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ABSTRACT: Nguni cattle are known to be more resistant to ticks than Bonsmara cattle, even if the immunological mechanisms responsible for this phenomenon are not fully understood. Cutaneous hypersensitivity responses to unfed larval extracts (ULE) of the ticks Rhipicephalus decoloratus and Rhipicephalus microplus were investigated in Nguni and Bonsmara cattle to improve knowledge on the immunity to ticks. Hypersensitivity reactions were induced by intradermal inoculation of 0.1ml of ULE of R. decoloratus and R. microplus ticks (50μg protein) in the right and left ear, respectively, of 8-9-month-old Nguni (n=11) and Bonsmara (n=9) heifers. Ear thickness was measured using callipers before and 0.5, 1, 6, 24, 48, and 72h post inoculation (PI). Bonsmara cattle showed a more intense immediate reaction with maximum response at 1h PI and no delayed hypersensitivity reaction. Nguni heifers, conversely, presented a less intense immediate reaction with maximum response at 1h PI, and a delayed hypersensitivity reaction at 72h PI. Reactions to R. decoloratus ULE produced a more intense skin response than to R. microplus in both breeds at all time intervals. Nguni cattle showed lower tick infestation indicating higher tick resistance than Bonsmara cattle. Delayed hypersensitivity reaction could be associated with superior tick resistance in the Nguni breed, while immediate hypersensitivity reaction could be associated with increased tick susceptibility in the Bonsmara breed. This study indicates the need for further investigations on the correlation of tick resistance and cellular immune responses to tick infestation in Nguni cattle.
Ticks and Tick-borne Diseases 02/2013;
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Poultry Science 05/2012; 91(5):1277. · 1.73 Impact Factor
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ABSTRACT: The objectives of this study were to analyze the genetic diversity and structure of South African conserved and field chicken populations and to investigate the maternal lineages of these chicken populations. Four South African conserved chicken populations (n = 89), namely, Venda (VD_C), Ovambo, Naked Neck, and Potchefstroom Koekoek from the Animal Production Institute of the Agricultural Research Council, and 2 field populations, the Venda and Ovambo (OV_F), from which the Ovambo and the Venda conservation flocks were assumed to have been sampled, were genotyped for 460 bp of the mitochondrial DNA (mtDNA) D-loop sequence. Haplotypes of these chickens were aligned to 7 Japanese and 9 Chinese and Eurasian chicken mtDNA D-loop sequences taken from GenBank and reflecting populations from presumed centers of domestication. Sequence analysis revealed 48 polymorphic sites that defined 13 haplotypes in the South African chicken populations. All 6 South African conserved and field chicken populations observed were found to be polymorphic, with the number of haplotypes ranging from 3 for VD_C to 8 for OV_F. The lowest haplotype diversity, 0.54 ± 0.08, was observed in VD_C chickens, whereas the highest value, 0.88 ± 0.05, was observed in OV_F chickens. Genetic diversity between the 4 South African conserved and 2 field chicken populations constituted 12.34% of the total genetic variation, whereas within-population diversity constituted 87.66% of the total variation. The median network analysis of the mtDNA D-loop haplotypes observed in the South African conserved and field populations and the reference set resulted in 5 main clades. All 6 South African chickens were equally represented in the major clade, E, which is presumed to be of Indian subcontinent maternal origin and may have its roots in Southeast Asia. The results showed multiple maternal lineages of South African chickens. Conservation flocks and field chicken populations shared the major haplotypes A, D and E, which were presumed to be of Chinese, Southeast Asian, and Indian subcontinental origin.
