Scielo RSS <![CDATA[South African Journal of Animal Science]]> vol. 42 num. 5 lang. es <![CDATA[SciELO Logo]]> <![CDATA[<b>Improved production efficiency in cattle to reduce their carbon footprint for beef production</b>]]> The FAO publication, Livestock's Long Shadow, indicated that livestock is responsible for 18% of the world's greenhouse gas production thereby creating the perception that livestock is a major cause of global warming. Methane (CEL) makes up 16% of total world gas emissions and is the second most important greenhouse gas (GHG) after carbon dioxide (CO2). Ruminants are important to mankind since most of the world's vegetation biomass is rich in fibre and only ruminants can convert this vegetation into high quality protein sources for human consumption. In spite of this important role of livestock, it is singled out as producing large quantities of GHG that contribute to climate change, since enteric fermentation is responsible for 28% of global CH4 emissions. However, the net effect from livestock is only a 4.5% contribution to GHG. The livestock industry should be aware of the effect of livestock on climate change and therefore it is important that mechanisms are put in place to mitigate this effect. The improvement of production efficiency through increased production per constant unit, crossbreeding and genetic improvement may be a cost effective and permanent way of reducing the carbon footprint of beef cattle. <![CDATA[<b>Selenium concentration of maize grain in South Africa and possible factors influencing the concentration</b>]]> A total of 896 maize grain samples were obtained from all the maize silos throughout South Africa (231 silos) and analysed for selenium (Se) content. This information was used to compile a regional distribution map of the Se content of maize grain in South Africa. Of the samples analysed, 94% contained below 50 µg selenium/kg DM and can thus be classified as deficient from an animal and human nutritional point of view. Maize grain in South Africa is therefore a poor source of Se for animals and humans. The geographical distribution of Se values of maize grain is consistent with that of previous studies on the Se status of herbivores in South Africa, suggesting that plants growing in most of the maize-producing areas of the country contain low concentrations of Se. However, these findings contradict those of the soil Se status in the country as reported by the Agricultural Research Council's Institute for Soil, Water and Climate, which states that the eastern part of the maize-producing areas of the country tends to have adequate to high soil Se levels and the western areas to have low levels. These contradictory results can be explained to a large extent by the varying soil pH throughout the country. Soil pH plays a primary role in the availability of selenium to plants. Although the eastern parts of the country tend to have high Se concentration in the soil, it is not available to the maize plant owing to a low soil pH, while in the western parts of the country, where soil pH may be suitable for Se uptake by plants, there seems to be an inadequate concentration of available Se in the soil. <![CDATA[<b>Environmental factors influencing milk urea nitrogen in South African Holstein cattle</b>]]> By knowing the milk urea nitrogen (MUN) content of dairy cows, the efficiency of dietary nitrogen utilization can be improved. The main objectives of this study were to identify and quantify environmental factors affecting MUN in South African Holstein cows. This will enable better interpretation of MUN results by accounting for such factors. A total of 82 900 test-day records of 9 901 Holstein cows from 40 herds participating in the South African National Milk Recording and Improvement Scheme (NMRIS) during the period 2007 to 2010 were used. An analysis of variance was performed to determine environmental factors significantly affecting MUN. Significant factors were herd-test-day, year of calving, parity, number of times milked per day and lactation stage. Herd-test-day had the largest effect, accounting for 48.3% of the total variation. Trends in least squares (LS) means for MUN over lactation stages were similar for all parities; however, means were slightly lower in parity 3 than the first two parities. The LS mean for 2008 was the lowest (13.9 mg/dL) in comparison to other years. Cows milked twice daily had a higher MUN LS mean (15.5 mg/dL) in comparison to those milked three times per day (13.4 mg/dL). Results of this study provided the basis for proper use and better interpretation of MUN data. <![CDATA[<b>The effects of an active live yeast product on the growth performance of finishing lambs</b>]]> A study was conducted to evaluate the effects of a