First identification of subclinical mastitis in a lactating dairy cow in New Zealand.

Case History: A gland of a cow with a high somatic cell count (385,000 cells/mL at 116 days in milk) was enrolled in a therapeutic subclinical mastitis study following a positive pre-enrolment culture. One week later, the quarter was treated with 1 g of procaine penicillin on three occasions, 12 hours apart (Day 0 and 1). A further milk sample was obtained from the quarter on Days 6, 14, and 21 after initiation of treatment.

Increasing conception rate by addition of a second prostaglandin injection in an Ovsynch and progesterone treatment programme for dairy cows not detected in oestrus before the start of the seasonal mating period.

Aims: To assess the effect on conception rate to first service, 3- and 6-week in-calf rates, final pregnancy rate and the hazard of pregnancy, of addition of a second prostaglandin (PG) injection 24 hours after the first, in a synchrony programme combining Ovsynch and progesterone in pasture-based dairy cows that had not been detected in oestrus before the start of the seasonal mating period.

Methods: This prospective, negative-controlled study was conducted using anoestrous cows (n = 1,411) from nine spring-calving dairy herds in the Waikato region of New Zealand. Ovaries of cows not detected in oestrus were examined by transrectal ultrasonography and the presence of a corpus luteum determined.