 of artificial incubation. Most DIS chicks were positioned correctly with their heads towards the air cell (52.6%). DIS chicks that positioned their heads near the equator of the egg amounted to 46.5%, while a small percentage (0.9%) were positioned with their upper body towards the bottom of the egg. More DIS chicks tended to pip internally near the equator of the egg (37.6%) than DIS chicks that pipped internally through the membranes into the air cell (34.4%). Most DIS chicks had their heads turned in the correct position from left to right (54.4%), though their beaks were mostly positioned towards the air cell (52.9%). The highest percentage of DIS chicks had their feet in the upwards position (52.4%), while 46% had their feet across or below the head. The wings of all DIS chicks were positioned next to the body. Results from the study showed that most of the DIS chicks were roughly in the correct position, but were still unable to hatch. This warrants future research to investigate the reasons that prevent correctly positioned chicks from hatching.
Source: South African Journal of Animal Science 47, pp 7 –15 (2017) http://dx.doi.org/10.4314/sajas.v47i1.3More Less
The use of agricultural by-products has become the central focus in reducing feed costs in pig production. However, there is a need to determine how the gastrointestinal tract of pigs responds when subjected to fibrous ingredients. The objective of the study was to predict villi height and apparent villi surface area from physicochemical measurements of maize cob-based diets. Eighteen growing male pigs (initial bodyweight 14.3 ± 1.20 kg) were used in the experiment. The pigs were penned individually and subjected to diets containing 0 g, 80 g, 160 g, 240 g, 320 g, and 400 g maize cob meal/kg diet. Feed and water were provided ad libitum. Using stepwise regression, bulk density (BD) and neutral detergent fibre (NDF) were the best predictor variables influencing villi height (VH) and apparent villi surface area (AVSA). VH produced quadratic and linear responses with BD and NDF, respectively. The equations are VH = 211.3(BD)2 – 591.0(BD) + 442.4; and VH = 0.03(NDF) + 22.8. Conversely, AVSA produced quadratic and linear responses with NDF and BD, respectively. The equations are AVSA = 0.00036(NDF)2 – 0.012(NDF) +7.25 and AVSA = - 47.12(BD) + 45.03. In conclusion, the BD and NDF of a feed could be used to predict VH and AVSA of growing pigs fed maize cobs.
Evaluation of various feeding programmes on growth performance, carcass and meat qualities of Thai indigenous crossbred chickensSource: South African Journal of Animal Science 47, pp 16 –25 (2017) http://dx.doi.org/10.4314/sajas.v47i1.4More Less
This study was conducted to evaluate the effects of various feeding programmes on growth performance, carcass characteristics, and the meat qualities of Thai indigenous crossbred (50%) Korat chickens to obtain suitable feeding programmes. A total of 480 one-day-old mixed-sex Korat chickens were randomly allotted to four treatments, namely FP1, FP2, FP3 and FP4, with four replicates for each treatment (30 birds per replicate) in a completely randomized design. Chickens in FP1 were fed diets with 21, 19, 17 and 15% crude protein (CP) in periods of 0–3, 3–6, 6–9 and 9–13 weeks old, respectively. Chickens in FP2 were fed diets with 21, 19, 17 and 15% CP in periods of 0–3, 3–5, 5–7 and 7–13 weeks old, respectively. Chickens in FP3 were fed diets with 21, 19, 17, 15 and 14% CP in periods of 0–2, 2–5, 5–8, 8–10 and 10–13 weeks old, respectively. Chickens in FP4 were fed diets with 21, 19, 17, 15 and 14% CP in periods of 0–2, 2–4, 4–6, 6–8 and 8–13 weeks old, respectively. At 13 weeks old, the results showed that Korat chickens fed with FP4 had a higher feed intake, but poorer feed conversion rate (FCR), protein efficiency ratio (PER), and energy efficiency ratio (EER) values than the FP1, FP2 and FP3 treatments. However, the values for bodyweight gain and blood urea nitrogen (BUN) did not differ among treatments. None of the parameters for carcass traits, meat characteristics, and meat qualities revealed differences among treatments, except for the protein content in the thigh meat of chickens fed with FP4, which had a lower value than that of the other treatments. In conclusion, FP3 represented the most beneficial results for reducing feed costs without affecting growth performance, carcass traits, nutrient composition of meat, and meat characteristics of chickens.
Effect of days in feedlot on growth performance and carcass characteristics of Merino, South African Mutton Merino and Dorper lambsSource: South African Journal of Animal Science 47, pp 26 –33 (2017) http://dx.doi.org/10.4314/sajas.v47i1.5More Less
This study investigated the effect of feedlot production on lamb growth characteristics of three common South African breeds: Merino, South African Mutton Merino (SAMM) and Dorper. Lambs were supplied with a balanced diet (16% crude protein, 9.41 MJ ME/kg feed) ad libitum and had free access to water. Lambs from each breed were divided into six groups. One group of each breed was slaughtered every three weeks until 105 days under feedlot production were reached. The weights of the lambs were recorded weekly, along with feed intake, to obtain the individual daily intake, average daily gain (ADG) and feed conversion ratio (FCR) for each lamb. The ADG for the SAMM 2007 and Dorper lambs increased throughout their production period, while that of the SAMM 2008 and Merino lambs tended to decrease with time, although the SAMM 2008 group achieved the highest ADG of 350.2 g/lamb/day of all the breeds. The Dorper and SAMM 2007 lambs had higher FCR (7.52 and 7.58, respectively). The average FCR achieved by the SAMM 2008 and Merino lambs was 5.54 and 5.14, respectively. However, the FCR of Merino and SAMM 2008 lambs increased throughout the production period. The Dorper lambs produced fatter carcasses and therefore exhibited the highest average dressing percentage of 49.7% compared with the SAMM 2007 (48.4%) and 2008 lambs (45.6%), followed by the Merino lambs (43.9%). The results confirm that the Merino is a late maturing breed that is recognised for its wool rather than meat production, and therefore exhibits weaker growth characteristics. The SAMM is a dual-purpose breed that has also been selected for growth and meat production, and therefore exhibits desirable production characteristics, while the Dorper is an early maturing breed that deposits localized fat at an earlier age as it grows, thereby producing fatter carcasses than SAMM and Merino lambs. Therefore, Dorper lambs should be slaughtered at lower live weights so that carcasses are not graded as over-fat.
