Pig Feeds to Use Against Molds

Feed strategies against molds
Possible pig feeding actions to deal with the mycotoxins in feed grains that are now suspected of damaging pigs’ immune systems as well as causing problems of low feed intake and retarded growth.

Clinical signs of mycotoxicosis in pigs and other farm animals represent only the tip of the iceberg regarding pig health and performance effects due to mycotoxins, warned Professor Johanna Fink-Gremmels from the veterinary faculty at Utrecht University, Netherlands.

Veterinary problems in a 250-sow Norwegian herd have demonstrated the destructive power of toxins from mouldy feed grains. In this case the answer took the form of a dietary treatment. Other possible solutions for pig units to deal with feed contamination issues were outlined recently to an international gathering of scientists specialised in mycotoxin control.

For a variety of reasons, the meeting heard, moulds and their toxic products are affecting an increasing quantity of feed ingredients worldwide. An assessment 2 years ago that mycotoxins could be found in at least 25% of all grains harvested seems now to be an under-estimate. Climate is thought to be one of the factors responsible, along with changes in farming practices and the growing of susceptible crops.

Pig producers in particular should be wary of a possible contamination in the feed diets they use. Speakers at the 3rd World Mycotoxin Forum, which took place at the end of last year in the Netherlands, were agreed that pigs are the most sensitive of the farm animal species in this respect. Five out of the 300 or more known types of mould toxin are regarded as most relevant to agriculture; the pig is rated first on sensitivity for each of them.

That view has been reinforced by scientific advice given to the European Union’s administrators by independent food safety agency EFSA, the forum was told. Referring to major toxins from the globally important fungal genus called Fusarium, it advised that pigs were significantly more sensitive than poultry or cattle to the effects of deoxynivalenol (usually abbreviated as DON) and zearalenone (ZON). Much the same was true for other Fusarium toxins known as fumonisins, for ochratoxin A (OTA) from an Aspergillus fungus and for alkaloids from ergot.

Clinical signs of illness are observed whenever any of these exceeds a threshold level in the pig’s diet. For example, the vomiting caused by DON has given it the common name of vomitoxin, but pigswill start to refuse feed and show retarded growth once its presence goes above 5-10 parts per million. ZON was described to the forum as the classic textbook model of how oestrogen receptors work. It has oestrogenic (hormonal) effects on puberty and fertility when present at more than 1-3ppm. OTA can give rise to kidney damage with a dietary level of just 200 parts per billion. Typically a European problem from contaminated wheat or barley, at higher concentrations this ochratoxin is blamed for a so-called porcine nephropathy in which the kidneys become shrunken and discoloured as well as losing their function.

One difficulty with any discussion of clinical signs and threshold levels, however, is that both sensitivity and effect are influenced by the age or production stage of the pig. Nursery pigs will be far more sensitive than a gestating or lactating sow for the impact of a Fusarium mycotoxin on their appetite, possibly because the sows have an instinctive drive to keep eating in order to fuel the development of their unborn piglets or their milk production after farrowing. Effects can also be delayed, such as the subsequent stillbirths from sows consuming moldy feed in pregnancy or the disrupted endocrine balance in gilts around puberty due to their consumption of zearalenone at an earlier stage.

See the rest of this article: Pig Feeds

When the Pig Feed Fails

Bridging in feed silos is identified as a difficulty that has started to appear more often on US grow-finish units, interrupting the supply of pig feeds to pens.

Nebraska research in the USA has identified a particular risk to the daily weight gain of growing pigs from even quite short interruptions in the feed supply from a bulk storage bin.

A research report published in the USA suggests that pig feeds are seeing shortages that are an increasing problem on American nursery and grow-finish facilities. Referring to the shortages as out-of-feed events, it says some of them are due to the mechanical failures suffered occasionally by any system for distributing pig feeds to pens. But it also points to additional disruptions due to human error affecting a delivery into the bulk storage silo and to the age-old difficulty of materials becoming bridged or stuck inside a bin so they do not flow to the out-take conveyor as desired.

More instances of bridging are being reported, the annual Swine Report from the University of Nebraska comments, as producers continue to reduce the fineness of grind for their complete feed diets in order to improve conversion. In addition to the obvious implications for pigs’ potential growth, the absences of feed resulting from bridging and other factors are a known cause of ulcers in pigs and are suspected of having links to an increased incidence of the haemorrhagic bowel syndrome and ileitis.

But the investigators in Nebraska wanted to check particularly on the longer-term consequences for growth performance from feed breaks on a unit with nursery and grow-finish places. Their earlier work, described in the university’s 2006 Swine Report, had found indications that the impact of an out-of-feed event could be greater for the growing pig than for one in the finishing phase of production. Testing in that instance had been of a period of 20 hours without feed on a random day in each week of a 16-week trial. Virtually all of the reduction in weight gain recorded for the full trial related to the first 8 weeks.

