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.

Differences in Health-related Fatty Acids, Intramuscular Fat and the Physico-chemical Quality in Mutton as Affected by Season, Place of Purchase and Meat Portion

The objective of the study was to determine the quality and fatty acid profiles of mutton cuts purchased from rural and urban localities in South Africa. Five hundred and ten samples were collected in four seasons from both rural and urban shops and butcheries. Samples were immediately transported to the laboratory in cooler boxes with ice where the following physico-chemical characteristics of mutton were determined; meat pH, color (L*, a*, and b*), cooking losses and Warner Braztler shear force and replicates stored at −20°C pending fatty acid analysis. Meat L* values were lowest (24.7±0.49) in winter and highest (32.2±0.49) in spring. The loin and sirloin cuts recorded the highest intramuscular fat whilst rib and leg cuts recorded the lowest intramuscular fat. In conclusion intramuscular fat, fatty acid profiles and physico-chemical quality of mutton were significantly affected by season and meat portion and not necessarily by the locality and class of shop.

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.

Influence of Municipal Abattoir Conditions and Animal-related Factors on Avoidance-related Behaviour, Bleeding Times at Slaughter and the Quality of Lamb Meat

The objective of this study was to determine the effect of municipal abattoir conditions and animal factors on avoidance-related behaviour (AB) of sheep at slaughter, bleeding times (BT) and mutton quality. The behaviour of 66 castrates and 19 ewes of different age categories was observed at three stages of slaughter. Higher behaviour scores indicated higher levels of AB. Time intervals between the start of blood flow and the time the flow changed from a constant stream into drips were recorded as BT. Thirty two meat samples were obtained to measure quality variables. These were colour (L*, a* and b*), pH₂₄, temperature, cooking loss (CL) and tenderness. Correlations were determined between BT and meat quality variables. Animal behaviour at slaughter differed with breed, gender and age group. Avoidance behaviour was higher in the Dorper breed than in both the Merino breed and their crosses. It was also higher in younger (<10 months) lambs than in older sheep. Castrates were more aggressive or in panic than ewes. Castrates had longer (72.6±0.53 s) BT than the ewes (63.6±2.82 s). Ewes had higher CL (39.8±1.04%) values than castrates (35.1±0.95%). Meat from castrates was tougher (32.6±1.95 N) than the meat from ewes (24.3±1.16 N). There were no significant correlations obtained between BT and meat quality variables. It can therefore be concluded that abattoir conditions, breed, age and gender had an effect on AB at slaughter. Gender had an effect on BT and mutton quality.

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.

Body and fleece weights of woollen sheep in veld communal rangelands of the Eastern Cape Province

The objective of this study was to determine the live weight, body condition scores (BCS) and fleece weight of sheep in four smallholder farming communities of Eastern Cape Province, South Africa. Among the four communities studied, two (Roxeni and Tyabane) were in sweetveld and other two (Luzi I and Luzi II) were in a sourveld. Roxeni and Luzi communities were also engaged in the ram exchange project with the National Wool Growers Association (NWGA). Sixty crossbred ewes and 20 non-descript ewes aged 2 to 3 years were randomly selected from the four communities studied and were measured during their annual shearing in October. They were assessed for average greasy fleece weight per head, body condition score and live weight after shearing. Roxeni sheep were heavier (39.9 ± 1.10 kg) than Tyabane sheep (29.8 ± 1.10 kg). Sheep from Tyabane had the lightest (P <0.05) fleece weight (1.0 ± 1.10 kg) than Roxeni sheep (3.1 ± 1.10 kg). The 2-year-old ewes had similar (P ≥ 0.05) live weight to that of the 3-year-old ewes. However, the 3-year-old ewes had higher (3.3 ± 0.11) (P < 0.05) body condition scores than the 2-year-old ewes (2.8 ± 0.10). Two-year-old ewes also had lower (1.9 ± 0.11 kg) (P < 0.05) fleece weight than the 3-year-old ewes (2.3 ± 0.10 kg). It was concluded that sheep that were raised in the sweetveld had higher live and fleece weights than the ones that were raised on the sourveld. The communities that were engaged on ram exchange project had sheep with higher live weights, body condition score and fleece weight.

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.