Scielo RSS <![CDATA[South African Journal of Animal Science]]> vol. 49 num. 4 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>Investigating novelty traits to improve cow-calf efficiency in South African Afrikaner, Angus and Charolais for climate-smart production</b>]]> The aim is of the study was to identify novelty traits that could be used as breeding objectives to improve cow-calf efficiency and describe cow efficiency in extensive systems in support of climate-smart production in beef cattle. The traits that were investigated were 'weaning weight of the calf as a trait of the dam' (K205) and 'kilogram calf weaned per large stock unit' (KgC/LSU. The latter trait is a value that expresses performance (calf weaning weight) per constant unit, namely per LSU. This may be a useful breeding objective or goal to increase production efficiency, which may reduce the carbon footprint of extensive beef cow-calf production systems. The investigation of the novel traits was conducted on three diverse breeds, namely Afrikaner, Angus and Charolais, with 6104, 7581 and 2291 complete cow-calf records, respectively. Only cows with all three first parities recorded were used to investigate KgC/LSU and K205, as breeding objectives to improve cow-calf efficiency. The heritabilities for KgC/LSU were 0.52, 0.24 and 0.21 for the Afrikaner, Angus and Charolais, respectively, and for K205 were 0.40, 0.17 and 0.13 respectively. The genetic relationship between KgC/LSU and K205 for Angus and Charolais varied substantially. In Charolais cows a strong negative correlation (-0.75) was found, while a strong positive correlation (+0.84) was estimated in Angus cows. These results indicate that a 'cow efficiency index' in which several traits (production, fertility and efficiency) are included may be a more effective alternative breeding strategy. Breeding strategies and production systems to improve the production efficiency of beef cattle could play a significant role in reducing the carbon footprint and would enhance climate-smart beef production. <![CDATA[<b>Effects of exogenous fibrolytic enzymes on the ruminal fermentation of agro-industrial by-products</b>]]> This research was performed to evaluate the effects of increasing doses of exogenous fibrolytic enzymes (EFE), namely at 0 (control), 1 (low), 2 (medium) and 4 (high) μΙ,/g dry matter (DM), on the ruminal fermentation of low-quality agro-industrial by-products, grape pomace, almond hull and pomegranate peel. For pomegranate peel, the addition of EFE increased gas production linearly from the immediately soluble fraction, and from the insoluble fraction, the potential of gas production (significant linear effect), organic matter digestibility and metabolizable energy. The highest doses were the most effective. As the doses increased, the effectiveness increased accordingly. Unlike pomegranate peel, EFE had a quadratic effect on the indices of almond hull, namely a significant response on gas production from the immediately soluble fraction, the insoluble fraction, potential of gas production, organic matter digestibility and metabolizable energy. The lowest dose was the most effective while the highest dose had inhibitory effects for gas indices, organic matter digestibility and metabolizable energy. On the other hand, this supplementation had no effect on the ruminal fermentation of grape pomace. This study indicates that the response to this feed additive was influenced by the dose, the structure of the substrate, and the interaction between dose and the substrate. Exogenous fibrolytic enzymes could enhance the use of almond hull and pomegranate peel in ruminant nutrition, and reduce their negative environmental impact. <![CDATA[<b>Aluminosilicates and yeast-based mycotoxin binders: Their ameliorated effects on growth, immunity and serum chemistry in broilers fed aflatoxin and ochratoxin</b>]]> The aim of this study was to evaluate the effects of commercial toxin binders on growth performance, organ morphology, immunity and serum biochemistry in broilers. Dietary treatments consisted of the negative control (NC): experimental diet with aflatoxin B1 <20 parts per billion (ppb), ochratoxin A (OTA) <5 ppb; control (C) experimental diet without toxin binder; Z1: toxin binder 1 g/kg of zeta plus; Z2: toxin binder 2 g/kg of zeta plus; TX1: toxin binder 1 g/kg of Toxfin Dry; and TX2: toxin binder 2 g/kg of Toxfin Dry). Except for NC, all diets contained 57 ppb aflatoxin B1 and 23 ppb ochratoxin A. Feed intake was higher in the TX1, TX2, NC, Z2 and Z1 treatments than