Hogs born with diarrhea resistance make for healthier herds

Friday, April 8, 2016

Swine breeders in Switzerland are improving genetic resistance to disease, offering major reductions in weaner mortality without the aid of antibiotics

by NORMAN DUNN  

Breeding swine with genetic resistance to post-weaning diarrhea (PWD) and oedema disease has established a healthier pork production sector in Switzerland.

The national herd registry and AI organization SUISAG now tests around 800 Large White females and young boars, selected as elite breeding material, to identify genetic resistance to E. coli fimbriae18 (F18). From this stock, Swiss selectors have established male and female lines transferring complete PWD and oedema disease resistance to feeding hogs.

Systematic genotyping and selection with the Swiss Large White actually started as far back as 2006, says Dr. Henning Luther, SUISAG's director of breeding and export. The Swiss Large White sire line for terminal sires is marketed under the name Premo, and was selected over years for high feeding performance and excellent meat quality, including ideal concentration of intramuscular fat and low drip loss.

"Currently, more than 50 per cent  of all Premo boars are already homozygous resistant and there are now farms that use only semen from the resistant boars on  similarly tested Large White x Landrace sows. No veterinary treatment for PWD or oedema disease is needed in these herds," adds Dr. Luther.

Genotyping for resistance is also being carried out with other terminal crossing boar breeds used to a lesser extent in the Swiss hog production sector, including Duroc and Pietrain lines.

Danish results from research at the University of Copenhagen show that there is normally little problem in this field for piglets prior to weaning. The reason: resistance to E. coli and oedema disease is passed on with the milk from the suckling sow. In fact, Danish work is currently look into possible substances in maternal milk that may, in future, offer products for protecting older piglets against diarrhea caused by E. coli F18.  

After weaning, though, it is reckoned that 20 to 50 per cent of weaners in Europe are affected by PWD (depending on the country) and that mortality during outbreaks can quickly reach 25 per cent in affected litters. Typical PWD symptoms include watery diarrhea resulting in severe dehydration and subsequent rapid loss of bodyweight.

The heavy hog revival rolls on
Not so many decades ago, the number of Hungarian Mangalitza breeding sows in Europe was down to the last few hundred. The picture was much the same for the various traditional saddleback breeds in the United Kingdom and Germany. But, thankfully, a few enthusiasts kept such breeds in existence through the second half of the 20th century.

Now, these old heavy hog types are offering a new taste experience to the present generation of "slow-food" chefs and gourmets. This realization comes at just the right time for hog farmers looking for a niche market away from the ultra-low margins which stem from churning out lean meat from modern hybrids, no matter how efficient they undoubtedly are.

Helping them cater to this growing market for tastier hog meat are researchers at the north German Leibniz Institute for Farm Animal Biology. The Leibniz team recognized the surge of delicatessen interest in fat but flavourful pork and saw in the hardy, curly-coated Mangalitza swine the sort of meat that might attract those seeking new eating experiences.

The German breeding institute teamed up with the Herceghalom-based Research Institute for Animal Breeding and Nutrition in the Mangalitza's homeland to establish a breeding program aimed at fine-tuning the heavy breed to meet modern management requirements. Already present in the old genes, noted Prof. Klaus-Peter Brüssow from the Leibniz Institute when starting the trial some years ago, is a general robustness and good mothering ability. At the same time, Mangalitza meat proved to produce very special bacon, ham and salami products.

One problem: fertility was generally low, so selection was needed for improved feeding performance. Targeted breeding plus enhanced feeding management for the production herds aimed at stimulating fertility have resulted in improved production lines within a breeding herd now thought to be well over 60,000 head.

This institute has ended its trials, although there are now plenty of other enthusiasts in the United Kingdom and the United States running productive Mangalitza herds. Back in Hungary, the Herceghalom Research Institute continues to support a breeding program and holds so-called "Heavy Hog Conferences" focusing on development of this, and other, traditional heavy hog breeds. The events attract not only breeders and farmers worldwide, but also processors, restaurateurs and delicatessen owners.

