Scielo RSS <![CDATA[South African Journal of Animal Science]]> vol. 48 num. 6 lang. pt <![CDATA[SciELO Logo]]> <![CDATA[<b>Influence of dietary supplementation of ginger powder at different levels on growth performance, haematological profiles, slaughter traits and gut morphometry of broiler chickens</b>]]> The present investigation was performed to determine the impact of the dietary inclusion of ginger powder (Zingiber officinale) on the growth performance, immune response, slaughter traits, blood biochemistry and gut morphology of broiler chickens. One hundred and eighty unsexed broiler chicks (Avian 48) were randomly allocated to four equal groups (45 birds each) (G1, G2, G3 and G4), and each treatment had three replicates (15 birds/replicate). The G1 group was fed with basal diet, G2, G3 and G4 were received the basal diet plus 2 g/kg, 4 g/kg and 6 g/kg ginger powder, respectively. The trial lasted for six weeks. The results demonstrated a significant decrease in the final bodyweight of G4 compared with those of G2 and G3. However, total feed intake improved in G2 and G3 and decreased in G4. The lowest feed conversion ratio (FCR) was observed in chicks of G3, followed by that of G2. At 42 days old, the ginger-supplemented groups showed significant increases in hemagglutination inhibition (HI) titre against Newcastle Disease virus. Significant increases in the leucocyte count (WBCs) and serum total protein were noticed only in G4, and cholesterol and high-density lipoprotein (HDL) levels decreased significantly in G4. In addition, the serum very-low-density lipoprotein (VLDL) and triglyceride levels decreased significantly in the ginger-supplemented groups compared with G1, and the abdominal fat percentage significantly decreased in the G3 and G4 groups. Additionally, the ginger-supplemented groups showed higher villus lengths and greater crypt depths than the control group. Supplementation with ginger powder at a moderate level up to 4 g/kg diet has beneficial effects on growth performance, and up to level 6 g/kg diet improves histological gut parameters and hypolipidemic properties of broilers. <![CDATA[<b>pH measured 24 hours post mortem should not be regarded as ultimate pH in pork meat quality evaluation</b>]]> The aim of this study was to compare the diagnostic values of two methods in pork meat quality evaluation, that is, Method I: pH1 and pH24 and Method II: electrical conductivity (EC2) and pH24, which included pH24, and their modifications, that is, Method III: pH1 and pH48 and Method IV: EC2 and pH48, which included pH48 measurement. Five meat quality classes, namely reddish-pink, firm and non-exudative (RFN), high quality (HQ), pale, soft and exudative (PSE), dark, firm and dry (DFD) and acid meat (AM) were assessed in four even-numbered genetic groups of 40 fatteners each, namely (LxY)xD-A, (LxY)xD-EB, (LxY)xH and (LxY)x(DxP). The change of diagnostic method and therefore pH time measurement from 24 hours to 48 hours post mortem caused a major increase in the percentage of acid meat (AM) that was diagnosed. Most differences were observed in (LxY)xH fatteners, namely 77.5% between Methods I and III and 75% between Methods II and IV. This increase in AM frequency indicates that as a result of significant changes in the post-mortem metabolism that occur in the meat ageing process pH48 should be regarded as ultimate pH (pHu). <![CDATA[<b>Effect of zinc and probiotics supplementation on performance and immune organs morphology in heat stressed broilers</b>]]> The dietary supplementation of trace minerals and probiotics has long been practiced to reduce the harmful effects of high environmental temperature in poultry. The study aimed to assess the effect of single or combined supplementation of ZnSO4●H2O and probiotic (Protexin®) on the growth performance, gut biometry and immune organs histomorphology in broilers reared under cyclic heat stress. For this purpose, 280 day-old broiler chicks were randomly divided into seven groups designated as control (basal diet), HS (heat stress + basal diet), HS-Zn30 (HS + 30 mg ZnSO4●H2O/kg feed), HS-Zn60 (HS + 60 mg ZnSO4●H2O/kg feed), HS-Pro (HS + 0.1 g Protexin®/kg feed), HS-Zn30-Pro (HS + 30 mg ZnSO4●H2O/kg feed + 0.1 g Protexin®/kg feed), and HS-Zn60-Pro (HS + 60 mg ZnSO4●H2O/kg feed + 0.1 g Protexin®/kg feed). Each group consisted of five