C. Mapiye

Seroprevalence of tick-borne diseases in communal cattle reared on sweet and sour rangelands in a semi-arid area of South Africa

A survey was conducted to determine the seroprevalence of tick-borne diseases (TBD) in Nguni and non-descript cattle on the sweet and sour communal rangelands across seasons. Body condition scores, bodyweights, packed cell volume (PCV) and antibodies to B. bovis, B. bigemina, Ehrlichiaruminatium and Anaplasma marginale were determined seasonally in 144 cattle raised on communal rangelands from August 2007 to April 2008. Approximately 45% of the cattle were seropositive for B. bovis, 46% for B. bigemina and 26% for A. marginale. All animals were seronegative for E. ruminantium. Nguni cattle had lower (P<0.05) seroprevalence for A. marginale and B. bigemina in the cool-dry and hot-wet seasons. Cattle in the sweet rangeland had significantly lower seroprevalence of B. bovis and B. bigemina in all the seasons. Infection with B. bovis and B. bigemina negatively affected (P<0.05) bodyweight and body condition scores whilst B. bovis and A. marginale infections significantly affected PCV. The seroprevalence of TBD was lower in the Nguni breed. More work is required to understand the mechanisms of the adaptation and possible resistance of Nguni cattle to TBD.

Meat quality of Nguni steers supplemented with Acacia karroo leaf-meal

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.

Supplements containing Acacia karroo foliage reduce nematode burdens in Nguni and crossbred cattle.

The objective of this study was to compare nematode worm burdens in Nguni and crossbred cattle supplemented with Acacia karroo leaf meal. Eighteen Nguni (274.4 ± 17.34 kg) and 12 crossbred (230.5 ± 14.62 kg) steers aged 19 months were allocated to three dietary treatments: A. karroo leaf meal, sunflower cake and control with no supplement. Steers in all the treatments grazed on natural pasture whereas those on A. karroo leaf meal and sunflower cake diets were given an additional 1.5 kg and 650 g of feed, respectively, to supply 150 g of protein per day for 60 days. Faecal samples collected from the steers’ recta every fortnight were examined for nematode egg types using the modified McMaster technique. At slaughter, the abomasa and intestines were collected, opened and washed for worm identification. Nguni steers supplemented with the A. karroo leaf meal diet had the lowest mean strongyles egg counts and mean total egg counts (P < 0.05). Steers that received the A. karroo leaf meal and sunflower cake diets had lower Haemonchus contortus and Oesophagostomum colombianum worm burdens than those that received the control diet (P < 0.05). Mean strongyles and Strongyloides egg counts, and H. contortus and Oes. colombianum worm counts were negatively correlated with average daily gain and body condition scores (P < 0.05). Generally, Nguni cattle supplemented with A. karroo leaf meal had the lowest egg loads and worm burdens. It was concluded that supplementing cattle with A. karroo could reduce nematode burdens.

Tick loads in cattle raised on sweet and sour rangelands in the low-input farming areas of South Africa

The objective of this study was to compare tick loads and prevalence in Nguni and non-descript cattle in the sweet (palatable throughout the year) and sour (palatable only in the rainy season) communal rangelands of the Eastern Cape Province, South Africa. Engorged adult female ixodid ticks were collected and identified seasonally from 144 cattle raised on sweet and sour rangelands from August 2007 to April 2008. Three tick species were identified in the sweet and sour rangelands namely Rhipicephalus appendiculatus, Rhipicephalus (Boophilus) decoloratus, and Rhipicephalus evertsi evertsi with prevalences of 71.1%, 29.2%, and 40.2%, respectively. Hyalomma species (19.0%) occurred only in the sour rangeland. Higher tick counts were recorded in the hot–wet season than in the cool–dry season (P < 0.05). Cattle in the sweet rangeland had significantly lower tick loads than those in the sour rangeland in all the seasons except the hot–dry season. The Nguni breed had lower (P < 0.05) tick loads of R. appendiculatus in the hot–wet and post-rainy season and Hyalomma species in all seasons than the non-descript cattle. The use of a tick-resistant Nguni breed in the integrated control of ticks on cattle in the communal areas of South Africa is recommended.

Ovarian activity, conception and pregnancy patterns of cows in the semiarid communal rangelands in the Eastern Cape Province of South Africa.

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.