Conservation of indigenous cattle genetic resources in Southern Africa's smallholder areas: turning threats into opportunities - A review

The current review focuses on characterization and conservation efforts vital for the development of breeding programmes for indigenous beef cattle genetic resources in Southern Africa. Indigenous African cattle breeds were identified and characterized using information from refereed journals, conference papers and research reports. Results of this current review reviewed that smallholder beef cattle production in Southern Africa is extensive and dominated by indigenous beef cattle strains adaptable to the local environment. The breeds include Nguni, Mashona, Tuli, Malawi Zebu, Bovino de Tete, Angoni, Landim, Barotse, Twsana and Ankole. These breeds have important functions ranging from provision of food and income to socio-economic, cultural and ecological roles. They also have adaptive traits ranging from drought tolerant, resistance to ticks and tick borne diseases, heat tolerance and resistance to trypanosomosis. Stakeholders in the conservation of beef cattle were also identified and they included farmers, national government, research institutes and universities as well as breeding companies and societies in Southern Africa. Research efforts made to evaluate threats and opportunities of indigenous beef cattle production systems, assess the contribution of indigenous cattle to household food security and income, genetically and phenotypically characterize and conserve indigenous breeds, and develop breeding programs for smallholder beef production are highlighted. Although smallholder beef cattle production in the smallholder farming systems contributes substantially to household food security and income, their productivity is hindered by several constraints that include high prevalence of diseases and parasites, limited feed availability and poor marketing. The majority of the African cattle populations remain largely uncharacterized although most of the indigenous cattle breeds have been identified.

Effect of sex and time to slaughter (transportation and lairage duration) on the levels of cortisol, creatine kinase and subsequent relationship with pork quality

The study determined the effect of sex and time to slaughter on cortisol and creatine kinase levels, and pork quality in commercial crossbred pigs. Saliva samples were before collected transportation, on arrival at the abattoir, and after a 20 hour lairage period. Cortisol levels from saliva (SC), serum (SeC) and urine (UC) were determined. Creatine kinase (CK) levels were determined from serum samples. Fifteen boars vs. 15 gilts were immediately slaughtered on arrival (SOA), and the other 15 boars vs. 15 gilts were rested for 20 h before slaughter. Meat quality parameters were also determined. In both sexes, SC significantly increased in response to time to slaughter. There was a significant interaction of sex and time to slaughter on SeC. Gilts had higher CK levels and lower muscle L* values than boars. There were correlations among baseline SC, SeC, UC and most meat quality parameters. Time to slaughter influenced levels of SC, UC, CK and pork quality between boars and gilts.

Proximate composition and variation in colour, drip loss and pH of breast meat from broilers supplemented with Moringa oleifera leaf meal over time

This study investigated the breast meat proximate composition and quality indicators in relation to response of broilers to the following dietary treatments (T): positive control (+C; with 668 mg salinomycin and 500 mg zinc bacitracin per kg of feed); Moringa oleifera leaf meal (MOLM) was fed at a low level (ML; 1–5 g/kg feed, depending on growth stage), a medium level (MM, 3 times the low level) or a high level (MH, 5 times the low level); and a negative control (–C; without supplementation) for 35 days. At postmortem, the carcass weight, and breast muscle pH at 45 min (pH45) and 24 h (pH24) were recorded. At 36 h postmortem, breast muscles were excised, weighed and stored in a refrigerator at 4°C to measure pH, colour (CIE-L*, lightness; a*, redness; and b*, yellowness) and cumulative drip loss over eight consecutive days. Chroma (C*) and hue angle (h) were calculated. The –C had the highest (P > 0.05) dressing percentage and chilled carcass weight, and ML had the lowest. Breast meat fat and energy contents were highest (P < 0.05) in +C and MOLM supplemented diets, and lowest in -C. Dietary treatments had no effect on pH at postmortem and during storage over time. Cumulative drip loss increased with each day of storage, and it was highest (P < 0.05) in +C and lowest in MH. Dietary supplementation of MOLM significantly (P < 0.05) reduced lightness, but increased redness, yellowness, chroma and the hue angle during storage over time. In conclusion, dietary supplementation of M. oleifera leaf meal had positive effects on proximate composition and shelf-life quality indicators of broiler breast meat.