Another supporting event also based in the Mangalitza homeland is a two-day festival spotlighting the breed and its products. The latest Mangalitza Festival was held in Budapest this February.

This heavy-hog renaissance includes the black and white saddleback swine, such as the British Saddleback (formerly Wessex) from England and the Sattelschwein in Germany. Their respective numbers have also dwindled over the years, but are now being bolstered by enthusiasts, particularly businesses applying organic management and selling the resultant meat products from farm shops or through local butchers.

The Thünen Institute of Organic Farming near Lübeck in Germany also aims to retain the high fat production of these swine so that they can survive by capturing a niche market. A first move in this direction featured a trial comparing pure Sattelschwein feeding hogs with Pietrain x Sattelschwein crosses and a Pietrain x White hybrid heavy hog type. Among the final products compared are traditional dry fermented sausages.  

The results so far reveal no great surprises. For instance, the sausages produced from the pure Sattelschwein proved unbeatable in taste panel results. The traditional breed also returned best scores for positive meat and fat parameters, including low drip loss and unsaturated fatty acid content and quality. But, as expected, the hybrids easily beat the traditional lines in daily liveweight gain terms, with an average 804 grams compared with the pure Sattelschwein's 634 grams. Back muscle area from the pure black and whites averaged only 39.2 square centimetres, with the modern hybrids developing a mean 58.2 square centimetres.  

So it's definitely taste that's the key to survival of the traditional breeds, and the ensuing niche markets. The recent German research concludes that crossing with Pietrain for the slaughter generation maybe offers the best of both worlds.

A piglet-saving solution: recording body temperature on camera
The first sign of mastitis, metritis or other postpartum problems with the suckling sow is often when feed consumption falls off and condition is just melting away. What's needed is earlier warning of a sick sow in the farrowing house, argues Danish researcher Dennis Dam Sorensen.

The solution could lie with an infrared camera taking regular temperature measurements of each sow in the farrowing house, feels this member of Aarhus University's Department of Animal Science. Recordings based on this concept, refined by Sorensen, can show 0.5 C differences in body temperature, enabling any sow health problems to be nipped in the bud and giving the type of timely warning that can save lots of piglet lives and potentially lower antibiotic use.

The infrared camera used in this work so far is a handheld Flir P660 with SC660 software installed, currently billed as one of the best tools worldwide for handheld high-quality infrared inspection systems. But the degree of accuracy needed for reliable sow temperature monitoring has meant Dennis Sorensen has had to invest many hours in researching how best to use the camera.

Through comparing the infrared results with sow temperatures taken in the "old-fashioned" way with a thermometer, he has created detailed tables of readings and actual body temperatures. The researcher has also found that the ideal spot on the body to aim for was not the shoulder, udder or neck, but instead directly at the root of the ear. The system had also to be adjusted to take into account the amount of dust and ammonia in the hog barn atmosphere, as well as any moisture on the sow's skin.

Extra fibre for more weight from less feed!
Increasing fibre content in rough-milled piglet rations has had the interesting effect of producing more growth for less feed compared with a finer-ground ration, according to Schwarzenau Agricultural Institute trials in Bavaria.

The experiment was actually aimed at investigating the animal welfare role of more "natural" feed composition compared to modern fine-ground, lower fibre rations and involved 92 piglets taken from 10 kilograms liveweight through to 34 kilograms over six weeks. Half were offered a fine ground (four-millimetre sieve) ration with 30 grams of fibre per kilogram of feed and the remainder 50 grams fibre with feed milled through a six-millimetre sieve.

Piglets on the rougher meal with more fibre each consumed around 40 grams less feed per day and, on average, gained seven grams more bodyweight daily (577 grams versus 570). Was this a sign that piglets were more comfortable with the rougher composition and higher fibre content? Hard to say. But, in the end, the performance advantage from the high fibre approach was more or less balanced out by its extra cost. The additional fibre and expensive soya oil used as energy supplement all meant feed cost was around 30 Euro cents (C$0.46) per piglet more. BP