Poultry Science 10/2011; 90(10):2189-94. · 1.73 Impact Factor
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ABSTRACT: The objective of this study was to determine the levels of catecholamines and their relationship to beef quality in Nguni steers fed on Acacia karroo leaves. A total of 30 19-month-old steers were randomly assigned to A. karroo leaves (AK), sunflower cake (SF) and the control with no supplement (CN) diets. The AK and SF diets provided the steers with an additional 150 g of protein per day for 60 days. Catecholamine levels were determined from urine samples collected from each steer before and after slaughter. The Musculus longissimus thoracis et lumborum was sampled for selected meat quality measurements. Nguni steers on the CN diet had higher (P < 0.05) concentrations of post-mortem urinary norepinephrine and dopamine compared with those that received the AK and SF diets. Norepinephrine was negatively linearly related (P < 0.05) to the Warner-Bratzler shear force value of meat aged for 21 days and cooking loss of meat aged for 2 days (CL2) in steers that were given the SF diet. Meat pH and drip loss values were inversely related (P < 0.05) to epinephrine concentration in steers that received the AK diet. Dopamine concentration was negatively linearly related (P < 0.05) to water holding capacity and CL2 for steers on the CN diet. For steers on the CN diet, lightness (L*) values increased (P < 0.05) with increase in dopamine concentration. It was concluded that stress responsiveness and its relationship to certain beef quality attributes could be positively manipulated by supplementation with A. karroo leaves.
animal 08/2011; 5(9):1361-9. · 1.74 Impact Factor
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ABSTRACT: The effect of four castrated goat genotypes and sunflower cake supplementation on goat meat quality was determined. Supplemented Boer (BOR) and Xhosa-Boer cross (XBC) goats had significantly higher (P<0.05) SLW and CDM than non-supplemented groups. The Xhosa lop-eared (XLE) and Nguni (NGN) goats had higher pH24 (P<0.05) than BOR and XBC goats. For each genotype, the sunflower cake supplemented and non-supplemented goats had similar a* values, except for the XLE goats. In the XLE goats, the a* values were lower in the sunflower cake supplemented goats. Sunflower cake supplemented BOR goats had higher L*values than their non-supplemented counterparts (P<0.05). The sunflower cake supplemented BOR and NGN goats also had higher b* values as compared to their non-supplemented counterparts. In comparison with the Boer goat, the XLE and NGN goats had lower CDM, L* and WBF values but generally had higher CL and a* values. Sunflower cake supplementation improved meat quality attributes of the goats.
Meat Science 07/2011; 90(1):204-8. · 2.28 Impact Factor
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ABSTRACT: The objective of the study was to evaluate the effect of genotype and supplementary feeding on
sensory scores of chevon from different indigenous goat genotypes prepared using different thermal
treatments. 48 6-month-old Xhosa lop-eared (XLE), Nguni (NGN), Xhosa-Boer cross (XBC) and Boer
(BOR) castrated goats with a body weight range of between 20 and 25 kg was used in the study. Half of
the goats were supplemented with 200 g per head per day of sunflower cake. A consumer sensory
evaluation was done with consumers of different ages, tribes and gender. In the non-supplemented XLE
and BOR goats, the aroma intensity scores of the fried meat were significantly higher than the cooked
meat. Female respondents gave higher (P < 0.05) scores than male respondents for both cooked and
fried meat on aroma intensity. Shona consumers gave higher (P < 0.05) aroma intensity scores than the
Xhosa and the Zulu consumers for both cooked and fried meat. In the non-supplemented goats, fried
meat for all the genotypes was superior (P < 0.05) to the cooked meat for initial impression of juiciness.
The age and gender of respondents and thermal treatment influenced initial impression of juiciness
scores (P < 0.05). In meat from the non-supplemented XLE and NGN goats, the consumers gave higher
(P < 0.05) muscle fibre and overall tenderness scores in cooked meat than the fried meat.
AFRICAN JOURNAL OF BIOTECHNOLOGY 05/2011; 10(21-ISSN 1684-5315):4436-4443. · 0.57 Impact Factor
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ABSTRACT: The objective of the current study was to determine the relationship between off-flavor descriptors and flavor scores in beef aged for 2 and 21 days from Nguni, Bonsmara and Angus steers raised on natural pasture. Fifteen steers each of Bonsmara and Angus and 25 steers of Nguni were kept at the University of Fort Hare Farm for 12 months until slaughter. The M. longissimus thoracis et lumborum was sampled postmortem for flavor evaluation. There were associations (P < 0.05) between off-flavor descriptors and off-flavor scores, off-flavor descriptors and aroma scores. There were, however, no (P > 0.05) associations between beef from the three cattle breeds and off-flavor descriptors, flavor scores and off-flavor descriptors, aging periods and off-flavor descriptors. It can be concluded that off-flavor description is uniform across breeds and aging periods. Furthermore, off-flavor description is related to off-flavor scores and aroma scores.PRACTICAL APPLICATIONSFlavor is one of the components of sensory evaluation that affect beef acceptability by consumers. In lean meat, thermal oxidation of long-chain fatty acids occurs, thereby leading to undesirable aroma/flavor formation, which may affect meat palatability. Off-flavors are undesirable and negatively affect the consumers’ decision on purchasing beef. Therefore, flavor evaluation should include off-flavor and its descriptors. Off-flavors develop with aging and it is therefore important to establish when meat should be consumed after slaughter. When examining factors that affect off-flavor production, it may be more beneficial to look at the total number of samples that are detected with off-flavors rather than the sensory off-flavor score only. Establishing relationships between breed, aging, flavor scores and off-flavor descriptors is therefore important in meat production and consumption.
