In a series of trials among Dohne Merino on Wauldby Farm in the Eastern Cape's Stutterheim district, Greta Snyman (Grootfontein Agricultural Development Institute) and Alan Fisher (Queenstown Provincial Veterinary Laboratory) sought to establish protocols for selection for resistance against barber's pole worm (Haemonchus contortus).
This pest is a roundworm that grows up to 30mm long and sucks blood from the lining of the sheep's stomach, causing anaemia. Symptoms include swelling under the jaw (bottle jaw), weight loss and reduced wool growth and tensile strength. In lactating ewes, milk production can decline. More severe infections can prove fatal.
Female worms have red-and-white stripes, hence the common name.
Data on faecal egg counts (FEC), Famacha score (FAM) and body condition score (BCS) were collected annually on all lambs born from 2011.
Selection in the Wauldby flock was aimed at increasing resistance to H. contortus, while maintaining reproductive performance, body weight, wool weight and fibre diameter, and improving wool quality traits. Selection for the production traits was done on the basis of selection indices and BLUP of breeding values for the mentioned traits measured at 14 months of age. Selection for resistance to H. contortus was based on a selection index incorporating FEC, FAM and BCS (see panel).
The data collected over the years were used to estimate heritabilities and genetic correlations among the traits. FAM had a high genetic correlation with FEC. Fisher and Snyman found that identifying animals that required anthelminthic treatment according to FAM would ensure that only truly susceptible animals were identified and destined to be culled. Resilient as well as resistant animals would not be targeted.
Bu hikaye Farmer's Weekly dergisinin Farmer's Weekly 15 April 2022 sayısından alınmıştır.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
Already a subscriber ? Giriş Yap
Bu hikaye Farmer's Weekly dergisinin Farmer's Weekly 15 April 2022 sayısından alınmıştır.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
Already a subscriber? Giriş Yap
Understanding eye conditions in horses: causes and first aid
A horse can get a swollen eye from bumping it against a tree, shaking its head to keep flies away, or even snake venom
IPM requires a completely different mindset
You need to investigate any beneficial insects that may appear on your plants, or you can purchase them
Does parrot farming protect wild species?
Those in favour of commercial captive breeding argue that breeding parrots to sell can relieve pressure on wild populations. Researchers Neil D'Cruze and Rowan Martin review the evidence.
Bacterial and fungal diseases of garlic
Garlic can be prone to bacterial and fungal diseases, and it's important that farmers are proactive in preventing infection and practise appropriate management. Magda du Toit reports.
Responsible wastewater management: a crucial part of farming
The inadequate management of waste water is a challenge that the agriculture sector needs to deal with. Magda du Toit spoke to experts in waste and water management about a cost-effective treatment system.
Technology that can help protect South Africa's farms
Farm attacks, murders, livestock and crop theft, and other rural crimes are a growing concern in South Africa. As a result, more and more farmers are turning to advanced security technology to protect their lives, properties, and livelihoods. Sinenhlanhla Mncwango spoke to experts about the security strategies that producers can adopt to combat these threats.
The impact of theft on farms in South Africa
A high number of livestock are being stolen every year in South Africa. Insurance is expensive and farmers are battling to find solutions to the problem, says Dr Lindie von Maltitz, agricultural economics lecturer in the Faculty of Natural and Agricultural Sciences at the University of the Free State.
Staying afloat amid the cost-price squeeze
John Hudson, head of agriculture at Nedbank Commercial Banking, spoke to Glenneis Kriel about the importance of environmental and social sustainability for a prosperous agriculture sector.
Free State has no reason to mark Transport Month
Free State Agriculture (FSA) is very concerned about the extremely poor state of rural paved and gravel roads in the province and has very little, if anything, to celebrate during Transport Month, which takes place every October.
SA's food system ‘vulnerable to climate change'
The Just Transition Agenda for Food System Policymaking in SA webinar, hosted by the Institute for Economic Justice (IEJ) in October, highlighted the role that South Africa’s food system plays in contributing to climate change and how vulnerable it is to the impact thereof.
