Participation of Opioid Peptides in Sucking‐induced Oxytocin and Prolactin Secretions in Lactating Goats

The role of opioid peptides in the secretion of oxytocin (OT) and prolactin (PRL) induced by sucking was studied in goats. Seven goats were isolated with their kids (four singletons and three twins) in individual corrals 3–4 weeks after parturition. On day 1 of the experiment, the kids were separated from the does for 7 h and were weighed before and 15 min after being reunited with their mothers to assess the amount of milk obtained by sucking. The does were blood‐sampled 10 min before and at the end of the sucking period. On day 2, a similar protocol was followed, but naloxone was given immediately after the first blood sample. On day 3, the protocol was repeated but saline vehicle was injected instead of naloxone. On day 5, the naloxone experiment was repeated as on day 2. Milk ejection was evaluated as the difference in the weight of the kids before and after sucking for 15 min, and the maternal serum levels of OT and PRL were measured by radioimmunoassay. A significant decrease in the weight gain of the kids was obtained when the mothers were treated with naloxone on day 2. Consistently, serum levels of OT and PRL induced by sucking were significantly reduced; indicating that sucking‐induced OT secretion for milk ejection in lactating goats is facilitated by opioid peptides. In a second experiment performed in the same animals 10 days later, the administration of OT, immediately after naloxone administration, prevented the decrease in the weight gain induced by naloxone, suggesting that the effect of the opioid antagonist on milk ejection in goats is a result of a reduced OT secretion. The results of this study confirm the importance of sucking‐induced OT secretion for milk ejection in lactating goats, and indicate that OT and PRL secretion are regulated by opioid peptides in this species.     

Factors associated with shortened estrous cycles after abortion in beef heifers

Forty-six crossbred Hereford heifers were allotted into five experimental groups. Fenprotalene, a prostaglandin analogue, was administered to induce abortion and (or) to regress the corpus luteum (CL) in four groups of heifers about 75 d after conception. The four groups were 1) pregnant heifers, 2) pregnant heifers with the ovary contralateral to the gravid uterine horn removed 24 h after fenprostalene injection, 3) same as Group 2 but with the ipsilateral, rather than the contralateral, ovary removed and 4) heifers with uterus removed (ovaries intact) about 35 d after conception. A fifth group of nonpregnant heifers received implants containing norgestomet from 10 to 76 d after estrus and were given fenprostalene 24 h before removal of the implant. Average length of the first estrous cycle after the fenprostalene injection was 11.2, 8.3, 9.7 and 19.1 for Groups 1, 2, 3 and 5, respectively. Estrous cycles were longer (P less than .05) in norgestomet-treated heifers. Hysterectomized heifers (Group 4) did not exhibit a second estrus by 50 d after fenprostalene treatment; otherwise, all first estrous cycles after the fenprostalene injection were either "short" (7 to 13 d) or "normal" (17 to 23 d). Twenty-two of 24 heifers that aborted had short estrous cycles and two had normal estrous cycles. Short estrous cycles occurred after abortion regardless of whether the ovary ipsilateral or contralateral to the previously gravid uterine horn ovulated. Early regression of the CL (short luteal phase) did not occur in nonpregnant heifers after long-term progestogen stimulation or after hysterectomy, but it did occur in heifers with a previously gravid uterus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vetch toxicosis in cattle grazing Vicia villosa ssp dasycarpa and V benghalensis

SUMMARY The epidemiological, clinical and pathological features of a disease syndrome in adult cattle grazing woolly-pod vetch (Vicia villosa ssp dasycarpa) or popany vetch (V benghalensis) are reported. Outbreaks of toxlcosis occurred between midwinter and midsummer in 3 dairy and 6 beef herds on the north coast of New South Wales, between 1982 and 1992. Friesian, Angus, Murray Grey, Guernsey and Hereford breeds were affected. Mean morbidity and case fatality rates in affected herds were 7% (65 of 889) and 69%, respectively. Signs of pruritic dermatitis, illthrift and death were associated with an eosinophilic granulomatous inflammation of many organs, particularly involving the renal cortex, dermis, myocardium, adrenal glands, lymph nodes and hepatic portal triads.     

History and philosophy of the medical examination of horses for purchase.

This article reviews the history of the medical evaluation of the horse for purchase and the gradual development of definitions and guidelines for performing such an examination. The philosophy of pre-purchase examinations, including potential conflicts of interest, recording methods, and procedures, is discussed. The AAEP guidelines for reporting purchase evaluations are also included.     

Osmium Recycling in Subduction Zones

Peridotite xenoliths from the Cascade arc in the United States and in the Japan arc have neodymium and osmium isotopic compositions that are consistent with addition of 5 to 15 percent of subducted material to the present-day depleted mantle. These observations suggest that osmium can be partitioned into oxidized and chlorine-rich slab-derived fluids or melts. These results place new constraints on the behavior of osmium (and possibly other platinum group elements) during subduction of oceanic crust by showing that osmium can be transported into the mantle wedge.     

Multiple viral plaques with sebaceous differentiation associated with an unclassified papillomavirus type in a cat

Abstract

CASE HISTORY AND CLINICAL FINDINGS

A 15-year-old neutered male domestic short-haired cat was presented due to multiple 0.5–2?cm-diameter crusting plaques in the left preauricular region, over the bridge of nose, and in the right periocular region. The plaques did not appear to cause discomfort.