rumen-specific, active live yeast (Saccharomyces cerevisiae; SC CNCM I-1077), alone or in combination with an ionophore (lasalocid-Na) in standard feedlot diets, on production performance and carcass quality of lambs. Sixty South African (S.A.) Mutton Merino lambs, weighing 25.7 ± 2.2 kg, were randomly allocated to four treatments (15 lambs per treatment) and further subdivided into five replicates per treatment (three lambs per replicate). The four dietary treatments consisted of an iso-nitrogenous and iso-energetic basal diet (177 g crude protein (CP)/kg dry matter (DM) and 276 g neutral detergent fibre (NDF)/kg DM) differing only in the additive included, i.e. (i) the control (C) diet (no additive), (ii) live yeast (SC) (220 g/ton), (iii) ionophore (G) (120 g/ton) and (iv) both live yeast with ionophore (SCG) at the same mentioned levels. After adaptation (8 days), the experimental diets were fed for 47 days in a finishing period. Feed intake and body weights were recorded weekly. At completion all animals were slaughtered (44.5 ± 3.8 kg) and the cold (2 °C) carcass weight and carcass characteristics recorded. Dietary treatment had no effect on feed intake, daily live weight gain, feed conversion ratio, carcass weight and carcass characteristics. Carcasses were leaner on the ionophore treatment (G) in comparison to the control diet (C). The results suggested that this rumen-specific live yeast included alone or in combination with an ionophore in finishing diets, containing less than 28% NDF/kg DM, did not affect performance and carcass traits of S.A. Mutton Merino lambs. <![CDATA[<b>Estimation of genetic parameters for growth traits in Brangus cattle</b>]]> A combination of multiple trait and repeatability models were used to estimate genetic parameters for birth weight (BW), weaning weight (WW), yearling weight (YW), eighteen month weight (FW) and three measurements of mature weight (MW) using 23 768 records obtained from the South African Brangus Cattle Breed Society. The data covered a period of 7 generations from 1985 to 2010. Direct heritability estimates obtained were 0.21 ± 0.024, 0.23 ± 0.021, 0.22 ± 0.025, 0.29 ± 0.029 and 0.24 ± 0.019 for BW, WW, YW, FW and MW, respectively. Maternal heritability estimates for birth weight and weaning weight were 0.05 ± 0.01 and 0.11 ± 0.001, respectively. The direct genetic correlations between the different traits were all positive, ranging from moderate (0.43 ± 0.081) between YW and MW to high (0.99 ± 0.043) between WW and FW. <![CDATA[<b>Genetic evaluation of growth traits in beef cattle using random regression models</b>]]> Direct- and maternal heritabilities were estimated for weight traits in Brangus cattle using random regression models. After editing, 54 924 records, from birth- (BW) to mature weight (MW) from 21 673 animals were selected for analysis. The data, which covered a period of 8 generations (1985 to 2010), were transformed to a log scale to accommodate the wide range of weights being studied (15 to 850 kg). Traits included in the analysis were birth- (BW), weaning- (WW), yearling- (YW), eighteen month- (FW) and three measurements of mature weight (MW). Linear polynomials with intercepts were fitted using random regression models. The direct heritability estimates were moderate and ranged from 0.13 to 0.25 while maternal heritability estimates were low ranging from 0.05 to 0.06. <![CDATA[<b>The <i>in vitro</i> fermentation of maize stover as affected by faecal bacteria obtained from ungulates</b>]]> The effect of different inoculum sources, obtained from the faeces of ungulates, i.e. horses (H), wildebeest (WB) and zebra (ZB) and combinations of inoculum sources on the fermentation of maize stover (MS) was investigated. Combined sources (CS) were: (1) H+WB, (2) H+ZB, (3) WB+ZB and (4) H+WB+ZB. Fresh faecal inocula were cultured in the laboratory on MS and lucerne (mixed in 1 : 1 ratio) with salivary buffer for 72 h at 38 °C prior to application as an inoculum or extraction of crude protein (CPZ) for enzyme assays. Crude protein was precipitated using 60% ammonium sulphate and analyzed for exocellulase, endocellulase and hemicellulase specific activities (jig reducing sugar/mg CPZ). An in vitro fermentation study was done by transferring 33 mL of laboratory cultured faecal inoculum into 67 mL of salivary buffer containing 1 g MS and incubating for 72 h at 38 °C. Exocellulase specific activities differed among the seven inoculum sources. Exocellulase activity ranked the different microbial sources according to their fibrolytic potential as follows: 1 > 2 > 4 > H > ZB > WB >3. Total gas, true degradability (TD), microbial yield and total short chain fatty acids (SCFA) were higher in the CS than in the individual systems. Systems 1 