replicates (8 birds per replicate). The birds were fed on starter (0 - 21days) and grower (22 - 42 days) diets. From day 22 onwards, the birds were exposed to cyclic heat stress (temperature and relative humidity at 35 ± 1 °C and 75 ± 5% respectively) for 8 hours. The results revealed that birds exposed to heat stress showed significant decrease in body weight (BW) and increase in feed conversion ratio (FCR) compared to the control group. The dietary supplementation of ZnSO4●H2O and probiotic either singly or in combination improved BW and FCR throughout the experimental period in heat-stressed broilers. Area of lymphatic nodule and lymphoid follicle in caecal tonsils and bursa of Fabricius increased in HS-Pro, HS-Zn30-Pro and HS-Zn60-Pro groups compared to HS group. In conclusion, zinc and probiotics combination partially improved performance and immune organs histomorphology in heat-stressed broilers. <![CDATA[<b>The comparison of three media on the <i>in vitro </i>maturation rate of pig oocytes</b>]]> In vitro embryo production in pigs remains a challenging obstacle, given the high rate of polyspermy following in vitro fertilization. Improving the efficiency of successful in vitro maturation, which leads to sequential in vitro fertilization and culture, augments the need for modern biotechnologies in pig farming systems, and subsequently conserves germplasm, that is, embryos to be used in future breeding programs. Thus, in this study the effects were compared of North Carolina State University-23 (NCSU-23), North Carolina State University-37 (NCSU-37), and epidermal growth factor (EGF/TCM-199) media on pig oocyte maturation rate and subsequent polar body formations in vitro. Ovaries were collected from a local abattoir in a controlled temperature of 39 °C. The oocytes were aspirated with an 18-gauge needle. Oocytes surrounded by a uniform complex-cumulus mass were selected. A total of 284 oocytes were allocated to the study, and were incubated with 5% CO2 at 39 °C for 48 hours. In vitro maturation rate was observed by checking the presence of expanded cumulus-oocyte complex (COC) and polar body formations under a light microscope. The maturation rate and polar body formations were significantly higher in NCSU-37 with 85.9% and 81.9%, respectively. However, there were no significant differences in EGF and NCSU-23 media as 77.1%; 72.5% and 77.1%; 72.7% were obtained for maturation rate and polar body formations, respectively. In conclusion, EGF and NCSU-23 had lower rates of maturation and meiotic development owing to their dissimilarities in composition. However, NSCU-37 rendered the highest results because the composition of the media contained beneficial constituents, that is, gonadotropins. New assisted reproductive programs may be important for commercial pig farming systems, as this may facilitate innovative ways of production. <![CDATA[<b>Pig diet with bioactive compounds influences quality of meat and smoked ham</b>]]> The application of novel meat sources to the production of traditional smoked premium ham was evaluated. Various feeding strategies were designed for 90 Duroc x (Duroc x Landrace) pigs. The experiment was conducted to investigate the effects on the quality of meat and smoked ham when supplementing the diet of slaughter pigs with linseed oil and rapeseed oil and with the addition of vitamin E. Proximate composition, pH, texture and colour parameters of the quadriceps femoris muscles (raw pork and pork ham) were determined. The multivariate analysis of these traits demonstrated that the 3% addition of linseed oil to pigs' diet caused a decrease in the fat content in meat, and in higher meat tenderness and protein content. Diet supplementation with 3% linseed oil caused a significant increase in the technological yield of ham production (20.3%), but only in products with high fat content (8.30%). Data allowed the authors to conclude that diet supplementation with 3% linseed oil, coupled with 100 mg vitamin E, is the best form of supplementing a diet for fatteners that are reared in compliance with the rigorous principles of the pork quality system. <![CDATA[<b>Determination of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in livestock feeds</b>]]> The objective of this study was to examine the levels of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in livestock feeds (calf starter, dairy cattle, fattening cattle, calf growth, lamb starter, lamb growth, dairy sheep, fattening sheep, chick, broiler and layer hen feeds) and feed raw materials (wheat, cottonseed pulp, wheat bran, maize, barley, lentil, wheat straw, bean straw, pea straw and meadow grass). PFOA and PFOS concentrations of 30 livestock feeds, 24 raw feed materials, 9 poultry feeds and 10 water samples were determined by LC-MS/MS. The findings indicated that all the evaluated livestock feeds and feed materials contain perfluorinated compounds. Poultry, cattle, feed raw materials and sheep feed samples were examined for PFOA concentrations and for PFOS concentrations, cattle, poultry, sheep and feed raw materials samples were examined. The highest PFOA concentrations were found in layer hen feed (7.55 μg/kg), dairy cattle feed (6.75 μg/kg) and fattening cattle feed (6.53 μg/kg) respectively. The highest PFOS levels were found in layer hen feed (0.882 μg/kg), calf feed (0.833 μg/kg) and dairy sheep feed (0.830 μg/kg). <![CDATA[<b>Rumen characteristics and feed utilization in goats fed with biologically treated oil palm fronds as roughage in a total mixed ration</b>]]> Six male crossbred (Thai Native x Anglo Nubian) goats, 33.5 ± 1.7 kg body weight (BW), were randomly assigned to a 3 x 3 replicated Latin square design to investigate the effects of fungal-treated oil palm fronds (FTOPF) on feed intake, digestibility, ruminal fermentation and nitrogen utilization. The treatments were untreated oil palm frond (UOPF; T1), fungal treated oil palm frond (FTOPF; T2) and fungal treated oil palm frond with urea 1% (FTOPFU; T3). The results revealed that voluntary feed intake was not significantly different among treatments, while digestion coefficients of nutrients (DM, OM, CP, NDF, and ADF) increased significantly with FTOPF. However, the mean ruminal temperature, pH, NH3-N, blood urea-nitrogen and amount of N absorbed and retained were similar among treatments. In conclusion, FTOPF could be included in total mixed rations without any adverse effect on feed intake, digestibility and rumen fermentation efficiency, suggesting that FTOPF could be used potential as an alternative roughage source for ruminants. <![CDATA[<b>Prediction of foal individual primal cuts yield using video image analysis</b>]]> The aim of this work was to use video image analysis (VIA) technology to predict the individual primal cuts of the equine carcass. For this study, a total of 42 foal carcasses were dissected into eight primal cuts (shoulder, top blade, chuck tender, chuck, neck, blade, fore shank and brisket) from the forequarter (FQ) and eleven primal cuts (full plate, loin, tenderloin, topside, eye of round, hind shank, knuckle, flank steak, tri-tip, silverside and heel of round) from the hindquarter (HQ). The proportion of primal cuts in the total carcass ranged from 0.27% to 4.84% for the blade and shoulder in the FQ, and from 0.97% to 8.60% for the heel of round and full plate in the HQ, respectively. The neck and fore shank were the cuts for which the estimation models were most accurate in the models. These included cold carcass weight (CCW) and VIA measurements obtained in both views and had a prediction to deviation (RPD) values of 1.85 and 1.90, respectively. On the other hand, the prediction of the topside cut was the one that presented high accuracy (k-fold-R² = 0.829) and precision (RMSEcv = 0.23%) with a RPD of 2.85, which suggests a very good predictive ability of the model. Finally, it can be concluded that it is possible to explain the variation of the primal cuts yield in foals with CCW and VIA measurements, and to use this technique as a prediction tool. <![CDATA[<b>The effect of crude protein intake on sperm quality of young and old male broiler breeders</b>]]> This experiment compared fertility of male broiler breeders with different crude protein (CP) intakes from diets containing 9.7%, 11.7% and 13% CP from 27 to 60 weeks of age (in two phases) and in a different group of birds from 52 to 60 weeks of age. This was to assess fertility of males with different CP intakes, as well as comparing fertility in older birds having been fed different protein intakes throughout production to those on a commercial ration for most of production. Sperm concentration and sperm mobility were assessed, as well as the number of points