Scielo RSS <![CDATA[South African Journal of Animal Science]]> vol. 47 num. 1 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>Editorial</b>]]> <![CDATA[<b>Dead-in-shell positions of near-term ostrich embryos</b>]]> 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. <![CDATA[<b>Relationship between feed characteristics and histomorphometry of small intestines of growing pigs</b>]]> 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. <![CDATA[<b>Evaluation of various feeding programmes on growth performance, carcass and meat qualities of Thai indigenous crossbred chickens</b>]]> 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. <![CDATA[<b>Effect of days in feedlot on growth performance and carcass characteristics of Merino, South African Mutton Merino and Dorper lambs</b>]]> 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. <![CDATA[<b>Electroencephalographic responses to neck cut and exsanguination in minimally anaesthetized goats</b>]]> 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. <![CDATA[<b>Coefficient of standardized total tract digestibility of phosphorus in oilseed meals and distillers dried grains in growing-finishing pigs</b>]]> 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 ± 2.57 kg) were allocated individually to metabolism cages. The experimental design was a 12 χ 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. <![CDATA[<b>Viability of bull semen extended with commercial semen extender and two culture media stored at 24 °C</b>]]> 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. <![CDATA[<b>Physico-chemical quality attributes and fatty acid profiles of pork from Windsnyer and Large White gilts</b>]]> The objective of the study was to assess the physico-chemical pork quality attributes and fatty acid profiles of indigenous Windsnyer (WS) and Large White (LW) gilts. Twelve gilts of each breed were fed similar commercial diets from weaning until slaughter at the age of 21 weeks. The m. longissimus thoracis et lumborum was sampled. Differences in muscle pH values obtained 24 hours post mortem (pH24) were not significant in pork from the WS or LW gilts. Pork lightness 24 hours post mortem (L*24) was significantly lower in WS gilts than in LW gilts. Muscle saturated fatty acids (SFA) were higher in WS gilts than LW gilts. Fat of LW gilts had higher polyunsaturated (PUFA), n-6 fatty acids, n-3 fatty acids and PUFA: SFA ratio than WS gilts. The study showed preferential attributes of pork from LW gilts than from WS gilts. The accrued information could benefit the food industry by assisting researchers and nutritionists to interpret the quality of pork from different pig genotypes for health-conscious consumers. Furthermore, it aids in determining the concern about pork as a cardiovascular risk factor and acts as a planning tool for public-health programmes. <![CDATA[<b>Partial replacement of commercial soybean meal with raw, full-fat soybean meal supplemented with varying levels of protease in diets of broiler chickens</b>]]> A 3 * 3 factorial study was used to evaluate the feed intake (FI), body weight gain (BWG), and feed conversion ratio (FCR) of broilers fed on the test diets. The commercial soybean meal (SBM) was replaced by raw, full-fat soybean meal (RSBM) at 0, 10 or 20%, equivalent to 0, 30 and 60 g/kg of diet, respectively, and the microbial protease was also supplemented in diets at 0.1, 0.2 or 0.3 g/kg, equivalent to ~7500, 15000 and ~22500 PROT/kg of diet, respectively. Microbial phytase (1000 FYT/kg) was uniformly added to each diet, which was fed to six replicate groups, with nine birds per replicate. Samples of test-ingredients and test-diets, after mixing, were also subjected to chemical analysis, prior to being used, to assess the nutritional compositions, particularly anti-nutritional factors. As the result of this study, the analysed concentrations of trypsin inhibitors (TI) in the diets ranging between 1730.5 and 9913.2 TIU/g. Increasing the levels of RSBM in the diets reduced the FI, during 1 to 35 d of age. Except in the starter phase, increasing the level of RSBM had no significant effect on BWG. When protease was added to the diets, the BWG was significantly improved during the periods of 1 - 10 d, 1 - 24 d and 1 - 35 d. Feed efficiency was decreased by increasing the level of RSBM (1-10 d). Neither increasing levels of RSBM nor protease affected the yield of any meat part at d 35. The relative weight of the small intestine at d 10 increased with rising levels of RSBM, but was reduced when protease was added to the diets. In conclusion, commercial SBM could be replaced by RSBM up to 20% in diets for broilers when the test microbial protease is supplemented. <![CDATA[<b>Genetic polymorphism of CSN1S2 in South African dairy goat populations</b>]]> Alpha-s2 casein has a significant influence on protein content in goat milk, and the technological properties important for cheese processing. Specific alleles (A, B, C, E and F) of the alpha (a)s2-casein gene (CSN1S2) result in higher protein, casein and fat content, and improved coagulation properties, which are useful for improved cheese making. The aim of this study was to investigate the polymorphism and genetic variation of CSN1S2 in South African dairy goats, using DNA sequencing technology. Sixty dairy goats (20 Saanes, 20 British Alpine, and 20 Toggenburg) and 20 meat-type goats were sequenced with four primers to distinguish among the seven known alleles for a s2-casein. A total of four alleles (A, B, C and F) for CSN1S2 were observed among the dairy- and meat-type populations with ten genotypes across the populations. The A allele and the AA genotype were the most frequent across the populations, with the favourable AC genotype being the most frequent (0.300) in the Saanen population. Two unique genotypes were detected in the Toggenburg (BB and BF) and one in the meat-type goats (CF). The results indicate moderate genetic variation for a s2-casein in the South African goat populations (42.3-63.6%). Low positive F ST values suggest limited inbreeding. This study confirmed the presence of favourable alleles in the South African goat populations, indicating room for genetic