Free State research into the relationship between hide thickness and tick resistance in cattle found Drakensbergers and Afrikaners are well-protected by their thicker hides and sleeker coats. Annelie Coleman spoke to researcher Liesel Foster.
Significant differences in body condition score, hide thickness and tick counts in Afrikaner, Braford, Drakensberger and Charolais cattle was found by a team of researchers from the Central University of Technology and the University of the Free State.
Ten heifers from each breed were used in the study on the farm Quaggafontein in the Zastron district. The animals were selected from southern Free State studs to guarantee trueness to type and ensure they were well adapted to the area. Measurements were taken over seven months. Coats were scored once in winter and four times in summer due to breed differences in the hair-shedding process. Scoring used a linear scale from 1 (extremely short coat) to 7 (very woolly). Body condition was measured on a score of 1 (emaciated) to 9 (obese) and determined as thin (1 to 3), borderline (4), optimum (5 to 6) and fat (7) (see box: Body condition simplified). Hide thickness and tick counts were also monitored.
The animals were allowed to become naturally infested with ticks, except for patch treatments for two months to contain infestations by Boophilus decoloratus, Hyalomma maginatum rufipes and Rhipicephalus evertsi. Two researchers counted and recorded all visible ticks on five occasions for a month. The species weren’t specified and the ticks weren’t removed.
Breeds’ coat scores differed significantly. The Afrikaner had the lowest on four of the five sampling days, while the Charolais had the highest throughout the study. The coat scores were affected by the changing seasons, decreasing from August to February. Previous studies by Turner and Schleger (1960) show that although coat score could be affected by season, nutrition, sex and age, breed is the most important factor. These researchers, as well as Bonsma (1983), concluded that a sleek coat may indicate metabolic efficiency and the ability to react better to stress.
Body condition score is an effective tool for producers who can’t weigh cattle and may even be more significant than cow weight in improving reproductive performance. There were noticeable differences in body score between and within the four breeds. The breed with the best body condition score was Braford, followed by Afrikaner, then Drakensberger and finally Charolais.
The hide represents about 7% to 8% of an animal’s liveweight, and determines adaptability by protecting the animal from its environment. The hide was measured three times by the skin fold thickness over the mid-side area, which is relatively uniform. Thickness varied markedly. Afrikaner heifers had the thickest hides and Charolais the thinnest. No significant differences were reported between the Brafords and the Drakensbergers.
Afrikaner was the least prone to ticks
The indigenous Afrikaner and Drakensberger breeds showed the strongest tick resistance, and the Charolais had the most ticks. In previous studies Spickett et al found the indigenous Nguni breed harboured noticeably fewer ticks during periods of peak tick abundance than Bonsmaras and Herefords. Frisch and O’Neill (1998) ranked the Charolais breed last for tick resistance. The study confirms the indigenous Afrikaner and Drakensberger breeds, as well as Brafords to some extent, do have an improved ability to resist ticks. This is ascribed to their thicker hides and sleeker coats, which act as tick deterrents. |fw
Accurate weather forecasts for your farm
A Norwegian-based weather website can now provide accurate, and specific weather predictions for almost every farm in the country. Greg Miles reports.
Farmers have often had to rely on weather forecasts for areas some distance from their farms, or inaccurate forecasts covering a very broad area. This could be tricky, for example when curing hay for baling and needing to know what time of the day to expect rain. This is where weather forecasting website www.yr.no excels.
Released in September 2007, www.yr.no is a joint online weather service run by the Norwegian Meteorological Institute (www.met.no) and the Norwegian Broadcasting Corporation (www.nrk.no), used by 1,3 million people a week. The English version is available at a click of a button.
Farmer’s Weekly compared forecasts for five adjacent farms and found slight differences – forecasts aren’t based on readings from the closest weather station, but from meteorological satellites. Instead of forecasts like “your region can expect a 30% chance of showers”, www.yr.no offers the user a few options.
“Overview” splits the day into three six-hour periods and gives the temperature, wind direction and expected weather for the next three days, plus the expected rainfall in millimetres. An hour-by-hour forecast is available, and a long-term forecast covers the next nine days. The weekend forecast covers the upcoming Friday, Saturday and Sunday. The site also gives the farm’s name, altitude and map coordinates, and as a bonus, a satellite photo provided by GoogleEarth.
Visit www.yr.no. |fwPositive feedback from farmers
Eben Barnard, dairy farmer near Geysdorp, North West.
“It’s extremely accurate. I used to listen to the forecast for Vryburg and Mmabatho – both 80km from me. But this website, for instance, predicted rain for the past two days, which fell within a half an hour of the predicted time, and the amount predicted was also spot on.”
Glen Olivier, professional hunter on Uxbridge farm, Eastern Cape.
“I went onto the website and it predicted 1mm of rain at 8pm, just after a Super 14 rugby match. We were braaing when it started to drizzle lightly. I checked the time and bliksem, it was 8:20pm. We measured 1mm of rain. It’s simply amazing.”
Rob Dobrowsky, Stutterheim farmer.
“It’s very useful and surprisingly accurate. Our closest forecasts on the television are for Queenstown, Bisho, East London and Umtata, but we’re between all of those. Now I can get an exact forecast for my farm.”
Biotech & food poisoning, genetic technologies and genetically modified (GM) plant varieties gave rise to an avalanche of doomsday predictions of adverse effects on humans and environment. None of these scare-mongering allegations have been substantiated after 14 years of GM crops grown on 800 million hectares, and derived foods consumed on all continents. GM-derived foods are at least as safe as conventional ones.
A recent review of food contamination and poisoning in the US identifies the main culprits as specific strains of bacteria like E. coli, Salmonella, Campylobacter, and Listeria, while mycotoxin contamination comes from certain fungal infections. Such infections may occur at any point in the food chain, from the farm to the home kitchen.
Secondary contributing factors are the more complex composition of modern processed foods, mass production, more consumption of raw products, complexity of bacterial pathogens in food animals, and inadequate sterilisation procedures.
There’s no evidence that food from GM crops are more prone to such contamination.
Modern biotechnology can reduce food risks in two major ways:
First, at farm level, Bt maize reduces earworm damage and consequent fungal infection and mycotoxins by 60% to 70%. Breeders are working on developing varieties with resistance to fungi like A. flavus (producing aflatoxin). Treatment using non-toxic strains to counter toxin producers is being tested. Novel genes for resistance could be inserted to achieve the same thing.
Second, at the monitoring level, advanced equipment now enables rapid detection of very low presences of food bacteria and mycotoxins at molecular level, serving as early warning systems.
The question is whether South Africa is geared to meet these challenges. – Wynand van der Walt ([email protected])
Source: New England Journal of Medicine, February, 2009. |fw