in the control. Weight gain was higher in Z2, TX2, Z1, TX1 and NC than in C. Feed conversion ratio (FCR) was poor in C. The control had the highest liver weight, though the weights of the spleen, kidneys and hearts of the birds were similar in all treatments. Gizzard weight, thymus weight, and bursa of Fabricius were lowest in C. The weight of the pancreas was similar among treatments. The antibody titres against new castle disease were higher in treatments Z2, Z1, TX2, TX1 and NC than in C. Urea and creatinine concentrations, and aspartate aminotransferase activity in serum were similar among treatments, whereas the serum alanine transaminase activity was higher in C than in Z1, TX1, TX2, Z2 and NC. It was concluded that growth rate, FCR and immunity indices were improved in broilers fed toxin binder. At lower levels of mycotoxin in feed, 1 g/kg of toxin binder (clay based or yeast based) was sufficient to ameliorate the adverse effects of aflatoxin B1 and OTA, whereas at higher levels of mycotoxins, supplementation of toxin binder should be increased. <![CDATA[<b>Genetic diversity and population structure of Turkish native cattle breeds</b>]]> Cattle are an important livestock species for human life, but certain breeds are at risk of extinction. Maintaining genetic diversity plays an important role in sustainable breeding and conservation programmes in farm animals. The aim of this study was to determine genetic diversity among five Turkish native cattle breeds. A total of 199 Turkish native cattle of the Native Southern Yellow (n = 40), South Anatolian Red (n = 40), Anatolian Grey Cattle (n = 40), Native Black Cattle (n = 39) and East Anatolian Red (n = 40) breeds were investigated using 22 autosomal microsatellite markers. The analysis revealed considerable genetic variation among these breeds. All loci were polymorphic, and a total of 545 alleles were found. Among these loci, only INRA032 was at Hardy-Weinberg equilibrium. Thirty-four private alleles with frequencies greater than 5% were found. Expected heterozygosity and polymorphic information content indexes were 0.87 and 0.88, respectively. Native Southern Yellow, South Anatolian Red and Native Black Cattle breeds were closely related. <![CDATA[<b>Antioxidant activity and duodenum transporter gene expression in quail fed citric acid</b>]]> The study aimed to evaluate the effects of citric acid supplementation on the performance and the gene expression in the duodenum of Japanese quail. Genes related to antioxidant activity: superoxide dismutase (SOD) and glutathione peroxidase 7 (GPX7); and genes related to nutrient uptake in the enterocytes' apical membrane: sodium-glucose cotransporter 1 (SGLT1, responsible for the glucose absorption), glucose transporter 2 (GLUT2) and B0AT1 (responsible for the absorption of neutral amino acids in brush board membrane) were evaluated. For this, 270 laying quails (Coturnix japonica) were fed a diet supplemented with 0%, 0.6% or 1.2% of citric acid. Gene expression was evaluated by the quantitative reverse transcription-polymerase chain reaction (qRT-PCR) at 35 days old (n = 5). The highest expression of the SGLT1 gene was observed in quails fed the 1.2% citric acid supplemented diet (0.120 AU). Birds fed diets with both levels of citric acid supplementation showed a higher B0AT1 gene expression than quails fed no citric acid. Quails fed the 1.2% of citric acid supplemented diet had the lowest SOD gene expression (0.3455 AU). The birds receiving the diets supplemented with citric acid showed a lower GPX7 gene expression than the quails fed the 0% citric acid diet. These results suggests that the effect of citric acid on gene expression in the digestive tract may have contributed to the greater weight gain and lower feed intake observed in birds fed diets supplemented with citric acid. <![CDATA[<b>Effect of additives on fermentation characteristics, nutrient values and <i>in vitro </i>fermentation profile of <i>Neolamarckia cadamba </i>leaf silage</b>]]> This study was designed to investigate the effects of additives on the ensiling characteristics of Neolamarckia cadamba leaf (NCL) silage. The NCL were allocated to six ensiling treatments, namely control (C-S), uncompacted (UC-S) (negative control), with the addition of sodium sulphite (S-S), with propionate (P-s), with citric acid plus sodium acetate (CA-S), and with glucose (G-S). Fermentation parameters, chemical compositions and in vitro fermentation profile of the silages were investigated after 60 days' storage. Compared with the control, the