Seasonal variation in coat characteristics, tick loads, cortisol levels, some physiological parameters and temperature humidity index on Nguni cows raised in low- and high-input farms

Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals (P < 0.05). Zazulwana cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms (P < 0.05). High tick loads were recorded for cows with long hairs. Hair lengths were longest during the winter season in the coastal areas of Zazulwana and Honeydale (P < 0.05). White and brown-white patched cows had significantly longer (P < 0.05) hair strands than those having a combination of red, black and white colour. Cortisol and THI were significantly lower (P < 0.05) in summer season. Red blood cells, haematoglobin, haematocrit, mean cell volumes, white blood cells, neutrophils, lymphocytes, eosinophils and basophils were significantly different (P < 0.05) as some associated with age across all seasons and correlated to THI. It was concluded that the location, coat colour and season had effects on hair length, cortisol levels, THI, HP and tick loads on different body parts and heat stress in Nguni cows.

349 SUPEROVULATORY RESPONSE AND EMBRYO QUALITY RECOVERED FOLLOWING FLUSHING NGUNI HEIFERS AND COWS

Most of the South African indigenous cattle breeds are facing genetic degradation due to unselective crossbreeding and irregular matings especially in small scale farming. The aims of the study were to compare superovulatory (SO) response, fertilization rate and to evaluate embryo quality recovered from superovulated Nguni stud cows and heifers. Nguni stud cows (n = 15) and heifers (n = 10) aged 4–6 and 2 years, respectively, were used as embryo donors for ex situ conservation. Nine days following heat observation for the first oestrus synchronisation protocol, superstimulation of donor cows and heifers were administered with a total of 350 mg of FSH (Follotropin-V®, porcine pituitary glands extract) divided into 2 injections daily 12 h apart (6 a.m. and 6 p.m.) for 4.5 days on a decreasing dosage. Two injections of prostaglandin F2α were administered on Day 3 and 4 of FSH injections. Semen was collected from 2 Nguni bulls (bull 1 and 2) and assessed by computer aided sperm analysis before artificial insemination (AI). The AI was conducted with fresh semen 3 times, 12 h apart, and the first AI was performed at the onset of oestrus. Semen from bull 1 was used to inseminate the cows, and bull 2 was used for heifers. Embryos were flushed 7 days after AI using a nonsurgical technique. Embryos were evaluated under stereo microscope and classified according to IETS standard codes (code 1, good and excellent; code 2, fair). Recovered embryos were then vitrified and stored for future use. Superovulatory response was measured by counting number of corpus lutea in each ovary. Data were analysed using 1-way ANOVA (SAS, 2003, SAS Institute Inc., Cary, NC, USA). There was no statistical difference between bull 1 (93.7%) and bull 2 (83.5%) on total sperm motility rate. Furthermore, no significant differences were recorded on fertilization rate between cows (67.5%) and heifers (53.5%). There was also no significant difference on the proportion of Nguni cows (40%) and heifers (40%) that responded to superovulation treatment. There was a significant difference on the ovary reaction (number of corpus lutea) of cows (11.3 ± 1.41) and heifers (4.0 ± 0.57). There were no significant differences recorded on the embryo quality recovered between Nguni cows (code 1, 2.5 ± 1.00; code 2, 1.3 ± 0.59) and heifers (code 1, 0.8 ± 0.41; code 2, 1.0 ± 0.36). However, cows had higher numbers of unfertilized ova than heifers (5.5 ± 1.05 and 1.8 ± 0.47, respectively) and degenerate embryos (3.7 ± 1.00 and 1.3 ± 0.39, respectively). Although superovulatory response of both Nguni cows and heifers was low, Nguni cows had higher ovarian response than heifers. Moreover, the quality of embryos recovered was similar for both Nguni cows and heifers.