and 3 had the highest TD (714mg/g CPZ) and total SCFA (680 mg/g CPZ), respectively. True degradability, total gas, total SCFA, partitioning factor and degradability efficiency ranked the microbial ecosystems according to their fibrolytic potential as follows: 3 > 1 > 4 > WB > 2 > ZB >H. Inoculum sources differed in fibrolytic digestion, with microbes from CS (1) and (4) proving to be the best. Further investigation is essential towards using inoculums sources as possible feed additives in ruminants. <![CDATA[<b>Fatty acid composition and oxidative stability of lambs' meat as affected by a bioflavonoid antioxidant and fat sources</b>]]> A study was conducted to investigate the effects of a synthetic or natural antioxidant and fat saturation, in a standard feedlot diet, on fatty acid composition and oxidative stability of lamb. The four dietary treatments consisted of the same basal diet providing 187 g crude protein (CP), 355 g neutral detergent fibre (NDF), and 71 g ether extract (EE) per kg dry matter (DM), differing in fat source (30 g/kg of either saturated beef tallow or unsaturated soybean oil) and type of antioxidant included (125 g/t of either a synthetic or natural antioxidant). Eighty four S.A. Mutton Merino lambs weighing 27.6 ± 1.7 kg were divided into four groups and randomly allocated to four dietary treatments (n = 21 lambs/treatment) subdivided into 7 replicates/treatment (n = 3 lambs/replicate). After an adaptation period of 8 days, all lambs received complete diets for a further feeding period of 41 days. At termination of the study, seven lambs per treatment, weighing 45.1 ± 3.0 kg, were randomly selected and slaughtered. Loin chops from each carcass were used for fatty acid, colour (a* values) and thiobarbituric acid reactive substance (TBARS) analysis. Meat colour was determined on days 0 and 7 after being stored at 4 °C under fluorescent light. The malonaldehyde content per kg meat was determined on days 0, 7 and 90 after being stored at -18 °C in the dark. It was found that dietary treatment had no effect on colour stability as depicted in a values. The malonaldehyde content per kg meat was higher on days 0 and 90 for the unsaturated soybean oil treatment. Beef tallow inclusion resulted in an increase in palmitoleic acid, where soybean oil inclusion resulted in an increase in linoleic and α-linolenic acids in both lean and subcutaneous fat tissue. Natural antioxidant inclusion in the diet only increased the palmitoleic acid content of subcutaneous fat. The results suggested that the fatty acid profile of lamb meat can be favourably manipulated by the source of fat included in the diet. <![CDATA[<b>Digestion and microbial protein synthesis in sheep as affected by exogenous fibrolytic enzymes</b>]]> The aim of the study was to determine the effect of an exogenous fibrolytic enzyme (EFE) on the ruminal disappearance of dry matter (DM), neutral detergent fibre (NDF), crude protein (CP) and on the microbial protein synthesis (MPS) in sheep of a milled substrate consisting of a 50 : 50 mixture of lucerne hay (LH) and wheat straw (WS). Four cannulated Döhne-Merino sheep were randomly assigned to two groups in a 2 x 2 cross-over experiment. Additional to the in situ study, the effects of an exogenous fibrolytic enzyme (EFE) on the in vitro gas production (GP) and ANKOM digestion systems on the mixture of milled LH and WS were determined. The substrate was pre-treated with distilled water (control) or EFE (treatment) 12 hours prior to incubation to allow interaction between the substrate and enzyme. Adding EFE significantly improved the in vitro cumulative gas production (GP), but it did not affect the in vitro MPS measured as purine derivates of the GP residues. The enzyme significantly increased the in vitro DM and NDF disappearances after 36 hours. However, the in situ disappearances of DM, NDF and CP of the roughage mixture were not affected by the EFE. Further, the in situ MPS was increased significantly with the EFE treatment of the mixed substrate. It is concluded that the improved ruminal digestion of DM, NDF and CP is not only due to direct enzyme hydrolysis, but also due to the improvement of MPS. <![CDATA[<b>Evaluation of silver nanoparticles as a possible coccidiostat in broiler production</b>]]> The effect of administering low (15 mg/L) levels of silver nanoparticles in the drinking water of broilers (n = 40) was investigated as a potential replacement for antibiotic coccidiostats (Salinomycin® or Baycox®) in two trials. Four treatments were used: (1) challenged (with 3.3 x 10(5) Eimeria tenella oocysts via oral gavage in the first trial and 1.6 x 10(4) in the second trial) and medicated with silver nanoparticles in drinking water; (2) challenged and medicated with a