of hydrolysis in the inner-perivitelline membrane of eggs from commercial egg-type hybrids after insemination, which was used to predict egg fertility. There was no response to CP intake observed in sperm concentration or sperm mobility at any age. A positive effect of CP intake was observed in egg fertility towards the end of the production phase. While broiler breeder producers make use of separate sex feeding, the female ration is often fed to males in the appropriate amounts to achieve growth according to the target for males. However because it would be cheaper to include less CP in the ration, the effect of CP on breeder fertility is important. This experiment showed that reducing CP to 117 g/kg in male broiler breeder rations fed throughout the production phase had minimal negative effects on sperm quality, however, increasing CP intake towards the end of production may positively impact egg fertility. <![CDATA[<b>Forage quality and performance of sheep in Massai grass pastures managed at pre-grazing canopy heights</b>]]> The objective of this study was to evaluate the effects of pasture height at pre-grazing of Massai grass on the quality of available forage, forage intake and the performance of lambs raised for meat production. The treatments consisted of four pre-grazing canopy heights (35, 40, 45 and 50 cm). Pastures were managed by the intermittent stocking method and 32 sheep were used. Dry matter intake (DMI) was estimated by Lipe® indicator. Green forage allowance was not affected by pre-grazing heights. There was no effect of heights on the chemical composition of the stem or the leaf blades, except for crude protein content of leaf blades, which showed an inverse linear effect. Grazing time had a quadratic response in function of canopy height. The minimum point was at 42.6 cm, with 502.9 min/day. DMI increased linearly with increasing pasture height. Average daily weight gain (ADG) and stocking rate (SR) responded linearly to pre-grazing heights. Weight gain per hectare was not affected by height as a result of the compensation between SR and ADG. The increase from 35 to 50 cm in Massai grass canopy height reduces its nutritional value and individual performance and increases DMI of sheep intended for meat production. <![CDATA[<b>Growth performance, fatty acid profile and lipid oxidative stability of breast muscle in chickens fed probiotics and antibiotics or their mixture</b>]]> This study assessed the effects of dietary supplementation of probiotics, antibiotics and an antibiotic-probiotics mixture on growth performance of broilers, and the fatty acid profile and oxidative stability of broiler breast muscle. A total of 480 one-day-old broiler chicks (Cobb 500) were assigned to four treatment groups and fed for 42 days. The basal diet served as control treatment (Diet 1), while chicks assigned to Diets 2, 3 and 4 were fed the basal diet with the addition of 0.1 mg/kg of an antibiotic growth promoter (AGP), a commercial probiotic 5 g/kg or the AGP (0.1 mg/kg) + the commercial probiotic (5 g/kg), respectively. Feed intake, weight gain and feed conversion ratio were determined. Fatty acid (FA) profile and lipid oxidative status were monitored at 1 and 7 days post mortem. The results showed no significant difference in average bodyweights among the treatments. However, birds fed Diets 3 and 4 had significantly lower feed conversion ratios and feed intake than the other treatments. At day 7 post mortem, the lipid oxidation in breast meat was significantly lower in Diet 3 compared with the other diets. The meat of the birds fed Diet 3 had lower oleic acid, but higher palmitic acid concentrations at 1 day post mortem. At 1 day postmortem the polyunsaturated fatty acid to saturated fatty acid (PUFA : SFA) ratio was significantly lower in the breast muscle of birds fed Diet 3 compared with those fed Diets 1 and 4, but increased at 7 days postmortem. It could be concluded that probiotics supplementation showed high potential to improve oxidative stability, thereby increasing the shelf life of chicken meat. <![CDATA[<b>Dried brewers' grain as a replacement for soybean meal on nutrient digestibility and rumen parameters of cattle</b>]]> The objective of this study was to determine the effect of replacing soybean meal with dried brewers' grains (DBG) in intake and digestibility of the