Farmers' perceptions and knowledge of cattle adaptation to heat stress and tick resistance in the eastern cape, South Africa

The objective of this study was to determine the perceptions and knowledge of farmers of heat stress and tick resistance in cattle. A cross-sectional survey was conducted and 110 farmers in four villages in the sour and sweet velds of the Eastern Cape Province, South Africa were interviewed. The associations among area (municipality), gender, age, level of education, employment and religion were computed using Chi-square tests. The majority of the respondents had on average 4 bulls, 4 cows, 4 heifers, 4 calves, and 4 oxen. Milk was considered as the major (28.3%) reason for keeping cattle. Most farmers owned non-descript (72.6%), and Nguni (45.3%) cattle because of their heat tolerance (54.7%), tick resistance (54.7%), and milking ability (28.2%) traits. Excessive panting (56.6%) and disease transmission (76%) were regarded as the major effects of heat stress and tick infestation in cattle, respectively. About 50% of the respondents agreed that hair length influences tick resistance and 47.17% considered coat colour when acquiring cattle. In the sampled areas, ticks were prevalent in the summer season (93%), and 77.36% of the respondents use acaricides every fortnight. Gall sickness was reported to be a major problem in the cattle herds by 36.79% of the respondents. Our results showed that farmers in the two municipalities had knowledge of cattle adaptation to heat stress and tick resistance.

Bruising in slaughter cattle and its relationship with creatine kinase levels and beef quality as affected by animal related factors

The objective of the study was to determine the effects of animal related factors on bruising in slaughter cattle, creatine kinase (CK) and beef quality. Three hundred and twenty one cattle from three breeds (108 Bonsmara, 130 Beefmaster and 83 Brahman) were used in this study. The animals were grouped as follows: Group 1 (16 months old), Group 2 (18 months old) and Group 3 (24 months old). At exsanguinations, blood samples for CK determination were collected using disposable vacutainer tubes. Muscularis longissimus thoracis et lumborum (LTL) was collected 24 h after slaughter to determine the colour (L*, a*, and b*) and ultimate pH (pH_u) of beef. Breed, sex and age had significant effects (p<0.05) on bruising score, CK levels and beef quality. Bonsmara breed had the highest (80%) bruising score percentage, CK (705.3±80.57 U/L) and pH_u (6.3±0.05) values while the Bonsmara had the highest L* (24.8±0.78) a* (17.5±0.53) and b* (12.8±0.53) values. Higher CK levels were also observed in winter compared to summer, spring and autumn respectively. Therefore, animal factors (sex, breed and animal age at slaughter) contribute to the development of bruises and have an effect on the levels of CK and meat quality. It was also concluded that there is no significant relationship between meat parameters (L,* a*, and b*) and CK levels.

The Effects of Pre-slaughter Stress and Season on the Activity of Plasma Creatine Kinase and Mutton Quality from Different Sheep Breeds Slaughtered at a Smallholder Abattoir

The objective of the current study was to determine the effect of pre-slaughter stress, season and breed on the activity of plasma creatine kinase (CK) and the quality of mutton. One hundred and seventy-three (173) castrated sheep from Dormer (DM), South African Mutton Merino (SAMM), Dorper (DP) and Blackhead Persian (BP) sheep breeds were used in the study. The animals were grouped according to age-groups as follows: Group 1 (6 to 8 months), Group 2 (9 to 12 months) and Group 3 (13 to 16 months). Blood samples were collected during exsanguinations using disposable vacutainer tubes for CK analysis. Representative samples of the Muscularis longissimuss thoracis et. lumborum (LTL) were collected from 84 castrated sheep, of different breeds (28 per breed) 24 h after slaughter. The following physico-chemical characteristics of mutton were determined; meat pH (pH24), color (L*, a* and b*), thawing and cooking losses and Warner Braztler Shear Force (WBSF). The activity of plasma CK was significantly higher (p<0.001) in summer (1,026.3±105.06) and lower in winter (723.3±77.75). There were higher values for L* (33.7±0.94), b* (11.5±0.48) and WBSF (29.5±1.46) in summer season than in winter season; L* (29.4±0.64), b* (10.2±0.33) and WBSF (21.2±0.99). The activity of plasma CK was influenced by the type of breed with Dormer having the highest (p>0.001) levels (1,358.6±191.08) of CK. South African Mutton Merino had higher values for pH24 (5.9±0.06), L* (34.2±0.97), b* (12.2±0.50) and WBSF (26.8±1.51) and Blackhead Persian had higher values (35.5±2.17) for cooking loss (CL%) than the other breeds. Computed Principal Component Analyses (PCA) on the activity of plasma CK and physico-chemical characteristics of mutton revealed no correlations between these variables. However, positive correlations were observed between pH24, L*, a*, b*, CL% and WBSF. Relationships between pre-slaughter stress, CK activity and physico-chemical characteristics of mutton were also observed. It was therefore concluded that although mutton quality and creatine kinase were not related, pre-slaughter stress, season and breed affected the activity of creatine kinase and mutton quality.