registered ionophore coccidiostat (Salinomycin® in Trial 1 and Baycox® in Trial 2); (3) challenged and unmedicated and (4) unchallenged and unmedicated (control). Caecal lesions were scored on a scale from 0 - 4, while liver, caecal and kidney samples were taken to determine silver content. Growth performance was subjected to ANOVA using Statistica®. In Trial 1, neither the challenge (587 g vs. 561 g) nor the use of silver nanoparticles (587 vs. 555 g) had a significant effect on the weight gain of chicks from 13 to 27 days of age. The coccidiostat treatment group had a significantly lower weight gain than the unmedicated control (219 vs. 560.5 g) but had the lowest lesion score of 2.3. The silver nanoparticles group had, numerically, a slightly better score than the untreated group. The unchallenged control group had scores of 0. In the second trial there were no significant differences in growth performance between the treatments and there were no lesions, but both the silver nanoparticles group and the coccidiostat group had 50% less oocysts in the faecal samples compared to the control group. The silver content of the livers of the silver nanoparticle group was 0.083 mg/kg compared to 0.001 mg/kg in the control group. The results of this study on the use of silver nanoparticles as a coccidiostat were therefore not conclusive, but holds promise so that further investigation is warranted. <![CDATA[<b>Relationship between pelvic and linear body measurements in Dorper ewes</b>]]> Low lifetime rearing success and high perinatal mortality of lambs have been associated with small pelvic areas in ewes. It would therefore make sense to include pelvic area as a criterium for selecting breeding ewes; however, measuring it in vivo poses some challenges. The aim of this study was to determine pelvic height, width and area and to estimate correlations between these measurements and other external linear body parameters, i.e. body height, shoulder height, chest depth, front quarter width, hindquarter width, rump length and rump slope in Dorper ewes. A total of 332 young Dorper ewes (± 12 months old; 48.0 ± 5.9 kg) were used. The overall mean pelvic area of yearling Dorper ewes was 35.4 ± 4.9 cm². Registered ewes recorded significantly larger pelvic areas (37.4 ± 4.3 cm²) than commercial ewes (33.9 ± 3.8 cm²). Results also indicate no correlations between pelvic measurements and other body measurements considered in this study, indicating the need to measure the pelvic area of ewes directly. The pelvic meter and techniques used in this study proved to be relatively easy to use in measuring the pelvises of sheep. <![CDATA[<b>Effect of dietary fat source on fatty acid profile and lipid oxidation of eggs</b>]]> This study investigated the effects of supplementary dietary lipid sources on the fatty acid profile and lipid oxidation of eggs. Five isoenergetic (12.6 MJ AME/kg DM) and isonitrogenous (170 g CP/kg DM) diets were formulated, using a control diet (50 : 50 blend of fish- and linseed oil), fish oil, sunflower oil, high oleic acid (HO) sunflower oil and tallow at a 30 g/kg inclusion level. Two hundred individually caged HyLine Silver-Brown hens (20 weeks of age) were randomly allocated to the five dietary treatments (n = 40 hens/treatment). Birds received the experimental diets from 20 weeks of age. At 30 weeks of age, 12 eggs per treatment were randomly selected for analyses of egg yolk fatty acid methyl esters (FAME), thiobarbituric acid reactive substances (TBARS) and peroxide values (PV). Dietary lipid sources affected FAME, TBARS and PV of egg yolk significantly. The fish oil treatment resulted in the highest TBARS (0.27 mg malonaldehyde/kg yolk) and PV (3.96 milli-equivalent peroxide/kg fat) whereas the HO sunflower oil resulted in the lowest TBARS (0.13 mg malonaldehyde/kg yolk) and PV (2.77 milli-equivalent peroxide/kg fat). Fish oil also resulted in the lowest n-6 to n-3 ratio (1.16 to 1), while sunflower oil resulted in the highest ratio (24.6 to 1). Results indicate that the fatty acid profile of eggs could be altered by means of dietary intervention. However, an improvement of omega-3 type fatty acids of eggs will result in a higher susceptibility to lipid oxidation and possibly a shorter shelf-life of stored eggs. <![CDATA[<b>Some insights into the phenotypic and genetic diversity of indigenous pigs in southern Africa</b>]]> Indigenous pigs in southern Africa are mainly owned by economically vulnerable groups in marginal areas where they are used as a source food, income and security. A study was carried out to achieve three objectives: to describe pig production systems, get a phenotypic description of the pigs and to characterize them genetically. A survey of 199 farmers in three districts in