Journal of Muscle Foods 06/2010; 21(3):424 - 432. · 0.50 Impact Factor
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ABSTRACT: The objective of the study was to determine the meat quality of Nguni steers supplemented with Acacia karroo leaf-meal. Thirty 19-month old steers were randomly assigned to A. karroo leaf-meal (AK), sunflower cake (SF) and a control (CN) diets. Steers on the AK and SF diets were given an additional 150 g of protein per day for 60 days. The steers were slaughtered at 21 months and the m.longissimus thoracis et lumborum was sampled for meat quality measurements. Steers that received SF diet had lighter-coloured (L*) (P<0.05) meat than those on AK and CN diets. The highest redness (a*) (17.3+/-0.29) values were recorded in steers supplemented with AK compared to those that received SF and CN diets. Diet had no effect on pH, drip loss, water holding capacity, sarcomere length, muscle bundle areas, myofibrillar fragment length, Warner-Bratzler shear force and cholesterol values. Steers supplemented with AK (22.4+/-0.08%) and SF (22.5+/-0.08%) had higher (P<0.05) meat protein content than those on the CN (20.2+/-0.08%) diet. Highest muscle fibre area (3472.6+/-119.51 microm(2)), fat content (1.2+/-0.11%) and cooking loss (25.2+/-0.73%) of meat aged for 2 days were recorded in steers given the SF diet compared to those on the AK and CN diets. Supplementing Nguni cattle with A. karroo leaf-meal produced beef of comparable quality to natural pasture alone but with a fresher appearance and higher protein content.
Meat Science 04/2010; 84(4):621-7. · 2.28 Impact Factor
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ABSTRACT: The objective of the study was to determine the effect of season on faecal egg counts and biochemical profiles in indigenous Nguni goats of South Africa. Body weights, body condition scores, faecal and blood samples were collected from 96 goats. Faecal samples were analysed for nematodes and trematodes. Blood was analysed for packed cell volume (PCV), glucose, cholesterol, total protein, albumin, globulin, urea and creatinine. Significantly higher total protein and globulin values were recorded in the wet than the dry season. A significant positive correlation was recorded between body condition scores and albumin concentrations. Season had an effect on glucose, globulin, TP, creatinine, PCV and FEC of Nguni goats. It, therefore, is imperative to put measures in place to counteract the drop in any of these parameters, with season, if productivity of the indigenous goats is to be maintained. Further studies are required to determine the parasites causing chronic health challenges that were evidenced by elevated globulin concentrations in the flock studied. Since the high globulin levels were not accompanied by clinical cases, the reference levels used might be inappropriate for the indigenous Nguni goats.
