Published by: SPESFEED (Pty) Ltd, PO Box 48, Rivonia, 2128. Tel: (011) 803-2050, Fax: (011) 803-8201

General News

This is the last newsletter for the year 2001. We would like to take this opportunity to thank all of our clients and associates for their support during the course of the past year and to wish them well for 2002. Following on what we did last year, we have decided to make a donation to the Avril Elizabeth Home instead of sending out Christmas cards to our clients.

You will note that this newsletter comes to you from a slightly changed SPESFEED. Following legal advice we have converted our business from a Close Corporation to a Proprietary Limited company. The reason for the change is that SPESFEED has purchased a share in Avi Products (Pty) Ltd, who are a company that make specialist bird and other companion animal diets. This involvement has necessitated some changes in the way that we will operate in future. Walter will be based in Natal, where the Avi Products factory is situated but will continue to serve his clients as he did before.

Steve Kyriazis will be joining the SPESFEED team as of December 2001. He has a BSc (Agric) from TUKS and is in the final throes of completing a MSc (Agric) in pig nutrition at the University of Natal. His initial assignment will be at Kanhym where he will be exposed to the day to day management of a production unit.

Following the review that I wrote on the new edition of Scott’s nutrition I have been inundated with requests for copies of the book. Steve Leeson has just shipped me 20 copies of "Scotts’s Nutrition of the Chicken". The cost will be the equivalent of US$ 80.00, which is what it would cost directly from the publisher, but without the additional shipping charge. We also have 20 copies of Leeson and Summers book entitled "Broiler Breeder Production", at a cost of US $60.00. Please let us know if you would like a copy. We are not keen to ship them as they tend to get damaged.

The books are selling fast so to avoid missing out please buy yours now!

Shaun Storer ran a most successful Dairy Nutrition Course for us in September, but unfortunately we had to postpone the Pig course.

Our next Poultry Nutrition course will be held on the 19, 20 and 21st of March 2002. If you are interested in attending this course, please contact us for more details.

Reuters News reports as follows: -- It has been 5 years since the Flavr Savr tomato appeared on the scene and the public began to consider genetically modified foods on a wide scale basis.

While farmers and scientists generally accept the use of GMOs, what is the current status in general? How far beyond pest-and-disease resistance is the technology, and how far will consumers be willing to push?

The European Union froze the approval of new GMO crops three years ago. Brazil nearly approved GMO soybeans, only to delay final approval once again.

Japan and South Korea’s "zero-tolerance" for StarLink corn has reduced exports of corn from the U.S. to these previously leading importers.

Yet, GMOs are remaining successful. In 2001, 24% of all U.S. corn acreage was GMO corn versus 25% last year, cotton rose to 64% from 61%, and soybeans went up to 63% from 54%. So, despite the debate, millions of farmers continue GMO plantings.

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It would appear that American environmentalists have been able to prevail upon the animal production industry to do something about phosphorus emissions from animal production enterprises. To this end a vast amount of research is currently under way, not only with regards the levels of available phosphorus in feed ingredients, the use of different phytaze enzymes, and also information regarding animal requirements for phosphorus.

In this short article I have included information presented in abstract form at both the International Animal Agriculture and Food Science and the Southern Poultry Science Meeting held this year.

When it comes to determining the Phos requirement of broilers a fair amount of work has been done. Abubabos et al. From Clemson University concluded that total dietary P can be reduced from 0.5 to 0.6% from 3 to 6 weeks of age and 0.4% for broilers aged 6 weeks and older. Yan et al. In more detailed work, showed that the non phytate Phos level of broiler diets should be 0.4, 0.3 and 0.2 % for birds aged 0-3, 3-6 and 6-9 weeks of age in order to maximise body weights and bone strength. If phytaze is offered then these values could be reduced to 0.30, 0.25 and 0.15%. Timmons et al. found that the available Phos requirement for broilers aged 21 to 42 days was 0.22%.

Adding phytaze to diets in the mill, whether as a liquid application or as a dry powder can result in some variability. Timmons et al., from the University of Maryland Eastern Shore, were able to show (by feeding different levels of phytaze on a daily basis) that %CV’s of applied phytaze of up to 103% were not detrimental on weight gain, FCR or bone strength.

