Prevention of pregnancy in bitches with the progesterone antagonist anglepristone (alizone)

A study was carried out between April 1997 and October 1998 to determine the effect of the progesterone antagonist, Aglépristone (Alizine), for the prevention of pregnancy. 93 bitches were treated, because of mismating, with Aglépristone. The owners were then contacted 2 weeks and 6 to 12 months after treatment to gather any information on effects noted over this period. The major questions were, was pregnancy prevented and if so what side effects were observed, if any, and whether any metropathies were diagnosed. Also noted was the beginning of the next heat and, if the bitch was mated, the fertility rate. Pregnancy was seen in only one bitch. In 51 bitches minor side effects, either singularly or in combination, such as a transient itch, vaginal discharge, reduced appetite, tiredness or attachment were observed. The fertility was not influenced by the treatment and the incidence of metropathies was unchanged.     

Fenprostalene-induced abortion in bitches

A long-acting prostaglandin F(2alpha) analogue, fenprostalene, was subcutaneously administered singly at doses of 5, 10, 25, 50, 100 or 150 microg on day 25 after ovulation during pregnancy in bitches (n=4 for each dosage), and maintenance of pregnancy, changes in plasma progesterone concentration, interval between the treatment and subsequent estrus and conception rate at that estrus were studied. Abortion was associated with a decrease in the plasma progesterone concentration below about 2 ng/ml, and the abortifacient effect was dose-dependent. Administration of 50 microg or more of fenprostalene induced abortion in all dogs 3 to 13 days after the treatment. The interval between administration and subsequent estrus was markedly shorter in the aborted bitches than in the non-aborted ones (P<0.01). The conception rate at the estrus in the aborted dogs was 50%, whereas all of the bitches who had not aborted became pregnant. The results indicate that a single administration of fenprostalene could induce abortion during mid-pregnancy in bitches, and the subsequent estrus may come early with a low conception rate.     

Immunosuppression in bitches with pyometra

The function of the immune system was studied in 34 bitches affected by pyometra. The mean age of the animals was 8.1 +/- 2.8 years. Samples of peripheral blood were examined using a battery of immunological tests. Data obtained from four sets of animals, grouped according to the severity of their disease, were compared. Leucocytosis (neutrophilia and partial monocytosis) and lymphopenia were detected in 62 per cent and 35 per cent of the bitches, respectively. The increase in the number of leucocytes was higher in the severely affected bitches. Inhibition of mitogen-driven lymphocyte proliferation was the characteristic feature of the immunological profile in bitches affected by pyometra, and this corresponded with the impairment of the general state of health. Sera from bitches showing functional inhibition of lymphocytes suppressed the activity of lymphocytes isolated from normal dogs. Sera from bitches affected by pyometra also had higher levels of immunoglobulins, lysozyme and circulating immune complexes. It can be concluded that pyometra is associated with an inflammatory response, but also with a marked suppression of immune system activity.     

Effects of prostaglandin f(2alpha) on corpora lutea formation and function in mated bitches

Fifteen mated bitches were used to study the effects of prostaglandin F_2α on ovarian endocrine function during the early and midluteal phase. Five dogs were kept as controls, five were given 250 μg/kg prostaglandin F_2α twice daily between the first and fifth day of metestrus, and five were similarly treated with prostaglandin F_2α between 31 and 35 days of metestrus. Function of corpora lutea was monitored by measuring serum progesterone concentrations during the first 45 days of gestation.

Dogs treated with prostaglandin F_2α during the early luteal phase had progesterone concentrations similar to controls and pregnancies were undisturbed in both groups. A dramatic decrease in serum progesterone concentration and abortion resulted after prostaglandin F_2α administration at midpregnancy.

These results indicate that prostaglandin F_2α was not luteolytic during the early luteal phase and was therefore ineffective for preventing pregnancy at that time. However, at the dosage and frequency used in this study, prostaglandin F_2α was luteolytic and abortifacient at midgestation.

     

母犬的异常发情

受生理、营养、疾病、年龄等因素影响,母犬往往会异常发情。如不能及时发现,将会延误配种。现将母犬常见的几种异常发情的原因及防治措施介绍如下：     

Experimental toxoplasmosis in pregnant bitches.

Three Toxoplasma gondii free bitches (No. 3-5) were fed 15000 sporulated T. gondii oocysts at 56, 40 and 32 day of gestation and the outcome of the pregnancy was monitored. Two of the three dogs infected during pregnancy showed evidence of congenital infection and one aborted. Two control bitches not fed oocysts delivered eight uninfected healthy pups. This study demonstrated that T. gondii can be congenitally transmitted in dogs when bitches are infected during pregnancy.     

Plasma concentrations of folic acid, vitamin B12 and progesterone of cyclic bitches, bitches during pregnancy and induced abortion and bitches with pyometra

The aim of this study was to investigate the plasma concentrations of folic acid, vitamin B12 and progesterone at different stages of the sexual cycle and pregnancy, during induced abortion and in bitches with pyometra. Bitches (n = 97) were assigned to groups as follows: a) oestrous cycle (n = 42) b) pregnancy (n = 25) c) induction of abortion (n = 10 and d) pyometra (n = 20). Oestrous cycle stages were determined by vaginal inspection and cytology. Pregnancies were estimated by ultrasound (5.0 Mhz; linear transducer; Schimadzu) at days 15-25, 35-45 and 46-63 of pregnancy. Treatments for the induction of abortion were started between days 25 and 35 after mating (5 microg/kg cabergoline daily, Galastop; 5-10 microg/kg Alfaprostol every other day, Gabbrostim). Diagnosis of pyometra was confirmed by ultrasound and vaginoscopy. Folic acid and vitamin B12 concentrations did not differ among different stages of the oestrous cycle. The mean concentration of folic acid during early pregnancy (days 15-25) exceeded levels of later stages (days 46-63): 9.4 +/- 3.7 microg/ml and 4.7 +/- 1.8 microg/ml, respectively (p < 0.01). A positive correlation between folic acid and vitamin B12 was determined in pregnant dogs ( r = 0.925; p < 0.02). Before the induction of abortion, the concentration of folic acid was 9.6 +/- 5.2 microg/ml; during abortion it decreased to 5.0 +/- 3.2 microg/ml (p < 0.01). A significant correlation (r = 0.925; p < 0.02) between progesterone and folic acid was obtained in bitches with abortion. The mean concentration of folic acid in bitches with pyometra significantly differed from that of bitches at different stages of the oestrous cycle (p < 0.05). The mean concentration of folic acid was significantly lower in metoestrous bitches when compared to bitches with pyometra (p < 0.05). The decrease of serum concentrations of folic acid during pregnancy and induced abortion show that fetal growth and abortion caused higher consumption of folic acid. Concerning bitches did not show any deficiency symptoms, which is why it can be concluded that this decrease is physiological.