Therapeutic management of hypovitaminosis A and zinc deficiency in a lactating cow from a small dairy herd in muranga county, Kenya

Abstract

Background: Hypovitaminosis A and zinc deficiency were diagnosed in a 7-year-old Friesian cow from a small milking herd comprising of thirty Friesian cows in a zero grazing unit in Muranga County in Kenya, on Friday, November 15, 2019. The cow was weighing approximately 500 kilograms and had calved four months ago. The daily production of milk was tweny five litres. The cow had a history of sudden inappetance, reduced weight, sternal recumbency, convulsions and heavy lacrymation. Clinical examination revealed slight clouding of the cornea, and dilated pupils which did not respond to light. The menace response was almost absent but palperal and corneal reflexes were present. The cow was not apparently blind. Methods: The clinical examination of the skin revealed a fungal infection. Skin scrapings and hair from the lesions were examined for fungal species by direct microscopy in 10% KOH and lactophenol. Collected samples were inoculated on mycobiotic agar. The inoculum was incubated at 28°C for two to six weeks and examined for colony formation. Culture examination revealed Trichophyton verrucosum as the cause of dermatophytosis. Blood sample was taken from the cow into a vial containing heparin for spectrophotometric estimation of vitamin A and serum zinc concentrations. Results: Vitamin A and serum zinc concentrations were 5.12 μg/dl and 3.24 μg/L, respectively. The reference serum values for vitamin A are in the range of 15.4 to 32.3 μg/dl, while reference serum zinc levels are in the range of 6-12 μg/L for optimum physiologic functioning in dairy cattle. On the basis of history, clinical examination and significantly low serum vitamin A and zinc levels, the lactating friesian cow was diagnosed to be suffering from combined hypovitaminosis A and zinc deficiency. The dairy cow was therapeutically managed through administration of zinc sulphate orally, at a dosage rate of 1 gram per week for six weeks, administration of vitamin A at a dosage rate of 30,000 international units (IU), deep intramuscularly, once daily for seven days, and intramuscular administration of 3 mls of BelamylR, once daily for seven days. The body parts with lesions caused by T. verrucosum were treated through topical administration of zinc oxide ointment once daily for twenty one days. Following treatment of the lactating cow, significant improvement was observed in terms of disappearance of lachrymation, corneal clouding, sternal recumbency, skin lesions and convulsions. The appetite also returned to normal. All the other cows in the farm were supplemented with vitamin A and zinc. The client was also advised to include fresh napier and bermuda grass in the cattle diet, since they have been shown to contain adequate levels of beta carotene and zinc. Conclusion: In conclusion, zinc and vitamin A supplementation may be of benefit for recovery of cows from sternal recumbency and dermatophytosis.