South African Journal Of Animal Science 01/2010; 40. · 0.24 Impact Factor
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ABSTRACT: The objective of the study was to determine genetic diversity within South African indigenous chicken populations and the effectiveness of the current conservation flocks in capturing the available diversity in the founder populations. Two chicken populations, Venda (VD_C) and Ovambo (OV_C) conservation flocks (n = 56) from the Animal Production Institute in Irene and two founder population from which these conservation flocks were sampled; Venda (VD_F) and Ovambo (OV_F) field populations (n = 72) were genotyped for 29 autosomal microsatellite markers. All microsatellites typed were found to be polymorphic. A total of 213 alleles were observed for all four populations. The mean number of alleles per population ranged from 3.52 ± 1.09 (VD_C) to 6.62 ± 3.38 (OV_F). Mean observed (H O) and expected (H E) heterozygosity in the conservation flocks were 0.55 and 0.57 respectively. The corresponding values for the founder population were 0.62 and 0.68. The observed within population diversity measures indicated that field populations are more diverse than conservation flocks. The Reynolds genetic distance (D Reynolds) between conservation flocks and field population observed was 0.22 between VD_C and VD_F and 0.09 between OV_C and OV_F. STRUCTURE was used to cluster individuals to 2 ≤ K ≤ 5. The most probable clustering was found in K = 3, in which the populations were grouped into three clusters. VD_C and OV_C conservation flocks separated as independent clusters, while VD_F and OV_F field populations formed one cluster for any K value. Clustering analysis indicated a clear subdivision of the conservation flocks and field population into genetically distinct populations. The present study suggests that conservation flocks are less diverse compared to field populations.
South African Journal Of Animal Science 01/2010; 40. · 0.24 Impact Factor
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ABSTRACT: A study was conducted to determine the seasonal trends in ovarian activity, conception and pregnancy status of cows on communal rangelands in the Eastern Cape Province of South Africa. Ovarian activity and pregnancy status of 200 cows were determined through trans-rectal palpation in June, and October 2007 and January 2008. Month of conception was obtained by subtracting the estimated age of the foetus from the month when pregnancy diagnosis was performed. Body weights and body condition scores (BCS) were collected every month between March 2007 and January 2008. Although cows in the perennial grasslands had higher (P<0.05) body weights and BCS than those in the annual grasslands, they had a significant weight and condition loss between March and October. More than 90% of the cows in the annual grasslands were cycling in January (P<0.05). Over 60% of the cows in the perennial grasslands conceived between December and March compared to 46% in the annual grasslands. About 40% of the cows were pregnant in June in the annual and perennial grasslands. There were more cycling and pregnant cows with a BSC of 3 in the perennial grasslands in June and October compared to annual grasslands (P<0.05). Odds ratio estimates of cows exhibiting ovarian activity and pregnancy in the communal areas were highest for BCS. It was concluded that most cows conceived and exhibited ovarian activity between November and March, especially in the perennial grasslands. Future research should focus on supplementary feeding using locally available feed resources to improve cow reproductive performance in the dry months, particularly in the annual grasslands.
Animal reproduction science 08/2009; 118(2-4):140-7. · 1.56 Impact Factor
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ABSTRACT: A study was conducted to compare cholesterol and fatty acid levels of beef from three cattle breeds raised on natural pasture. Thirty-four, twenty-nine and fourteen steers each of Nguni, Bonsmara and Angus, respectively, were slaughtered at 18 months. There were no (P > 0.05) breed differences for the cholesterol and intramuscular fat (IMF) levels. The fatty acid profiles were similar (P > 0.05) among the three breeds except that beef from Nguni steers had higher (P < 0.05) docosahexaenoic acid content than beef from the other two breeds while beef from Bonsmara steers had the highest (P < 0.05) heptadacenoic acid content. It can be concluded that there were no breed differences on cholesterol and most fatty acids.
Journal of Food Composition and Analysis 05/2009; 22(4):354-358. · 2.08 Impact Factor
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ABSTRACT: Farmer perceptions on milk production and calf rearing practices on communal rangelands in the smallholder areas of the Eastern Cape Province, South Africa were evaluated on a total of 218 cattle farmers using structured questionnaires, semi-structured interviews with key informants and personal observations. Nearly 70% of the households in the small-scale areas milked twice a day compared to 60% in the communal areas. About 62% of the interviewees weaned calves between 6 and 12 months of age. Milk yield/cow/day (7.5 +/- 0.5 litres), fresh milk consumption/household/day (3.2 +/- 0.5 litres) and sales/household/day (3.1 +/- 1.1 litres) were highest in the sour-veld, small-scale farms (P < 0.05). Sour milk consumption/household/day (2.6 +/- 0.2 litres) and sales/household/day (0.8 +/- 0.2 litres) were significantly high in communal farms with a sour-veld. It was concluded that, calf rearing practices were poor and milk yield, consumption and sales were generally low and varied with production system and rangeland type. Further research is required to improve calf management practices, cow nutrition, milk yield and quality and how milk production can be used as a toll for rural development in the smallholder areas of South Africa.