improvement using directional selection for favourable genotypes. <![CDATA[<b>Pre-slaughter effects on bleed-out times and some behavioural and physiological responses of Nguni and non-descript steers</b>]]> The effect of loading, transportation, lairage and slaughter conditions on bleed-out times, behavioural and physiological responses of Nguni and non-descript steers reared extensively on natural pastures was investigated. Twenty Nguni (NG) and 20 non-descript (ND) steers were loaded and transported 120 km from the farm to the abattoir in two groups (TG1 and TG2), each comprised of both genotypes. Some environmental conditions and steer behavioural responses were monitored during on- and off-loading, transportation, lairage, and stunning. Trained observers recorded the posture of the steers during transportation, time-budgets during lairage, avoidance-related behaviour, and vocalization scores at stunning were recorded. The steers were slaughtered in four groups (SG1, SG2, SG3 and SG4) and the number of attempts to stun each steer was recorded. Blood samples were collected from each steer during exsanguination for cortisol, glucose and lactate analysis. It took less time to load (370 s) and off-load (602 s) TG1 than TG2 (420 s and 782 s, respectively). All steers were standing throughout transportation and during the lairage observation period. Avoidance-related behaviour and vocalization in the stunning box were not influenced by genotype. The TG1 steers showed more avoidance behaviour (63.2%) and higher cortisol (140.6 ± 14.50 nmol/L) and lactate (12.4 ± 0.83 nmol/L) levels than TG2 (23.9%; 92.8 ± 15.38; 9.0 ± 0.88, respectively). All SG2 steers showed minimal avoidance behaviour with higher cortisol (175.9 ± 17.24 nmol/L) and lactate (13.5 ± 1.12 mmol/L) levels than other groups. Generally, cortisol and lactate levels were positively correlated (r = 0.70). The 5% vocalization recorded was observed from ND steers, TG1 and SG2. In conclusion, steers of different genotypes displayed similar behavioural and physiological responses to identical pre-slaughter conditions that they were exposed to. <![CDATA[<b>In situ ruminal degradability of protein feeds with distinct physical forms: a metaanalysis</b>]]> In ruminant livestock, rumen undegradable protein (RUP) derived from the diet and microbial protein synthesized in the rumen are essential for animal survival, maintenance, growth, production, and reproduction. RUP is influenced by diet composition, physical form, and ruminal metabolism. Here, we aimed to evaluate the ruminal degradability of protein feeds with different physical forms (meal versus grain) through a meta-analysis study. A database, composed of 45 treatments from 12 studies carried out in Brazil, was evaluated to compare the degradability of soybean, sunflower, canola, and flaxseed grains with the meal forms of soybean, peanut, sunflower, cottonseed, and corn gluten. The degradation parameters of dry matter did not differ significantly between meals and grains. However, the effective degradability of crude protein at a passage rate of 2% per hour was higher in meals than in grains. Overall, it was concluded that meal protein might be more degradable in the rumen of animals on an energy intake lower than the maintenance. <![CDATA[<b>Effects of drying procedures on chemical composition and nutritive value of alfalfa forage</b>]]> The effects of various drying procedures of alfalfa forage were evaluated on chemical composition, in vitro neutral detergent fibre (NDF) and dry matter (DM) digestibility, in situ DM, organic matter and crude protein (CP) degradability. The alfalfa had been harvested in the spring growth (early bud and flowering) and first regrowth (late bud and late flowering) periods. The samples were dried at 30 °C (T30), 40 °C (T40), 50 °C (T50), 60 °C (T60) and 100 °C (T100) in a forced-air oven or frozen for one month and then freeze-dried (TFD) or oven-dried at 50 °C (TFREE). Another drying procedure included pre-treatment by heating in a microwave oven (TMO) or in a forced-air oven at 100 °C for 1 hour (T100+50) and then oven-dried at 50 °C. The freeze-drying method was chosen as a reference method. Freeze-dried samples had the lowest NDF, acid detergent fibre (ADF), acid detergent lignin (ADL), neutral detergent insoluble protein (NDIP) and acid detergent insoluble protein contents (P <0.05). Additionally, freeze-dried products had the highest CP, in vitro true digestibility of DM and CP degradability values (P <0.05). There was no added benefit of the TMO in the chemical composition, in vitro digestibility or in situ degradation compared with T50. This study showed that T50 can yield chemical composition, in vitro and in situ results that are similar to those obtained with the freeze-drying method and that this procedure is useful for forage analyses and evaluation. <![CDATA[<b>Relationship between sperm plasma membrane integrity and morphology and fertility following artificial insemination</b>]]> 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 x 10(9) 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. <![CDATA[<b>Isolation of total ribonucleic acid from fresh and frozen-thawed boar semen and its relevance in transcriptome studies</b>]]> The main objective of this study was to isolate high-quality total ribonucleic acid (RNA) from raw fresh semen and frozen-thawed boar semen, using a protocol comprising the conventional TRIzol assay and a membrane-based technique, the PureLink RNA mini kit. Bioanalyzer profile revealed that the sperm RNA size distributions comprised mainly intact RNA ranging from 1500 to 1800 bp, without any detectable residual genomic deoxyribonucleic acid (DNA) or 28S ribosomal RNA (rRNA). Spectrophotometric quantifications of the total RNA yielded 1.64 to 2.44 μg/10(6) spermatozoa, irrespective of the sperm source. The TRIzol/PureLink protocol allowed the isolation of high-quality intact RNA from boar spermatozoa, which is required for transcriptome analysis on high-throughput RNA-sequencing (RNA-Seq) data. Such an approach is relevant to identifying sperm messenger RNA (mRNA transcripts) that are associated with boar semen freezability.