Page 142 - Small Animal Clinical Nutrition 5th Edition

Minerals and Vitamins 143

ated. Heavy metal toxicity screens of affected kittens were unremarkable with the exception of high-hepatic zinc level in one kitten
and a single low-hepatic iron value. Serum copper concentrations for queens were normal, but hepatic copper values were not deter-
VetBooks.ir mined because queens were in active reproduction. In one- to two-week-old affected kittens, hepatic copper concentrations ranged

from 26.6 to 35.7 mg/kg and serum copper values from 0.3 to 0.4 mg/kg, which were deemed borderline low based on literature
values.

Assess the Food and Feeding Method
A commercial dry cat food that had passed an AAFCO feeding trial for feline growth and maintenance had been fed for approx-
imately eight months to cats in this colony before any abnormalities were noted. The food was plant-based; the first four ingredi-
ents were corn, corn gluten meal, soybean meal and poultry by-product meal. In addition to containing typical vitamin and miner-
al supplements, the food also included copper oxide as a copper source and iron oxide as a colorant.
Analysis of the food disclosed no deficiencies when compared with recommended levels established for growing kittens.
However, high levels of zinc and iron were noted in the food. High levels of dietary phytates, which can reduce mineral absorption,
were expected to be in the food because of the plant ingredients it contained.

Feeding Plan
A dietary copper deficiency was considered the most likely cause of the reproductive failure noted in these queens. Although food
analysis revealed that dietary copper levels were more than adequate, the copper oxide used in the food is a completely unavailable
copper source for animals. Additionally, factors that impair copper absorption by chelation (phytates in plants) or transport compe-
tition (zinc and iron) were found in high concentrations in the food and would further impair absorption of available copper.
The cat food was supplemented with 15 mg/kg copper from an available source (i.e., copper sulfate).
Reassessment
After the food was supplemented with copper sulfate, the conception rate increased to 80% of breedings and in utero fetal death
rates decreased to 12.5%. Food intake increased to expected levels. Three months after feeding the supplemented food, coat pig-
mentation abnormalities and limb and tail deformities again became evident in newborn kittens. Serum samples were again col-
lected from pregnant queens for copper analysis. Copper values were low in four of nine queens, indicating continuing copper defi-
ciency. An additional 10 mg/kg of dietary copper as copper sulfate were added for a total of 25 mg/kg supplemental copper. No
abnormal kittens were born during the next five months.
Some less severe clinical signs of copper deficiency in kittens not consuming copper-supplemented food (i.e., queen’s milk only)
were reversible. Pigmentation and coat texture returned to normal and improved carpal flexion was observed with skeletal matura-
tion.

Bibliography
Morris JG, Rogers QR. Copper oxide is an ineffective source of copper in queen diets. In: Proceedings. Pet Food Forum, Chicago,
IL, 1995: 107-108.

CASE 6-4

Sudden Death in a Chihuahua
Patient Assessment
A three-year-old female Chihuahua was found dead one hour after being given 1.5 ml of a vitamin E preparation by intramuscu-
lar injection. The owner routinely administered the vitamin preparation twice yearly to all dogs of breeding age in his kennel. One
week earlier, a similar incident occurred with a two-year-old female Yorkshire terrier.The owner had purchased the vitamin E prod-
uct from the same veterinarian for several years. The Chihuahua and the vitamin E preparation were delivered to a diagnostic lab-
oratory for examination.
At necropsy, the lungs were wet, glistening and mottled pink. White foam was found in the trachea and bronchi. All other inter-
nal organs appeared normal. Histopathologic examination of the lungs showed congested capillaries, perivascular edema and abun-
dant proteinaceous fluid in the alveolar lumina. Liver and kidney specimens from the dog contained 12.9 and 12.1 mg selenium/kg,
respectively (normal values <3 mg/kg).

Assess the Food and Feeding Method
No food was available for evaluation. When contacted, the veterinarian suggested that the bottle of vitamin preparation might also