South Africa, (Vhembe, OR Tambo and Alfred Nzo) and one district in Zimbabwe (Chirumhnazu) was carried out. Additional farmers in Malawi (Dedza, Mchinji and Salima) and Zimbabwe (Mutoko) were sampled in order to meet the other two objectives. Most of the pigs (69.7%) were owned by women, with men owning 20.5% and children the remainder. Production of the pigs was constrained by several factors including disease, inadequate feeds, poor housing and lack of knowledge. The majority of the pigs were small and black with characteristics that are probably suited for thermoregulation in arid environments. The third objective was achieved through genotyping 111 pigs using 22 microsatellites. Preliminary results indicate very little differences across populations with an overall inbreeding coefficient of the subpopulation relative to the total population (F ST) of 0.071. The results indicate that the indigenous pigs in southern Africa are relatively homogenous. <![CDATA[<b>Preliminary report</b>: <b>Pedigree analysis of the Brangus cattle in South Africa</b>]]> The aim of the study was to investigate some population parameters, including generation interval, inbreeding and effective population size of Brangus cattle in South Africa (SA) to assist in constructing an effective selection programme for the SA Brangus breed. Pedigree analysis can describe the genetic variability and change over time, making it an important tool to be used to assess parameters like generation interval, inbreeding, effective population size and number of animals selected against number born. These traits can be used to make more informed selection decisions in order to maintain a genetically healthy population through a better understanding of the dynamics within the population. A Population Structure- and Pedigree Analysis Report was generated with the PopReport programme from the Institute of Farm Animal Genetics (FLI) with a Brangus datafile containing 65 536 animals. Results were reported for the time period of 1986 to 2008 and the following results were obtained: 3-generation pedigree completeness is at 73.8% for 2008, with an inbreeding coefficient of 1.39% and an annual increase in inbreeding of 0.058%. Weighted generation interval was 5.17 years and the effective population size based on the average inbreeding was 166.7 animals. <![CDATA[<b>Effect of dietary lipid saturation on the production performance of layers</b>]]> This study investigated the effects of dietary lipid saturation on production parameters of laying hens during the peak-of-lay period. Five isoenergetic (12.6 MJ AME/kg DM) and isonitrogenous (170 g CP/kg DM) diets were formulated, using a control diet (50 : 50 blend of fish- and linseed oil), fish oil (poly-unsaturated n-3), sunflower oil (poly-unsaturated n-6), high oleic acid sunflower oil (mono-unsaturated n-9 ) and tallow (saturated) at a 30 g/kg inclusion level. Two hundred individually caged HyLine Silver-Brown hens (20 weeks of age) were randomly allocated to the five dietary treatments (n = 40 replicates/treatment). Hens received their respective experimental diets until 40 weeks of age. During weeks 24, 28, 32, 36 and 40 all eggs produced, were recorded, individually weighed and the daily feed intake of birds determined. Data for the respective collection weeks were pooled for calculation of production parameters during peak-of-lay. Dietary lipid saturation level had no effect on daily feed intake of hens, hen-day egg production, egg output and live weight of hens during the peak-of-lay period. The mono-unsaturated n-9 diet (high oleic acid sunflower oil) had the lowest feed efficiency (0.47), while that of the control-, polyunsaturated n-6 (sunflower oil) and the saturated (tallow) treatments were the highest (0.49). Results of the current study suggest that although dietary lipid saturation level had no effect on most of the production performances, it might influence the efficiency of feed utilization. <![CDATA[<b>Preliminary results on the effect of the inclusion of cottonseed oilcake meal on the feed intake and growth of slaughter ostriches <i>(Struthio camelus</i> var. <i>domesticus)</i></b>]]> The ostrich (Struthio camelus var. domesticus) is an important animal in the livestock industry in South Africa. Ostrich production is an intensive production system and feed cost contributes approximately 75% of the total cost of production. The objective of this study was to determine the effect of the replacement of soybean oilcake meal (SOCM) with cottonseed oilcake meal (CSOCM) on the production performance of slaughter ostriches. A total of 105 birds of both sexes were divided into five groups of 21 birds each. All birds were fed five iso-nutritional diets in which SOCM was gradually replaced by