application of additives improved dry matter recovery (DMR), while UC-S had a poorer DMR. All the silages increased in pH value and acetate content, except for P-S. Lactate concentration was higher in S-S and G-S, and lower in UC-S, P-S, and CA-S. P-S, CA-S, and G-S had increased water soluble carbohydrate (WSC) concentrations. Soluble crude protein was higher in UC-S and CA-S. All the treated silage had greater gas production at slower rates, except for S-S. The fermentation of S-S, P-S and CA-S resulted in higher content of short-chain fatty acids and microbial crude protein relative to UC-S. S-S (38.82%) and CA-S (37.89%) had higher organic matter digestibility relative to the control (36.43%). S-S (42.80%) and P-S (43.99%) had higher crude protein digestibility, which was lower in UC-S (30.73%) when compared with the control (37.74%). There was no difference in the predicted available energy of these silages. The low ammonium nitrogen ratio and the high proportion of true protein inferred that protein was well preserved in these silages, even the uncompacted silage. These results suggest that sulphite and organic acids, such as propionate and citrate, could be an option to improve the feed quality of NCL silage, and its great protein conservation deserves more attention. <![CDATA[<b>Increasing reproductive rates of both sexes in dairy cattle breeding optimizes response to selection</b>]]> It was reasoned that technologies that increase the reproductive rate of males and females in dairy cattle would realize higher responses to selection. The authors tested this hypothesis using deterministic simulation of breeding schemes that resembled those of dairy cattle in Kenya. The response to selection was estimated for four breeding schemes and strategies. Two breeding schemes were simulated, based on artificial insemination (AI) and multiple ovulation and embryo transfer (MOET) reproductive technologies. The strategies were defined according to the use of conventional semen (CS) and X-chromosome-sorted semen (XS). The four strategies therefore were AI with CS (AI-CS) and XS (AI-XS), and MOET with CS (MOET-CS) and XS (MOET-XS). The four strategies were simulated based on the current dairy cattle breeding goal in Kenya. A two-tier closed nucleus breeding programme was considered, with 5% of the cows in the nucleus and 95% in the commercial. Dissemination of superior genetic materials in the nucleus was based on all four breeding strategies, while in the commercial only the AI-CS strategy was considered. The strategies that increased the reproductive rates of both males and females (MOET-CS and MOET-XS) realized 2.1, 1.4, and 1.3 times more annual genetic gain, return and profitability per cow, per year, respectively, than strategies that increased the reproductive rates only of males (AI-CS and AI-XS). The use of CS or XS, however, did not affect response to selection in the two schemes. The findings demonstrate that reproductive technologies such as MOET maximize response to selection in dairy cattle breeding. <![CDATA[<b>Reproductive and oxidative status of ewes supplemented with vitamin C during oestrous synchronization and early gestation</b>]]> The objective of the study was to evaluate the reproductive efficiency and antioxidant status of ewes supplemented with two levels of vitamin C during oestrous synchronization and early gestation. Sixty-three ewes were allocated to three treatments, namely T0: control group; T1: 3 g vitamin C coated with ethylcellulose (Rovimix C®, powder); and T2: 6 g vitamin C coated with ethylcellulose. The ewes received the dietary supplementation during an oestrus synchronization period and lasted until 18 days after breeding. The occurrences of oestrus, gestation, fecundity and prolificacy were measured. Blood samples were collected at various stages to determine antioxidant capacity and oxidative state, and progesterone, glucose and insulin concentrations. Percentage occurrence of oestrus and gestation was analysed using the Chi-Square test, prolificacy and fecundity by GENMOD, and blood tests by the PROC MIXED procedure. It was recorded that the concentration of vitamin C in plasma increased with the supplementation of 3 g and 6 g vitamin C. The antioxidant capacity was higher in T1 than in T0 and T2. Lipid oxidation, and glucose, insulin and progesterone concentrations were not affected. It is concluded that supplementation of 3 g vitamin C during oestrous synchronization and early gestation does not modify the reproductive responses of the ewes. However, the