SYNCHRONIZATION OF OESTRUS IN COWS USING INTRAVAGINAL SILASTIC COILS CONTAINING PROGESTERONE

Calving rate of cows following insemination after a 12-day treatment with silastic coils impregnated with progesterone.

Farm trials were conducted to determine if the calving rate was different for control cows inseminated with frozen semen at estrus in comparison to cows treated with progesterone for 12 days and bred at the ensuing estrus. Intravaginal silastic coils impregnated with progesterone were used and an injection of 5 mg estradiol benzoate and 50 mg progesterone in corn oil was given at the time of in...

Control of estrus and progesterone levels in heifers given intravaginal progesterone coils and injections of progesterone and estrogen.

Fifty-three mature Hereford-cross heifers, which were between day 0 and 3 of the estrous cycle, each had silastic coils containing 2.1 g progesterone inserted into the vagina where they remained for 12 days. Animals were assigned to treatment groups and were injected with (1) 5 mg estradiol benzoate, (2) as (1) + 50 mg progesterone or (3) as (1) + 200 mg progesterone at the time of insertion of...

Synchronisation of Oestrus in Dairy Cows Using Progesterone Administered by "controlled Internal Drug Release" (cidr) Devices

The proportions of cows showing oestrus during the first 5 days were 22%, 78% and 87X, and by 25 days were 85%, 92% and 98% for groups 1, 2 and 3 respectively. In group 3, 83% of animals had exhibited oestrus and 49% subsequently conceived to A.I. at the fixed time of 63h. Pregnancy rates after 25 days of mating as determined by rectal palpation were 46%, 62% and 64% for groups 1, 2 and 3 respe...

Comparison of two intravaginal progesterone releasing devices in lactating dairy cows: blood progesterone profile and field

Evaluation of oestrus observation and conception rates in suckling beef cows using whole milk progesterone concentration.

A 2-sample regime was used to measure whole milk progesterone concentration on the day of oestrus and insemination (Day 0) and 6 days later (Day 6) in a sample of 50 primiparous and 100 multiparous suckling beef cows. Exposure to teaser bulls and observation by cattlemen identified the occurrence of oestrus. Three sets of criteria used to define ovulatory oestrus were compared: a) milk progeste...