CSOCM (0% up to 12% of the total diet). Ostriches in each treatment were subdivided into three replicate pens containing seven birds each. Body weights of birds were recorded at the start of the experiment and thereafter on a monthly basis throughout the study. Inclusion level of CSOCM had no effect on the feed intake and feed conversion rate of slaughter ostriches. Birds consuming the diet with 0% CSOCM had a significantly lower growth rate than the birds consuming the diets containing respectively 9% and 12% CSOCM. In a complementary palatability study, no significant differences in feed intake were observed between the diets with and without CSOCM. <![CDATA[<b>Effect of slaughter technique on bleed-out, blood in the trachea and blood splash in the lungs of cattle</b>]]> The South African Animal Protection Law, which requires animals to be stunned before slaughter, allows certain exemptions to accommodate religious slaughter. The supporters of the Jewish method of slaughter (Shechita), in which animals are slaughtered without pre-stunning, claim that the bleed-out and some quality parameters are better than when the animals are stunned before slaughtering. In this study, the percentage blood loss (BL%), presence (%) of blood in the trachea (BLT%) and blood splash % in the lungs (BS%), between the Shechita (Kosher) group and the conventionally slaughtered group of cattle were compared. Results showed no significant difference between the two treatment groups in terms of blood loss, although the conventional group had a higher bleed-out. However, there were significant differences in the presence of blood in the trachea and blood splash in the lungs, with the Kosher group having the highest percentages of these quality defects. Out of 170 animals examined for Kosher, 93% had blood lining the trachea, ranging from one to over 50%. From the 141 animals examined for the conventionally-slaughtered group, 97% had no blood lining the trachea while the remaining 3% had less than 10% blood lining the trachea. Furthermore, 65% of animals slaughtered in the Kosher way had blood splash ranging from 5% to over 50%, while the conventional group had only 0.7% incidence of blood splash in the lungs. These results show that slaughtering animals without stunning do not improve bleed-out, but increase blood in the trachea and blood splash in the lungs. <![CDATA[<b>Comparison of different extenders and storage temperature on the sperm motility characteristics of Kolbroek pig semen</b>]]> Maintaining a successful pig artificial insemination programme depends on a number of factors, including evaluation of semen characteristics. This study compared the efficacy of different extenders on the sperm motility of Kolbroek semen during short term storage at 4 °C and 25 °C. Semen was collected from Kolbroek boars using the gloved hand technique and transported to the laboratory for evaluation. Semen was pooled and randomly allocated to four groups and diluted at a ratio of 1:1 (v/v) with Beltsville thawing solution (BTS), Kobidil+, egg yolk citrate (EYC) and non-extended semen (Control). Each extender had two similar semen samples, making a total of eight samples. Extended and non-extended semen were stored at 4 °C and the other samples at 25 °C for 1 h. Data were analyzed using analysis of variance (ANOVA). The total sperm motility of semen stored at 25 °C was higher when semen was extended with BTS and Kobidil+ in comparison to the egg yolk citrate diluent. However, total sperm motility in the non-extended semen did not differ from the BTS and EYC group during storage at 25 °C. Sperm progressive motility was higher in the BTS group, compared to the Kobidil+ and non-extended groups. Sperm motility of Kolbroek semen at 4 °C did not differ between all extender treatments. Total motility rate was significantly higher when Kolbroek sperm were stored at 25 °C than at 4 °C. It can be concluded that Kolbroek sperm, extended with BTS, maintained their motility rate better for short term storage at 25 °C in comparison to 4 °C. <![CDATA[<b>Production response of lambs receiving creep feed while grazing two different pastures</b>]]> The aim of the study was to determine the production responses of lambs receiving either creep feed or not while grazing two different pastures. The production of ewes within each treatment was also recorded. The study was conducted at both the Kromme Rhee and Langgewens Research Farms. At Kromme Rhee, sheep grazed kikuyu (Pennisetum clandestinum) pasture under irrigation. Dohne Merino (n = 47) ewes, with their lambs, were randomly allocated to four groups. At Langgewens, the sheep grazed medic (Medicago parrabinga) pastures under dry-land conditions. South African Mutton Merino ewes (n = 89), with their