nutrients and the ruminal parameters of cattle. Four ruminal cannulated Jersey oxen with initial body weight of 662.7 ± 85.5 kg were distributed in a 4x4 Latin square design. The treatments were levels of 0%, 33%, 66% and 100% DBG replacing soybean meal in the diet. Dry matter (DM) and crude protein (CP) intake were not influenced by the treatments. There were linear increases in ether extract (EE), neutral detergent fibre (NDF) and acid detergent fibre (ADF) intakes because of higher levels of these nutrients in diets with DBG. Non-fibre carbohydrate (NFC) and total digestible nutrient (TDN) intake showed a decreasing linear effect. Dry matter and NFC digestibility decreased linearly with rising DBG levels, while EE, CP, NDF and ADF digestibilities were not affected. Ruminal pH was not influenced by DBG levels in the diet. There was a quadratic effect in ammonia nitrogen (NH3-N) concentration in the rumen, with the maximum occurring at a level of 36.7% DGB. The replacement of soybean meal with DBG in cattle diets did not alter DM intake and ruminal pH, but reduced TDN intake. <![CDATA[<b>Weaning-induced cell cycle arrest through up-regulation of p21 and p27 in the jejunum of piglets</b>]]> This study was aimed at investigating the effects of weaning on jejunal redox status, morphology and expression of cell cycle regulators in piglets. A total of 120 new-born piglets from 12 litters were divided into two groups: the control (suckled normally) and weaning group (weaned at day 21). Six piglets from each group were slaughtered at day 22, day 25 and day 28. Results showed that weaning increased the serum hydrogen peroxide (H2O2) and malondialdehyde (MDA), decreased inhibitory hydroxyl radical (IHR) concentrations and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities at day 25. Furthermore, the jejunal nitric oxide (NO) level was increased at days 22 and 28, while H2O2 concentrationwas increased at days 22, 25 and 28. Results of jejunum morphology showed weaning decreased villous height and width, and increased crypt depth at day 25. Relative mRNA and protein expression showed that Smad4 was decreased at day 25 and then increased at day 28. The expression of p21 and p27 were significantly increased by weaning at days 25 and 28, but cyclin D and cyclin E showed no significant differences compared with control group. In conclusion, weaning increased the serum and jejunal reactive oxygen species (ROS) production, inhibited jejunum development and cell cycle progression through down-regulation of Smad4 and up-regulation of p21 and p27 of piglets, which further explained weaning-induced stress syndrome. <![CDATA[<b>Effect of quercetin supplementation on the growth, feed efficiency and serum hormone levels of New Zealand White rabbits</b>]]> Meat rabbits could provide a new avenue for agricultural development in South Africa, and flavonoids may be able to improve their live performance. This study investigated the effects of quercetin dihydrate (0 and 2 g/kg feed) on the growth parameters and serum-free triiodothyronine (fT3), free thyroxine, somatotropin, and cortisol levels of growing rabbits. It also provides the first growth and feed conversion ratio (FCR) data for South African New Zealand Whites. Control (Ctrl) and quercetin-supplemented (Qrc) diets were provided to 34 (16 male, 18 female) and 32 (15 male, 17 female) rabbits, respectively, from 5 to 12 weeks old. Live performance was measured weekly, and serum hormone levels were determined at 11 weeks old. Overall, the rabbits performed well for live weight and growth rate, growing from 1052 ± 13.4 g to 3192 ± 45.3 g (5 - 12 weeks). Females had higher cortisol levels than males, as found for other species (female = 10.9 ng/mL, male = 3.89 ng/mL). Qrc rabbits tended to have a higher overall FCR than Ctrl rabbits (Ctrl = 3.83, Qrc = 4.01), possibly due to lower feed digestibility, and had smaller sex differences in growth and FCR than Ctrl rabbits, possibly owing to xenoestrogenic activity. They also tended to have higher fT3 levels than Ctrl rabbits (Ctrl = 3.62 ng/mL, Qrc = 4.98 ng/mL), possibly owing to the inhibition of binding to transthyretin. However, it does not seem that the provision of quercetin is commercially justified for improving the live performance of rabbits. <![CDATA[<b>Supranutritional supplementation of vitamin E influences