6 October 1995

Drought could knock fertility

LOW reserves of vitamins A and E in drought-hit pastures could see flocks and herds suffering poor fertility this autumn.

These elements are essential for good conception rates, says Signets business manager, Jim Stark. "When animals were short of forage over the summer dry matter intakes were reduced and so was overall vitamin intake," he says.

Mr Stark suggests producers supplement with vitamins A and E. These can be provided in a mineral/vitamin mix or by a multi-vitamin injection. The former route is often more cost effective than spending money on blood sampling to asses the extent of the problem before taking action, he advises.

Spring-born suckled calves should either be fed a mineralised creep, or be offered about 30g a day of mineral mix sprinkled over their creep. Store and finishing cattle require 50g a day of general purpose cattle mineral/vitamin mix.

Increased cases of retained cleansings is a sign of vitamin E deficiency in cows. For autumn-calvers a high phosphorus (12%) should be given. It is also recommended all calves are given a multi-vitamin injection soon after birth.

Bulls and rams should also receive supplementation for Australian research shows sperm counts and quality decline after two months on dry pasture. Ram fertility can be assessed by vet examination of fresh semen.

Sub-fertility can be resolved by making extra ram power available during tupping. An extra 10% cover should help alleviate moderate heat stress.