lambs, were randomly divided into four groups. At Langgewens creep feed was provided at 200 g/lamb/day from the start of the study. This was increased by 100 g/lamb/day every week up to a maximum of 600 g/lamb/day. At Kromme Rhee, creep feed was provided at 200 and 300 g/lamb/day for the first and second week, respectively. From week three creep feed was provided ad libitum. At both locations ewes and lambs were weighed once a week. Live weight data of lambs and ewes were analysed by means of a multifactor analysis of variance with treatment (creep feed or no creep feed) and birth status (single and twins) as main factors. Provision a creep feed at Langgewens significantly increased lamb weight, but had no effect on ewe live weight. The provision of creep feed At Kromme Rhee significantly increased lamb weight as well as ewe weight. At both locations, birth status had no effect on the production parameters for ewes or lambs. <![CDATA[<b>The effect of dietary garlic powder and a low temperature on the physical quality of stored eggs</b>]]> Eggs are a rich source of protein having, a primary advantage in satisfying human nutritional needs. However, the loss in egg quality within a short time during storage calls for more research to improve their condition following storage. This study investigated the potential of garlic powder as a feed supplement and low temperature in maintaining physical egg quality during storage. Seventy two thirty-week old hens of the Dekalb white strain were used in the study. Hens were divided into three dietary treatment groups in a completely randomized design experiment. Three treatments were control (no garlic addition), 3%, and 5% garlic powder (GP) additions to a basal diet on a weight ratio basis. Birds were fed the experimental diets for seven weeks. Eggs (n = 108) were collected from days 43 to 45 of the trial and stored either at 8 ± 2 °C or 25 ± 2 °C for 21 days. Feeding GP in the hens' diet improved Haugh unit value by 11.9 HU and albumen height by 1.4 mm when eggs were stored at 25 ± 2 °C. For eggs stored at a low temperature, GP supplementation had no affect on egg quality indicators. In comparison to values for fresh eggs, egg weight and albumen percentage were significantly reduced. An increase in yolk percentage was recorded in eggs stored at 25 ± 2 °C. Similarly, changes were marginal for eggs stored at a low temperature. This study indicated that both dietary garlic powder and low temperature significantly maintained albumen quality of eggs stored during summer. <![CDATA[<b>Urinary catecholamine concentrations in three beef breeds at slaughter</b>]]> Animal welfare has become an important determinant of meat quality with poor animal temperament leading to huge economic losses to the meat industry due to carcass bruising and condemnation. Handling and transport of live animals is a stressful experience for animals. The temperaments of cattle affect their behaviour and differ between breeds, i.e. studies have shown that Bos indicus types are more temperamental than Sanga and Bos taurus types. Catecholamines (CAT's) are considered as indicators of stress, because higher concentrations of CAT's in brain tissue were noted in animals that are better adapted to stressful situations. In the present study, urinary CAT's of three beef breeds were determined immediately post mortem. Brahman cattle represented Bos indicus types, Simmentaler cattle represented Bos taurus types and Nguni cattle represented the Sanga type. Nguni steers showed higher urinary norepinephrine (NE) and epinephrine (E) concentrations than Brahman and Simmentaler steers. Simmentaler steers showed a higher concentration of urinary dopamine (DA) than Br and Ng. The results suggest that Nguni cattle are less stress sensitive compared to the other beef breeds studied. These observations may be due to the process of domestication and selection for specific genes that influence tameability and consequently resulting in a shift in circulating concentrations of urinary CAT's. <![CDATA[<b>The use of near infrared spectroscopy (NIRS) to predict the chemical composition of feed samples used in ostrich total mixed rations</b>]]> The wet chemical analysis of feed samples is time consuming and expensive. Near infrared spectroscopy (NIRS) was developed as a rapid technique to predict the chemical composition of feeds. The prediction of accuracy of NIRS relies heavily on obtaining a calibration set which represents the variation in the main population, accurate laboratory analyses and the application of the best mathematical procedures. In this study NIRS was used to determine the chemical composition of total mixed rations (TMRs) used in ostrich diets. A sample population of 479 ostrich feed samples was used