mitochondrial proteome profile of post-mortem <i>longissimus lumborum</i> from feedlot heifers</b>]]> Supplementation of vitamin E improves beef colour stability by minimizing lipid oxidation-induced myoglobin oxidation. Mitochondria affect myoglobin redox stability, and dietary vitamin E influences mitochondrial functionality in skeletal muscles. Nonetheless, the influence of vitamin E on the mitochondrial proteome of beef skeletal muscles has yet to be investigated. Therefore, the objective of this study was to examine the effect of dietary vitamin E on mitochondrial proteome of post-mortem beef longissimus lumborum (LL) muscle. Beef LL muscle samples (24 hours post-mortem) were obtained from the carcasses of nine (n = 9) vitamin E-fed (VITE) (1000 IU vitamin E for 89 days) and nine (n = 9) control (CONT) (diet without supplemental vitamin E) heifers. The mitochondrial proteome was analysed using two-dimensional gel electrophoresis and mass spectrometry, and nine differentially abundant spots were identified. All the differentially abundant spots were over-abundant in CONT, and the proteins were electron transport chain enzymes (NADH dehydrogenase iron-sulphur protein 8, NADH dehydrogenase flavoprotein 2, and cytochrome c oxidase subunit 5B), metabolic enzymes (succinate-CoA ligase (ADP-forming) subunit beta; dihydrolipoyllysine-residue succinyltransferase component of 2-oxoglutarate dehydrogenase complex; pyruvate dehydrogenase protein X component), and enzymes involved in ATP regeneration (creatine kinase S-type). The low abundance of these proteins in VITE may decrease mitochondrial activity, resulting in low oxidative activity. These findings suggest that the strong antioxidant activity of vitamin E leads to less expression of mitochondrial oxidative enzymes in beef skeletal muscles. <![CDATA[<b>Effect of natural zeolite on live weight changes, ruminal fermentation and nitrogen metabolism of ewe lambs</b>]]> The objective of this study was to evaluate the effects of natural zeolite on the performance and nitrogen metabolism of Rambouillet ewe lambs. Forty Rambouillet ewe lambs with an initial weight of 41.06 ± 3.9 kg were randomly assigned to one of four experimental diets, namely 0, 20, 40 and 60 g of natural zeolite (Comercializadora Omega® México) per kg dietary dry matter in a completely randomized design and sixteen ewe lambs were used in a 4 x 4 Latin square metabolism study. Performance was not modified by natural zeolite levels in the diet, and daily gain showed a quadratic response. Ammonia concentration at 8 and 12 hours increased linearly with zeolite. Zeolite increased ruminal pH linearly at 8 and 12 hours. Acetate and butyrate presented a quadratic response, and total ruminal volatile fatty acid concentration was linearly increased by zeolite. Nitrogen retention showed a linear and quadratic response to zeolite. The estimated fractions of protein digested in the small intestine, when rumen-fermentable energy was limiting (PDIE) and when rumen-fermentable nitrogen was limiting, showed a linear and quadratic response to zeolite. PDIE was positively correlated (r = 0.96) with average daily gain. <![CDATA[<b>Palm kernel expellers as an alternative ingredient in growing pig diets</b>]]> This study evaluated the effects of palm kernel expellers in growing diets on growth performance, nutrient digestibility, and carcass and meat quality characteristics of growing-finishing pigs. A total of 88 growing pigs were randomly assigned to two dietary treatment groups. The control diet (CON) was a typical growing or finishing diet based on corn-soybean meal, and the treatment diet (PKE) was formulated by replacing CON with 20% palm kernel expellers. The PKE-CON group was fed the PKE diet during the growing period (six weeks) and the CON diet during the finishing period (12 weeks). The CON-CON group was fed the CON diets during both growing and finishing periods. The PKE-CON group showed significantly depressed growth performance and lower nutrient digestibility than the CON-CON group during the growing period. However, after feeding the typical finisher diets during the finishing period, the PKE-CON group showed no difference in growth performance in comparison with the CON-CON group during both the finishing and overall experimental periods. In addition, carcass and meat quality characteristics