Case Study No. 1 A breeding stock company called to discuss a customer concern. This producer owned a 1,000-sow, single-site, farrow-to-finish farm, built in the 1970s. Finishing pig flow was continuous.

This customer had received complaints from the packer about excess trim from the loin area.

Pigs had an above normal percentage of broken backs and trim loss due to fractures. We considered genetics, spinal abscesses and nutrition.

This farm had a common genetic source with no reports of this nature. The plant had no problems with any of the finished hogs except the fractures.

We also reviewed the entire nutritional program from nursery through finishing. The supplier was well known for good quality control. The mill that manufactured the diets appeared to be doing a good job of processing and putting together a well-mixed ration.

As it turned out, the mill's formulation was in error. The calcium-to-phosphorus ratio in these finishing diets was inverted. The phosphorus level was greater than the calcium. The ratio of calcium to phosphorus and their levels in the diet are both keys to good bone growth.

The diets were corrected and the number of fractures at the plant returned to normal in less than 30 days.

Using a major feed supplier is not enough for quality control. Diet programs, from formulation to feed delivery system, need to be reviewed at least twice per year.

Case Study No. 2 We were called to a 120-sow, farrow-to-finish operation to observe growing pigs. The producer was concerned about the hair and skin condition of pigs in several groups.

Some 2% of the pigs showed thickened skin to the point of scaling off. Possible concerns included greasy pig disease, mange infestation and parakeratosis.

These pigs were much older than typical greasy pig disease cases (less than five weeks of age). The lesions were not particularly irritated, nor itchy as seen with a mange infestation.

When we looked at the diets for growing and finishing hogs, the farm was using a vitamin and trace mineral premix labeled for most domestic animals.

Parakeratosis is a thickening of the skin in pigs linked to zinc deficiency. Farm diets were extremely low for all trace minerals, including zinc.

Case Study No. 3 This 60-sow, farrow-to-feeder farm housed gestating sows outside. Farrowing was confined. Twenty sows were farrowed per group, averaging 180-200 pigs weaned.

Sudden nursery deaths occurred 5-10 days postweaning. Death loss ranged from 4-10 pigs per group. Postmortem lesions consisted of fibrin in the chest cavity, a "chicken fat clot" around the heart and hemorrhages.

These lesions are typical for mulberry heart disease, seen in rapidly growing nursery pigs. The history is always sudden death with no signs of disease. Mulberry heart disease can be a vitamin E and/or selenium deficient condition or a vitamin E and/or selenium responsive disease.

Deficient diets have inadequate levels for the size of pig being fed. In responsive syndromes, the levels in the diets may be adequate for the nutrient in question but additional nutrients will cause a response.

There is a legal maximum limit for selenium in swine diets; there are suggested levels for vitamin E.

This farm was at the maximum allowable level for selenium and within acceptable limits for vitamin E. All pigs were injected at weaning with vitamin E. Mortality stopped immediately.

Case Study No. 4 This unit was a 200-sow, farrow-to-finish farm on one site. The sows were in crated gestation and the facilities were conventional. The nurseries were deck flooring with fiberglass slats. Sows were farrowed and weaned weekly. The piglets were weaned at 18 days of age.

At about four days postweaning, the piglets developed severe diarrhea that persisted until about day 10. After this scour some piglets fell behind. Mortality rates ranged from 3% to 10%.

Bacteriological cultures showed a pure culture of a beta hemolytic E. coli.

Purge medications in the water were used initially to control the diarrhea. Zinc oxide was added to the first two starter diets to help control the diarrhea. The diarrhea diminished greatly and the purge medication program was discontinued.

Mortality in the nursery now ranges between 0.5% and 3%. It is important to remember that these diets were not deficient in zinc but the hemolytic E. coli responded to this treatment.