Tropical Animal Health and Production 04/2009; 41(7):1475-85. · 1.12 Impact Factor
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ABSTRACT: The objective of the study was to compare the functions and management systems of goats in Chirumanzu district in Zimbabwe and, Alfred Nzo and Amatole districts in the Eastern Cape Province of South Africa. Data were collected using participatory rural appraisal techniques and direct observations. In addition, structured questionnaires from 344 households as follows; 69 from Alfred Nzo district, 144 from Amatole district and 132 from Chirumanzu district were also used to retrieve information from farmers. There were more female goat owners in male-headed households in Chirumanzu (75%) than in Amatole (27%) and Alfred Nzo (30%). Mean goat flock sizes per household were markedly high in Amatole (14.0 +/- 0.31) and Alfred Nzo (14.1 +/- 1.42) as compared to Chirumanzu (4.7 +/- 0.30). There were positive correlations (r = 0.30 for Amatole, r = 0.34 for Alfred Nzo and r = 0.25 for Chirumanzu; P < 0.05) between goat flock sizes and cattle herd sizes kept per household. Seventy-nine and 78% of households in Amatole and Alfred Nzo kept goats mainly for initiation ceremonies, respectively. Nearly all (95%) of the households in Chirumanzu reared goats for household consumption. Goat houses in all the districts were poorly constructed. Farmers' perceptions showed that most goat mortalities were mainly caused by gastrointestinal parasites and tick-borne diseases, especially heartwater. About 29, 15 and 27% of households in Alfred Nzo, Amatole and Chirumanzu, respectively, owned bucks. There were no formal markets for goats in the three districts. Chirumanzu had more females owning goats than the other two districts. No adolescents owned goats in all the three districts. Adolescent boys participated in the management of goats more than adolescent girls across the three districts. Differences in the importance of goats among countries and regions should be borne in mind when designing goat improvement and rural development programmes.
Tropical Animal Health and Production 03/2009; 41(7):1381-91. · 1.12 Impact Factor
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ABSTRACT: The objective of the study was to determine monthly changes in body condition scores, body weights and on the prevalence of internal parasites in Nguni, Bonsmara and Angus steers raised on sweetveld. Body condition scores (BCS), body weights (BW), packed cell volume (PCV) and monthly faecal egg counts (FEC) were determined in 25 Nguni, 15 Bonsmara and 15 Angus steers. Nguni and Bonsmara steers maintained their body condition throughout the study, while the Angus lost condition. The Nguni had the highest PCV levels. The PCV levels tended to decline during the rainy season for all the breeds. The FEC were generally low. Fasciola spp. and strongyle eggs were found in 16.3 and 54.6% of the collected faecal samples, respectively. Of the three breeds, Nguni steers had the lowest parasite infestation levels, with the Bonsmara being more susceptible than the other two breeds. Generally, the egg counts observed throughout the study were low.
Tropical Animal Health and Production 02/2009; 41(7):1169-77. · 1.12 Impact Factor
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ABSTRACT: Despite the fact that about 64% of goats in sub-Saharan Africa (SSA) are located in rural arid (38%) and semi-arid (26%) agro-ecological zones and that more than 90% of goats in these zones are indigenous, information on indigenous breeds is inadequate. This paper reviews the social and economic importance of goats to the communal farmer and assesses the potential of using goats in rural development in Southern Africa. Farmers in Southern Africa largely use the village goat management system. There are various goat breeds in Southern Africa, of which the Mashona, Matabele, Tswana, Nguni and the Landim are the dominant ones. It is, however, not clear if these breeds are distinct. Major constraints to goat production include high disease and parasite prevalence, low levels of management, limited forage availability and poor marketing management. Potential research areas that are required to ensure that goats are vehicles for rural development include evaluation of constraints to goat production, assessing the contribution of goats to household economies and food securities throughout the year, genetic and phenotypic characterisation of the indigenous breeds to identify appropriate strains and sustainable methods of goat improvement through either selection or crossbreeding.