were not significantly different between the PKE-CON and the CON-CON groups. The results of this study imply that palm kernel expellers can be an alternative ingredient in the growing diets of growing-finishing pigs if the combined feeding strategy (PKE for the growing period and CON for the finishing period) is used. <![CDATA[<b>Determination of vitamin B9 levels in the milk of Brown Swiss and Simmental cows using the ELISA method</b>]]> The aim of this study was to determine the levels of folic acid in Brown Swiss and Simmental cows' milk by the competitive ELISA method. Brown Swiss and Simmental cows' milk samples were collected from two dairies between February and August 2017 (20 samples from Brown Swiss and 22 samples from Simmental). The average level of vitamin B9 in Brown Swiss milk was approximately 3.27 ± 1.23 μg/100 g, while for Simmental it was around 2.99 ± 0.88 μg/100 g. In the milk mixture, the mean folic acid level was 3.13 ± 1.07 μg/100 g. There was no statistical difference between breeds in terms of folic acid levels in cow's milk. It was concluded that milk is not a sufficient source to meet the daily folic acid needs of adults in Turkey. <![CDATA[<b>Effects of non-genetic factors on the inter-calving period of Nguni cows in South Africa</b>]]> The purpose of this study was to evaluate the effect of geographical regions of South Africa on the inter-calving period of Nguni cows. Data of Nguni cows (n = 26 681) from 427 Nguni breeders in the Savannah and the Grassland Biomes were statistically analyzed to establish the impact of non-genetic factors on the inter-calving period (ICP) of these cows. Cows with an ICP of less than 315 and above 730 days were removed from the dataset before analysis, to comply with Nguni breed standards. Dam age was included as a covariant. The ICP increased slightly up to 48 months of age, after which a decline was noticed up to the age of 108 months. Cows in the Savannah Biome had a shorter ICP than those studied in the Grassland Biome. Within the Savannah Biome, the ICP of cows was significantly shorter in the Eastern Kalahari Bushveld bioregion than in any other bioregion, while in the Grassland Biome the ICP was significantly shorter for cows calving in the Drakensberg and the Dry Highveld bioregions. In terms of seasons, the ICP of cows bred in spring and summer was significantly shorter than that of cows bred in autumn and winter. Categorization of cows in year groupings indicates significant year effects. <![CDATA[<b>Application of immunocastration in a commercial Dohne Merino ram flock before weaning</b>]]> The influence of pre-weaning immunocastration on the growth, incidences of reaction to vaccination, serum testosterone concentration and slaughter performance of ram lambs was determined and compared to that of physically castrated lambs. Immunocastration was performed using two doses of 2 mL Improvac® administered subcutaneously in the shoulder, alternating sides per vaccination, using a Sterimatic® needle guard system. The first vaccination was administered to 50 lambs with an average weight (± SD) of 16.0 ± 3.05 kg, and the second vaccination was carried out six weeks later, when the lambs weighed on average (± SD) 20.5 ± 4.11 kg. An additional 50 lambs were physically castrated using elastrator bands at the same time as the primary vaccination given to the immunocastrates. Data were collected during four sessions over the 25-week period, at time points which fitted into the normal management activities of the commercial operation (Weeks 1, 6, 16 and at slaughter). During these sessions, all lambs were weighed, and blood samples were collected from immunocastrates. The immunocastration injection site was also scored for adverse reactions. Immunocastration was successful in preventing testosterone secretion for the duration of the trial and no differences were reported regarding weight gain or slaughter performance between the treatments. The Sterimatic® and Stericap® system, as used in this study, proved to be an easy-to-use and safe system for the commercial administration of Improvac®, with no adverse reactions to vaccinations recorded at the injection sites. Pre-weaning immunocastration in lambs is thus possible, and the growth rate, carcass weight and carcass fatness of immunocastrates are similar to that of elastrator-castrated lambs.