concentration of this vitamin in the blood increased and improved the antioxidant capacity of the animals. <![CDATA[<b>Productive performance, blood biochemical variables and immune responses of laying hens fed diets containing various fat sources</b>]]> This study was conducted to evaluate the effects of various fat sources on productive performance, blood biochemical variables and immune responses of laying hens. Laying hens were divided into seven groups, which received i) basal or control diet (no oil); ii) and iii) basal diets containing 1% and 3% soybean (SB) oil; iv) and v) basal diets containing 1% and 3% kilka oil (KO), and vi) and vii) basal diets containing 1% and 3% soybean fatty acids (SFA). Productive performance was evaluated from day 1 to day 84. Blood biochemical variables and immune responses were assessed on days 28, 56 and 84 of the trial. The study results indicated that the dietary inclusion of 1% and 3% KO and SFA and 3% SB oil could decrease the feed conversion ratio (FCR) and increase egg production and egg mass in comparison with the control group throughout the study. Immune responses of sheep red blood cells and antibody titre against hemagglutination inhibition (HI) were significantly higher in laying hens fed KO and SFA and 3% SB oil compared with the control group. The serum concentrations of low density lipoprotein-C (LDL-C), very low density lipoprotein-C (VLDL-C) and malondialdehyde (MDA) were not influenced by the inclusion of oil sources. The serum concentration of cholesterol was increased significantly in laying hens that were treated with oil on day 28. The inclusion of fat sources significantly increased the serum concentration of HDL-C. The use of KO and SFA could be recommended at lower levels to improve the performance, immunity and some blood variables in laying hens. <![CDATA[<b>Effect of varying levels of protein concentration on production traits of ostriches<i> (Struthio camelus </i>var. <i>domesticus)</i></b>]]> The ostrich industry is poised to recover from the recent lifting of the four-year export ban on fresh meat products to the European Union EU). However, during this period profit margins were severely affected and the need to minimize input costs was as important as it ever was, particularly nutrition. The aim of this study was to evaluate the influence of varying protein concentrations in the diets of slaughter ostriches on the production traits. Five treatment diets were formulated for each feeding phase (pre-starter, starter, grower and finisher), with a control diet, two diets that decreased in protein content and two diets that increased in protein concentration. There were three replications per treatment, resulting in 15 camps, which contained 20 chicks each. Differences were found in live weight of the birds at the end of each feeding phase, except for the finisher phase. Differences were found among the diets for dry matter intake (DMI), average daily gain (ADG), and feed conversion ratio (FCR). The control diet and the two diets that were formulated with higher protein concentrations had higher DMI values, better ADG, and more efficient FCR. Differences were found in cold carcass weights and thigh weights for the birds that were exposed to the treatment diets. The results indicated that the birds on the control diet and on the diets containing higher concentrations of protein, although not differing from each other, consistently outperformed the diets with lower concentrations of protein. From a financial standpoint it can be concluded that it does not make sense to increase the protein concentration in the diets beyond that currently used in the ostrich industry, while a decrease in protein concentration resulted in decreased production performance. <![CDATA[<b>PCR-RFLP-based identification of polymorphisms in <i>BMPR1B, GDF9 </i>and <i>BMP15 </i>genes associated with litter size in Beetal and Teddy goats</b>]]> The genes BMPR1B, GDF9 and BMP15 are oocyte-derived members of the transforming growth factor-β superfamily, which is essential for follicular growth and ovulation. The aim of the current study was to determine the incidence of reported mutations in exon 3 of BMPR1B gene, exon 1 of GDF9 gene, and exon 2 of BMP15 gene and their association with litter size in three parities of Beetal and Teddy goats. Based on the known mutations in these genes, PCR primers were designed to find out the polymorphism through the PCR-RFLP technique in 120 randomly selected animals of the two breeds, which vary in their prolificacy. The current