Subsequently, the examination has been widened to cover the more likely scenario in practice, involving temporary interruptions of the pig feed supply on varying occasions in their growing and finishing stages. The out-of-feed events were again staged to occur between midday and 08:00 the next day. Starting 37 days after weaning at 14-21 days old and extending for another 16 weeks, experimental groups had their feeder closed for these 20 hours up to 3 times every 2 weeks.

Once more, it seemed that the sensitivity of the pigs to intervals without feed was age-related. A linear relationship between feeder closures and growth response was detected only in the first 8 weeks of the trial. During that period, daily gain decreased in line with the increasing number of occasions on which feed supplies had been interrupted. Afterwards, however, growth showed no link to the number of out-of-feed events. Measurements across the full duration of the trial did not establish any effect on feed conversion or within-pen variability.

A more revealing pattern appeared when the researchers looked at feed intake patterns after feed supplies had been restored. Clues in this direction had already been seen in the 2006 work. Then, pigs missing feed on a random day each week increased their intakes by 14% in the first 24 hours following restoration during the first 8 weeks of the trial. But this increase soared to 42% in the second 8-weeks period. The testing described by the 2007 Nebraska Swine Report found that in the first 8 weeks even the most affected pigs (those having 2-3 intervals without feed every 2 weeks) responded by eating just 11-18% more in the next 24 hours. The following 8 weeks saw the equivalent groups adding 22-28% to their daily feed intake.

So the take-home message must be that you cannot expect growing pigs to compensate as much as finishing-stage animals for any temporary interruption in their feed supply. Speculation offered by the Nebraska team focuses on the capacity of the pig for taking in more feed. Perhaps the younger animal’s normal appetite is close to the maximum it can eat at any one time. As it ages, on the other hand, intake comes under the influence of a variety of factors and may be increased quite strongly in the short term to compensate for a previous feed-free period.

The scale of the potential impact at growing-pig level remains to be determined, however. The team observes that its out-of-feed events were rather regular for duration and therefore were possibly less influential than a sequence varying in length. Moreover, the timing of the events through the afternoon and at night did not correspond to an accepted view of pigs’ normal eating behaviour beginning around 06:00 and peaking at 14:00. On this basis, the experimental groups may have eaten before the feed break happened so that their response to it was less than if it had occurred, say, in the morning hours.

Nevertheless, there was a clear bottom-line result from the Nebraska testing. Fail to have feed in the bin or to extract it when required, this has indicated, and you will be risking a major drop in growth. Pigs in the trial that had an uninterrupted access to feed gained approximately 840 grams weight per day over the initial 56 days, in growing from about 18kg to 65kg liveweight. Those missing 3 feeding opportunities each 2 weeks over the same period managed only about 754g/day.

They were unable to eat enough to make up for lost ground once the feed supply was resumed.

When Pig Feed Prices Rise

The prices of pig feeds rise.

Continuing the search for possible responses by pig producers internationally to the effects of rising feed prices on their production costs.

What can producers do when pig feed prices rise? One of the first actions could be to look again at the feed ingredients and materials fed to their pigs.

Be aware that the case for using feed additives becomes even stronger whenever the cost of feeds increases, says Murray Hyden at ingredients supplier Agil, in an exclusive conversation for this issue of Pig International.

For example, he says, acidifiers show major benefits in terms of optimising gut health to provide digestive conditions that approach the pig’s genetic potential, improving feed efficiency and reducing mortality. They are also important in pig feeds that have a high buffering capacity, such as those used in lactation. A key application of acidifiers is to minimise bacterial numbers in the feed, lowering the risk of pathogenic bacteria such as salmonella and escherichia entering the animal.

“Protected acidifiers with fructo-oligosaccharides are especially important to young animals that have not achieved full immunocompetence, particularly weaned piglets up to 9 weeks old or animals recovering from antibiotic therapy,” he commented when interviewed at Agil’s head office in the UK. “They have a direct impact in the animal intestine. Their effect is to optimise the gut microflora and protect mucosal linings, while providing a healthy gut environment.”

More efficient pig feeding is vitally important at a time of high feed costs, he observes. All pig rations should contain antioxidants to preserve fats and oils, maintain palatability and generally maintain feed intake. Remember, too, how feed conversion rates can be damaged by the presence of mould factors in the diet. Including mycotoxin binders can reduce the severity of mycotoxicoses or even their occurrence and thereby safeguard both swine breeding and finishing performance.

“Other additives to bear in mind are the pellet binders included in cubed or pelleted feed. They have an important role to play in controlling feed costs on the pig unit, because they reduce losses due to dust or fine particles on the farm as well as at the feedmill and during transportation. Even a 1% reduction in losses from these so-called fines is valuable. It means saving one ton of feed in every 100 tons handled. I know this is obvious, but people forget!”

No pig farm is perfect, he adds. There are always opportunities to improve. Addressing any of the points mentioned will make improvements in feed efficiency that are more valuable than ever under today’s market conditions.