The first brand of phytaze to be actively marketed was BASF’s Natuphos, which has therefore become the standard against which any new products are judged. Broz et al. compared liquid Ronozyme P (500 FYT/kg) with liquid Natuphos (500 FTU/kg) and obtained similar results in terms of body weight gain, FCR and P retention. In a second experiment, using dry phytaze, Natuphos (500 FTU/kg) was used as a control while levels 500, 750 and 1000 (FYT/kg) of Ronozyme P were used as treatments. Both Negative and positive controls we used. The results are shown in the table below:

Ward et al. were able to show that the retention of Ronozyme P after pelleting at temperatures ranging from 73 to 99 °C, was no less than 70%. They conclude that this makes the product a viable alternative to liquid phytaze addition.

Timmons et al. evaluated the phosphorus sparing effect of Allzyme® an Alltech product. They found that the level that maximised tibial ash was 6769 PTU/kg and that the phosphate sparing effect of the added enzyme was 0.04%.

In a slight deviation from the other work discussed, Klunzinger et al. from Michigan State University, evaluated the phosphorus availability of Nutridense® low-phytate maize compared to dent maize in turkey toms, and concluded that the P in the test maize can safely be formulated as 90% available.

Practical Application

The important issue for most commercial nutritionists is what does all of this mean. Firstly, it is confusing that each supplier of product measures activity by means of a different method (unit). Despite this, it would appear that all of the products have a similar efficacy.

We are currently using phytaze extensively in both layers and broiler breeders and it would appear that we should also be considering it’s use in broilers. In an ideal world, liquid application post pelleting would work best, but it would appear that the use of dry powder would still have merit.

It would certainly appear that we are using phosphorus levels in broiler diets that are higher than they need be. The findings presented here are in line with the values presented by the Dutch CVB which we reported on in an earlier newsletter.

We still do not know enough about the effect of phytaze on other nutrients, but this could probably be said for many of the enzymes that are being added to feed. I believe that there is still a lot more to know about phytaze, and that the more we know the more value it will be to us.

Feed withdrawal in Broilers

Martin Zuidhof of the University of Alberta recently completed a major research project that addressed the relationship between on-farm management and contamination of broiler carcasses at the time of slaughter.

The main objectives of this project were:

1. to see how feed withdrawal time affects carcass contamination at the time of processing
2. to see how transportation time affects gut fill and contamination
3. to see if cueing broilers to eat at the same time improves the uniformity of gut emptying and contamination

Why withdraw feed?

Everyone in the broiler industry knows that the removal of feed and water from market-aged birds is standard practice. The objective of the practice is to empty the bird’s gut enough to prevent the gut contents from spilling onto the carcass when it is processed. The feed withdrawal period includes the entire time a bird is off feed before it is processed – time in the barn, in transit, and waiting at the plant.

The generally recommended length of time off feed for broilers before processing is between 8 and 12 hours (L). Most of the birds in the flock will have had enough time to empty their gut, and the effects of the time without feed on their carcass weight will be minimal. It is generally known that too much or too little time off feed can be a problem.

The experiments

Three experiments were conducted to determine the optimal feed withdrawal time. Birds were subjected to a variety of feed withdrawal times, transport times and feed cues. The effect of these treatments on the quality of carcasses, the number of condemnations and birds removed for trimming was measured. Several suggestions are being made as a result of this study. As a result of this work, the effect of feed withdrawal time on gut clearance and gut strength has been determined.

Implications

Several implications for broiler management prior to harvest arose from these trials (we realise that many of these are common sense). They include:

1. In the last 12 h prior to feed withdrawal broilers continue to increase in body mass by approximately 60g.  The longer broilers can stay on feed, the greater the potential yield of product.
2. Weight loss drops significantly in the first four hours (0-4h) and the second four hours (4-8h) after feed withdrawal, but not significantly in the third four hours (8-12h) after feed is removed. Eight hours of feed withdrawal in the barn is adequate for clearing the contents of the gut from the digestive tract.
3. Broilers that have feed withdrawn 12 h prior to loading were over 110g lighter compared to those loaded onto the transport truck without feed withdrawal. Live weight can be increased by as much as 5% by delaying or omitting feed withdrawal (note: it is very short-sighted as a producer to increase payable weight by neglecting to practice feed withdrawal).
4. Eviscerated weights were significantly reduced for birds that were off feed for 16h.  Processing should occur before birds are off feed for 16h.
5. A significant reduction in internal contamination was observed in birds that had been off feed for 12h prior to processing. This corresponds to significant decreases in intestine weight during the same time period. Feed withdrawal of 12 hours is adequate to reduce contamination and prevent carcass shrink.
6. Males and females respond to feed withdrawal and transportation times similarly. Male and female chickens do not need to be handled differently prior to slaughter.
7. Birds that are kept in the barn with access to water had reduced shrinkage. To prevent shrink, allow access to water as long as possible prior to processing.
8. Birds that are loaded without a feed withdrawal period in the barn (even after 8 or 12 hours on the transport truck) have higher levels of contamination and condemnation. At least four (4) hours of feed withdrawal time IN THE BARN is recommended.
9. Feeding cues affect broiler behaviour. Longer cue lengths resulted in more birds observed eating together. Broilers can be encouraged to eat simultaneously by using a feeding cue.
10. An unexpected gain in body weight was observed in the first hour of a feeding cue. This indicates that broilers replace feed intake with water intake very early after feed is withdrawn. Broilers should be allowed access to water to maintain body weights after feed withdrawal.
11. A two-hour feeding cue resulted in a decrease in the contents of the ileum (second ‘half’ of the small intestine). If ileum contents are a source of contamination a two-hour feeding cue may help to reduce contamination.
12. Feeding cues may increase the number of scratches observed at the time of processing. Contamination was lowest for birds that were not subjected to a feed cue. Feed cues are not a sure-fire way to improve carcass quality.
13. We did not determine a difference in gut strength related to feed withdrawal.

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10 Tips for controlling respiratory disease in pigs

Pork producers need to practice good management to prevent respiratory disease from hitting their pigs. Here are 10 tips to help control respiratory disease in all ages of pigs from Brad Thacker, DVM, of Iowa State University:

1. Give all your pigs an effective environmental temperature. Air temperature, air velocity, floor contact, radiant temperature, moisture and zone heating all play into effective environmental temperature.
2. Control the level of various gases. Producers should be concerned with humidity, oxygen, ammonia, carbon dioxide, carbon monoxide and hydrogen sulphide. Be aware of the "20-foot rule," meaning that wherever you are in a room, an inlet is within 20 feet.
3. Practice proper stocking density. Rates should be based on space requirements as pigs exit the production phase.
4. All-in, all-out production should be segregated by room, building or site. Segregation should depend on diseases. For example, viral diseases often require site separation.  This also means facilities should be disinfected between batches.
5. Feed and water should be readily available
6. Herd size influences patterns of disease spread within a herd. The larger the herd, the less room for error.
7. Cut down transmission from sows to pigs by reducing weaning ages, stabilise the immune status of the breeding herd or eliminate disease.
8. Properly store vaccines.
9. Have a biosecurity plan for inside and outside the barn.
10. Perform diagnostic testing to determine which disease is affecting your herd in order to correctly treat your pigs.

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Somatotropin (Reporcin) : Does it pay?

Introduction: Modern pigs grow fast with a leaner body composition than ever before, reflecting the producer’s response to consumer concerns about dietary animal fat. New tools have become available called repartitioning agents that produce even leaner pigs with improved efficiencies of gain. The most dramatic effects on growth performance via repartitioning agents have been seen with porcine somatotropin (Reporcin). Somatotropin is a naturally occurring peptide hormone, which has been manufactured commercially since the 1980s via recombinant DNA technology. Somatotropin is not orally active and must therefore must be administered as an injection or implant.

Somatotropin acts directly on adipose tissue by primarily decreasing the uptake of glucose into the fat cell and indirectly on muscle via its stimulation of insulin-like growth factor-I (Etherton & Bauman, 1998). The summary of effects is shown in the table below:

On lactating sows a 22% increase in milk yield was measured. The sows were however challenged due to a severe reduction in energy balance, accentuated by a 28% reduction in feed intake 

Effects of Porcine Somatotroping on Growth and Performance (100 – 150 ug/kg data from Campbell et al. (1991), Johnston et al. (1993), Evock et al. (1988), Boyd et al. (1991)

Local Trials: Since the local launch of Reporcin in May 2001 a number of farm trials were conducted. The performance results are shown in the table below:

Reporcin effects on Performance Parameters in local trials (% change from the control)