Source: South African Journal of Animal Science 47, pp 34 –40 (2017) http://dx.doi.org/10.4314/sajas.v47i1.6More Less
Conscious animals typically experience sensory (nociception) and emotional pain, whereas unconscious animals that were minimally anesthetized would experience minimal emotional pain. To determine whether ‘silencing’ the emotional component through a minimally anesthetized model would minimize stress response, and thus improve animal welfare, this study aimed at comparing changes in electroencephalographic (EEG) activities associated with possible noxious stimuli following neck-cut slaughter in conscious non-anesthetized versus minimally anaesthetized Boer cross-bred goats. Ten bucks were randomly assigned to two groups of five animals each, and subjected to neck-cut slaughter when fully conscious (HS) or under minimal anaesthesia (AS) and exsanguinated. The anaesthesia was induced with propofol (5 mg/kg) administered to effect by rapid injection into a cephalic vein and maintained with halothane in 100 % oxygen. Changes in the root mean square (RMS) for each of alpha, beta, delta and theta waves, median frequency (F50) and total power of the EEG (Ptot) were compared in each group before and after neck cut and between groups following treatments. Electroencephalographic parameters did not differ between goats that were fully conscious or slaughtered under minimal anaesthesia. These findings showed that the noxious stimuli from neck cut were present in both conscious and minimally anaesthetized goats. Most importantly, the presence of emotional pain and nociception did not affect the extent of electroencephalographic responses significantly compared with animals that were experiencing nociception only.
Coefficient of standardized total tract digestibility of phosphorus in oilseed meals and distillers dried grains in growing-finishing pigsSource: South African Journal of Animal Science 47, pp 41 –48 (2017) http://dx.doi.org/10.4314/sajas.v47i1.7More Less
This study was conducted to determine the coefficient of total tract standardized digestibility (CTTSD) of phosphorus (P) in oilseed meals and distillers dried grains (DDG) fed to growing-finishing pigs. Twelve barrows (initial bodyweight (BW) ± standard deviation, 52.25 ± 2.57kg) were allocated individually to metabolism cages. The experimental design was a 12 × 8 incomplete Latin square with 12 dietary treatments and eight replication periods. The diets were formulated individually with dehulled soybean meal produced in Korea (SBM-KD), soybean meal produced in India (SBM-I), soybean meal produced in Korea (SBM-K), corn high-protein distiller dried grains (HPDDGs), tapioca distillers dried grains (TDDG), canola meal (CAM), corn germ meal (CGM), copra meal (CM), palm kernel meal (PKM), sesame meal (SM), perilla meal (PM), and a P-free diet. Intake of P was highest in SM and PM. Excretion of P was reduced in y ascending order as HPDDG, TDDG and CGM; SBM-K; and SM and PM. The CTTAD of P was higher in CGM than SBM-K, TDDG, SM and PM. HPDDG and CGM showed greater CTTSD of P than SBM-K, CAM and PM. Digestible concentration of P on CTTSD (CTTSD-P) of P was greater in PM and CAM than the others except for SBM-KD. In summary, PM could be utilized as an alternative feedstuff to SBM, but its usage is regarded only as a source of P. In addition, the results of the current study would provide valuable information for formulating pig feed with precise P utilization in ingredients using mixed diets.
Viability of bull semen extended with commercial semen extender and two culture media stored at 24 °CSource: South African Journal of Animal Science 47, pp 49 –55 (2017) http://dx.doi.org/10.4314/sajas.v47i1.8More Less
The aim of this study was to evaluate the viability of bull spermatozoa diluted with commercial semen extender and two culture media stored at controlled room temperature (24 °C) for 72 hours. Two Nguni bulls were used for semen collection with the aid of an electro-ejaculator. After macroscopic evaluation, semen was pooled and aliquoted randomly into Triladyl, modified Ham’s F10, and TCM-199 culture media, and then stored at 24 °C. Sperm motility parameters, morphology, and viability were analysed with computer aided sperm analysis (CASA) after 0, 24, 48 and 72 hours. The study was replicated four times, and data were analysed using analysis of variance (ANOVA). Triladyl had significantly higher sperm viability rate (41.3%) and total motility rate (96.3%) for 72 hours than modified Ham’s F10 (86.8%; 26.5%) and TCM-199 (76.7%; 25.0%) culture media. Ham’s F10 had higher progressive motility rate (37.8%) than the other extenders TCM-199 (31.7%) and Triladyl (23.4%). There was no significant difference in viability rate between Ham’s F10 (26.5%) and TCM-199 (25.0 %) after 72 hours’ storage at 24 °C. Furthermore, no significant difference was observed in total sperm abnormalities, except for reacted acrosomes and absent tails, between the two Nguni bulls. Nguni semen can be preserved in Triladyl or modified Ham’s F10 and TCM-199 culture media, stored at 24 °C, and stay viable for 72 hours.