Tropical Animal Health and Production 01/2009; 41(7):1157-68. · 1.12 Impact Factor
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ABSTRACT: The current study compared sensory characteristics and their relationships with physical meat characteristics of beef from Nguni and Bonsmara steers. Nguni beef was more (P < 0.05) tender than Bonsmara beef after ageing for 2 and 21 days, and had higher (P < 0.05) intramuscular fat (IMF; 1.12%) than Bonsmara beef (1.07%). Nguni beef had higher (P < 0.05) sensory scores than Bonsmara beef after ageing for 2 days. There were no (P > 0.05) relationships between IMF and sensory characteristics. Aroma intensity, impression on juiciness and tenderness-related scores were affected (P < 0.05) by pH. There were significant (P < 0.05) correlations between most physical meat characteristics and sensory characteristics. Nguni beef had better sensory scores than Bonsmara beef for beef aged for 2 days. While most physical meat characteristics were correlated to sensory scores, all sensory scores were not significantly correlated to IMF.
animal 11/2008; 2(11):1700-6. · 1.74 Impact Factor
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ABSTRACT: The relationship between stress responsiveness and beef quality of 40 Nguni, 30 Bonsmara and 30 Angus steers was determined. The L(∗) values, pHu, cooking loss (CL) and Warner-Bratzler shear force (WBSF) were determined. Catecholamine levels were determined from urine samples collected at slaughter. Bonsmara steers had the highest (P<0.05) levels of catecholamines with respective epinephrine, norepinephrine and dopamine concentrations of 10.8, 9.7 and 14.8nmol/mmol. Nguni steers had the lowest (P<0.05) levels of catecholamines, with respective catecholamine concentrations of 5.1, 4.3 and 4.0nmol/mmol. In the Nguni steers, there were significant (P<0.05) correlations between catecholamines and L(∗) and between dopamine and tenderness in meat aged for two days (WBSF2). In the Bonsmara, dopamine was correlated (P<0.05) pHu, WBSF2 and CL. No significant correlations were found in the Angus. Therefore the relationship between stress responsiveness and certain beef quality traits may not be similar in different breeds.
Meat Science 11/2008; 81(4):653-7. · 2.28 Impact Factor
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ABSTRACT: The objective of the current study was to determine the effect of quantitative feed restriction on the performance of broilers. A total of 270 unsexed broilers were randomly allocated to three treatments: with no feed restriction (T1), one week (T2) and two (T3) weeks of feed restriction from 22 days of age and then fed ad libitum until the age of 42 days. Treatments were replicated three times with 30 birds per replicate. Birds were fed with starter, grower and finisher diets. The feed consumed and body weights were recorded every week from the third to the sixth week. The average daily gain (ADG), average daily feed intake (ADFI) and the feed conversion ratio (FCR) were computed for each week. At Week 6, body weights of T3 birds were similar (P>0.05) to those of T1 and T2 birds. There were also no treatment effects on the ADG at Week 6. In addition, no treatment effects (P>0.05) were observed on ADFI at each stage of growth. Since ADFI and FCR were similar among the three groups, it was concluded that feed restriction by limiting the time to eat was not successful. There was also no evidence of compensatory growth in the restricted groups.
Tropical Animal Health and Production 08/2008; 41(3):379-84. · 1.12 Impact Factor
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ABSTRACT: The effects of breed and ageing on beef cooking loss components were investigated. Correlations among the beef cooking loss components were also determined. Longissimus thoracis et lumborum (LTL) muscle steaks from Nguni, Bonsmara and Angus steers were prepared by an electric oven-broiling method using direct radiant heat at 260°C. They were placed in an oven pan on a rack to allow meat juices to drain during cooking and placed in the pre-heated oven 90 mm below the heat source. Raw and cooked weights were recorded. Percentage cooking loss, thawing loss, drip loss and evaporation loss were determined. Beef cooking loss components were affected (P<0.05) by ageing with meat aged for two days having higher (P<0.05) losses than meat aged for 21 days. Cooking loss components were not (P>0.05) affected by breed. There were no (P>0.05) significant correlations among the cooking loss components.
African journal of agricultural research 07/2008; 3:416-420. · 0.08 Impact Factor
