A simple and reliable aid to detection of oestrus in cattle would help to improve reproductive efficiency particularly where AI or embryo transfer is being used. A marking web, devised by Mr P M P Lumbar, was reported (Farmers Weekly, p40, 10 June 1988) to perform this function satisfactorily.

The marking web device is constructed simply from a piece of calico (8.5 cm x 8.0 cm) and a 8.5 cm x 2.5 cm strip of red household tape covered by a layer of black mastic stuck across the calico (Figure 1). The device is fixed to the sacral region of the heifer or cow using a suitable adhesive. Some of the devices were supplied by Mr Lumbar and the remainder were made by us. Pressure from the chest of the animal mounting peels the adhesive mastic from the underlying tape.

The marking web devices (MWD) were evaluated using two groups of maiden Hereford x British Friesian heifers. These heifers were 15 to 18 mo. old, they had a live weight of 421 kg and were in body condition score 2.4 units on average. Group I heifers (n=134) were housed in straw-bedded pens at a stocking rate of 4-5 m2 per head and fed on cut grass ad libitum supplemented with minerals and vitamins. Group II heifers (n=22) were set stocked on pasture at 6 heifers per ha.