Atherogenicity index and health-related fatty acids in different stages of lactation from Friesian, Jersey and Friesian×Jersey cross cow milk under a pasture-based dairy system

The objective of the study was to investigate the effect of stage of lactation on the fatty acid profiles of milk from Friesian, Jersey and Friesian×Jersey cows. Linoleic acid in pastures was highest in the second phase which coincided with mid-lactation days (p<0.05). Highest milk moisture content and lowest fat free dry matter content was seen in early lactation (p<0.05). Higher fat content was observed in late lactation than early lactation. Highest butyric, caproic, linoleic, omega-6 and polyunsaturated fatty acids were observed for milk from Friesian cows. Highest conjugated fatty acids, α-linolenic acid, linoleic acid, saturated fatty acids, polyunsaturated fatty acids, omega-6, and omega-3 were observed in early lactation. Atherogenicity index and desaturase activity indices were highest in late lactation. In conclusion, stage of lactation and genotype affected milk health-related fatty acid profiles.

Fatty acid composition and oxidative stability of breast meat from broiler chickens supplemented with Moringa oleifera leaf meal over a period of refrigeration

Effects of diets supplemented with or without Moringa oleifera leaf meal (MOLM) on fatty acid (FA) composition and oxidative stability of broiler breast meat during refrigerated storage was determined. Dietary treatments (T) were as follows: T1, positive control, 668g/ton Salinomycin and 500g/ton Albac; T2, T3 and T4 contained graded levels of MOLM at 1%, 3% and 5% of dry matter (DM) intake, respectively; and T5, a negative control (0% additives). Oxidative stability was evaluated by thiobarbituric acid reactive substances (TBARS) on day (D) 1-8 of storage at 4°C; and FA analysis was done on samples obtained on D1 and D8. Significant effects on TBARS were noted on day (D) 1, 3, 4 and 7; increased with increasing storage time, and with increase in MOLM supplementation. Highest (P<0.05) C18:0 and C15:0 levels were noted on D1 in T2; C20:0 in T4 on D8; C20:2, C20:3n6 and C22:6n3 in T2; C18:3n6 and P/S ratio in T4 on D1; and n-3 in T3. Thus, despite the high SFA content, additive supplementation of M. oleifera leaf meal up to 5% of the bird's DMI improved the FA profile and reduced lipid oxidation in broiler breast meat.

Effects of transportation time, distance, stocking density, temperature and lairage time on incidences of pale soft exudative (PSE) and the physico-chemical characteristics of pork

The study determined the effects of transportation time, distance, stocking density, temperature and lairage time on incidences of PSE and pork quality. Frequencies of PSE cases in stocking density categories within transport duration classes were determined. General linear models, regression and the principal component (PC) analysis were used to analyse the data. Highest incidences of PSE were recorded in autumn season while lowest incidences were recorded in the spring season. Transportation time and stocking density significantly affected pHu and ultimately PSE incidences although there were no interactive effects. Highest risks of PSE occurrence were observed with more space allowance. The highest incidences of PSE were observed for animals that had travelled for two hours while the PSE cases were lower in animals that travelled for longer times. Distance travelled and transportation time had significant effects (P<0.05) on thawing loss (TL) % of pork. No relationships were reported between the other pre-slaughter variables and pork quality attributes. With the exception of transportation time and distance travelled which had a positive relationship with TL%, variation in other pre-slaughter variables did not affect meat quality variables. The risks of PSE occurrence were dependent on stocking density and transportation time.