in the calibration and 94 samples were used in the independent validation of dry matter (DM), ash, crude protein (CP), ether extract (EE), crude fibre (CF), acid detergent fibre (ADF), neutral detergent fibre (NDF), gross energy (GE), calcium (Ca) and phosphorus (P). Coefficient of determination in validation (r²v) and standard error of prediction (SEP) was satisfactory (r²v values higher than 0.80). Coefficient of determination and SEP values for CP, EE, CF, ADF, NDF and GE were 0.97% and 0.74%, 0.89% and 0.50%, 0.94% and 1.41%, 0.89% and 2.67%, 0.95% and 2.81% and 0.80% and 0.28 MJ/kg, respectively. Less accurate values (r²v below 0.80) were obtained for DM, ash, Ca and P being 0.57% and 0.28%, 0.67% and 1.29%, 0.43% and 0.59% and 0.49% and 0.11%, respectively. The study indicated that NIRS is a suitable tool for a rapid, non-destructive and reliable prediction of the chemical composition of ostrich TMRs. <![CDATA[<b>A description of body growth and composition of South African Black ostriches (<i>Struthio camelus</i> var. <i>domesticus</i>) under free-choice feeding conditions</b>]]> This study describes changes occurring in the live weight and body composition of male and female South African Black ostriches over a growing period of 285 days. Forty-five birds were given four diets with different protein (ca. 180 and ca. 120 g/kg feed) and energy (ca. 8.5 and ca. 13.5 MJ ME/kg feed) levels on a free choice basis, assuming that the birds would select feeds according to their protein and energy requirements and subsequently growing close to their genetic potential. Birds were weighed at approximately 10-day intervals and randomly selected birds (n = 9) were slaughtered at 1, 54, 120, 162 and 285 days of age respectively. Proximate chemical analyses were done on the complete empty carcasses and the components were expressed as a percentage of live weight at the different slaughter ages. An adapted form of the Gompertz growth curve (Wt = Wm*(exp(-exp(-B*(t-t)))) (where Wt is body weight (kg) at time t (d), Wm is the mature weight (kg), B the rate of maturing (/d) and t* the age (d) at which growth rate is maximised), was fitted to the live weight data and the weights of each chemical component (calculated from percentage of total body weight). The growth parameters Wm, B and t* were calculated for each chemical component. The growth parameters Wm, B and t were estimated as 119 kg, 0.009/d and 156 d respectively. Gompertz parameters estimated for the different chemical components were: BWam = 55.0, B = 0.014 and t = 117 for moisture, BPm = 44.5, B = 0.015 and t* = 114 for protein, BLip m = 33.6, B = 0.013 and t* = 143 for lipid, and Bash m = 10.3, B = 0.016 and t = 118 for ash. If it is assumed that ostriches in this study selected feed according to their protein and energy needs on each day of the growing period resulting in their growing close to their genetic potential, the results presented here would represent the potential growth rate of South African Black ostriches. Each chemical component was described by a Gompertz growth curve, and the rate of growth parameters illustrated that the tissues are allometrically related. <![CDATA[<b>The effect of vitamin E supplementation on the libido and reproductive capacity of Large White boars</b>]]> In this study the effect of dietary supplementation of vitamin E on libido, servicing capacity (SC), sperm quality and serum α-tocopherol of Large White boars was evaluated. Twenty four boars were divided into three groups of eight boars each. Groups were randomly allocated to treatment groups, i.e. 0, 40 or 70 IU of dl-α-tocopheryl acetate/kg of diet. Libido was defined as the time from intromission to ejaculation being recorded as the reaction time (RT) in minutes. Serving capacity (SC) was measured by number of mounts, combats, head-kicks, anogenital sniffs during a 30 min test period. Semen was collected by the use of an artificial vagina following the SC test, and afterwards analyzed for quantitative and qualitative parameters. The 70 IU supplementation of dietary vitamin E per kg diet to pigs resulted in the highest number of mounts, combats, head-kicks and anogenital sniffs with the shortest RT in comparison to the 40 and 0 IU vitamin E supplementation. The 70 IU vitamin E boar group produced semen with the highest semen volume, sperm cell motility, progressive movement, acrosomal normal apical ridge (NAR), percentage live sperm, sperm concentration per mL semen volume and total number of sperm per ejaculate and improved serum α-tocopherol concentrations (5.1 ± 0.5 µg/mL). Results suggest that supplementing 70 IU per kg α-tocopheryl acetate in boar diets appears to be most beneficial in optimizing libido and reproductive capacity in breeding boars.