The seal tuberculosis agent, Mycobacterium pinnipedii, infects domestic cattle in New Zealand: epidemiologic factors and DNA strain typing.

The fur seal (Arctocephalus forsteri), which is abundant in coastal areas of New Zealand, harbors several zoonotic pathogens, including Mycobacterium pinnipedii, a member of the Mycobacterium tuberculosis complex. We describe the microbiology and epidemiology of seven cases of M. pinnipedii infection in beef cattle (Bos primigenius) in coastal areas of New Zealand in 1991-2011. Epidemiologic factors were analyzed on six case farms and a telephone survey of 55 neighboring farms. A DNA-strain typing, using analysis of variable number tandem repeats and the direct repeats (VNTR/DR) of those isolates, was used to compare them to M. bovis isolates commonly found in New Zealand cattle and wildlife. In all cases of M. pinnipedii in cattle, only one animal in the herd was found to be infected. In six of seven cases, the lesions were in the thoracic lymph nodes, indicating a likely aerosol pathway. The lack of multiple cases within a herd suggests that cow-to-cow transmission is uncommon, if it occurs at all. There was no significant difference between case and control farms in distance to sea, herd size, herd type, or farming practice. The odds ratio for access to the beach for cattle on the Chatham Islands was significantly higher than it was for farms on the mainland coastal areas (odds ratio [OR] = 3.6, 95% CI = 1.1-11.4) Likewise, the odds ratio for acquiring tuberculosis was increased when farmers had seen seals on the property (OR =  9, 95% CI = 1.4-56.1 ). In all case farms, cattle had access to seals by beach grazing areas or waterways connecting directly with the ocean. The VNTR/DR typing of the isolates showed some variation in the M. pinnipedii isolates, with only two being identical; all isolates were easily distinguishable from M. bovis isolates.

Resynchrony of postpartum dairy cows previously treated for anestrus.

Cows that are diagnosed as anestrus (defined as >3 weeks postpartum, not detected in estrus by 1 week before commencement of seasonal breeding and without a palpable corpus luteum) have a lower probability of being inseminated, a lower conception rate to insemination and hence a lower probability of pregnancy within the breeding period. A current progesterone (P) and estradiol benzoate (EB) treatment for anestrus results in an 85% insemination rate, but only 57% of cows not conceiving to that first insemination are subsequently detected in estrus 14-28 days later. Resynchrony after an initial anestrous treatment has been used to increase the probability that cows not conceiving to first insemination will subsequently be detected in estrus. Anestrous cows (n=971) were initially treated with an intravaginal P-releasing device for 6 days and given 1 mg EB 1 day after device removal (day of EB treatment=Day 0). Cows detected in estrus between Days 0 and 3 were assigned randomly to be treated with reinsertion of a used P-releasing device for 8 days (commencing on Day 15), with 0.5 mg EB at reinsertion and again 1 day after removal (EB-RS), treatment as for EB-RS group but with substitution of 250 microg GnRH for EB at device reinsertion (GnRH-RS), or left as untreated controls (no-RS). Resynchrony treatments increased the proportion of non-pregnant cows detected in estrus from Days 14 to 28 compared to no-RS (79.1, 69.8, and 55.1% for EB-RS, GnRH-RS, and no-RS, respectively; P<0.05). Fewer cows were pregnant by Days 28 and 56 following GnRH-RS than EB-RS and no-RS. The final pregnancy rate was higher following EB-RS treatment than no-RS or GnRH-RS treatment (95.0, 88.3, and 88.6%; P<0.05). In conclusion, EB-RS enhanced reproductive performance of anestrous cows compared to no-RS.