results show that there were significant differences in litter size [1.708 ± 0.060 in Beetal (B) and 2.167 ± 0.056 in Teddy (T) goats] in both breeds. The results of breed x parity interaction showed significant differences in litter size in first [1.158 ± 0.061 (B); 1.861 ± 0.057 (T)], third [2.062 ± 0.078 (B); 2.583 ± 0.073 (T)] and average parity [708 ± 0.060 (B); 2.167 ± 0.056 (T)] in both breeds. All three loci in both breeds were found to be polymorphic and the results of breed x parity x genotype analysis showed that genotypes of all the three genes were significantly associated with litter size in all parities in both breeds. For the BMPR1B gene, heterozygous (CT) animals of Beetal and Teddy goats had the largest litter size in all three parities and the average (parity) litter size, showing the overdominance of the heterozygotes. Similarly, for GDF9 gene, heterozygous animals (AG) had the largest litter size in both breeds. For BMP15 gene homozygous carrier animals (CC) of both breeds had the highest number of kids, followed by the heterozygous (AC) genotypes. The current results show the importance of BMPR1B, GDF9 and BMP15 as the major genes that influence prolificacy in both Beetal and Teddy goats. It is suggested that these polymorphisms can be used as molecular markers to select the prolific animals in these breeds. <![CDATA[<b>Lactation performance and blood metabolites in lactating dairy cows micro-supplemented with <i>Moringa oleifera </i>leaf meal</b>]]> This study examined the effects of micro-supplementation of Moringa oleifera leaf meal on lactation performance and blood metabolites of lactating dairy cows. Thirty Jersey cows (± 40 days in milk (DIM)) were supplemented with Moringa oleifera leaf meal (M) at 0 (M0), 30 (M30) and 60 g/cow/day. The experiment lasted until 90 DIM with 14 days adaptation. Milk yield was recorded daily and samples were collected once weekly to determine milk composition and total antioxidant capacity (MTAC). Blood samples were collected on days 54, 68 and 90 in milk to determine serum total protein (TSP), albumin (Alb), immunoglobulin G (IgG) and serum total antioxidant capacity (STAC). Body weight (BW) and milk yield were not affected (P &gt;0.05) by Moringa supplementation. Moringa supplementation at M60 increased (P <0.05) milk fat and MTAC with a significant reduction in somatic cell count (SCC). Increased (P <0.05) total serum protein (TSP) and IgG with reduced (P <0.05) non-esterified fatty acids (NEFA) levels were observed in M60. Increased (P <0.05) STAC levels were noted in all groups supplemented with Moringa. Micro-supplementation with Moringa oleifera at 60 g/cow/day markedly reduced oxidative stress, which resulted in improved milk quality and immunity in lactating Jersey cows. <![CDATA[<b>Use of electrical bioimpedance analysis to evaluate the quality of bovine raw milk</b>]]> The objective of the present study was to use electrical bioimpedance analysis (BIA) as an alternative method of evaluating the quality of bovine raw milk. Fourteen lactating purebred Dutch cows were used. For the analyses of milk quality and electrical bioimpedance, 140 ml milk per mammary quarter and a homogeneous sample of each animal were collected, totalling 70 samples. The criteria used to evaluate milk quality consisted of somatic cell count (CCS), total bacterial count (CBT), fat, protein, lactose, total solids (ST) and non-greasy solids (SNG) as required by IN No 62/2011. A monofrequential 50 kHz and 800 μΑ alternating current generator was used for electrical BIAs. The temperature of the raw milk was 5 °C for all samples. Primary resistance and reactance readings were obtained. From these values, the values of impedance, conductance and phase angle were obtained. Correlation analyses were performed to determine the variables used by the regression analyses. The regression analysis was performed using raw milk components as dependent variables and BIA measurements as independent variables. Lactose, ST and SNG were the components of milk that correlated best and presented moderate prediction equations in relation to BIA variables. The prediction equations using resistance showed R2 of 0.42 and 0.45 for ST and SNG, respectively. In the prediction equation for ST and SNG, the conductance resulted in R2 of 0.45, and 0.45, respectively. Regarding impedance, the R2 of 0.42 and 0.45 were obtained for the predicted equations ST and SNG, respectively. Thus, it can be concluded that BIA has the potential to estimate the composition and quality of bovine raw milk.