EFFECT OF NORGESTOMET ON SERUM CALCIUM AND INORGANIC PHOSPHORUS IN PREPUBERTAL HEIFERS

Abstract

Twenty prepubertal indigenous heifers (Bos indicus), aged 18-24 months, weighing
67-90 kg were selected for induction of oestrus. Another 15 prepubertal indigenous
heifers of similar age and body weight were included as control. Each of the 20 heifers
was treated with “Crestar†injection containing 3 mg norgestomet and 5 mg oestradiol
valerate. The implant was removed on day 9 of insertion and PMSG was administered
@ 300 IU to each of the treated heifers. Following treatment all the experimental heifers
were observed closely at 6 hr intervals for onset of oestrus both by visual means as
well as by parading vasectomised bulls. Serum was separated and centrifuged
immediately at 1500 rpm for 15 minutes. Serum so obtained was stored at – 20 °C until
further analysis. Calcium level in serum was estimated by Atomic Absorption
Spectrophotometer (GBC, 932AA, Australia) after processing the samples. It could be
concluded that prepubertal indigenous heifers were induced to oestrus successfully by
application of norgestomet ear implant coupled with oestradiol valerate injection and the
serum concentrations of calcium and inorganic phosphorus could reflect the ovulatory
status of the heifers.