Bovine mammary glands were inoculated intracisternally with a streptomycin-resistant (SR) strain of Corynebacterium bovis to determine the number of colony-forming units (CFU) required to induce colonization and to maintain persistence of C bovis colonization throughout lactation and involution. Streptomycin resistance was used as a strain marker. Uninfected quarters in cows during midlactation were challenge exposed with successively higher numbers of SR C bovis until all quarters became colonized. Inoculum containing 790 CFU of SR C bovis established colonization in only 7 of 38 quarters. Colonization persisted in only 4 of these quarters by 23 days after inoculation. Eleven quarters were reinoculated with higher numbers of SR C bovis, and all became colonized by the time challenge-exposure inoculum contained 8 X 10(4) CFU. Colonization persisted throughout the 93-day experimental period. Somatic cell counts were significantly (P less than 0.01) higher in SR C bovis-colonized quarters after inoculation than before. Sixteen additional quarters were inoculated with a mean number of 8 X 10(4) CFU of SR C bovis 7 days before suppression of lactation. All quarters became colonized, and SR C bovis was shed during the experimental period; throughout the nonlactating and peripartum periods, high numbers of SR C bovis in pure culture were shed from 13 of 16 quarters.

A total of 301 Thoroughbred mares were investigated the characteristics of breeding in the local areas in Jeju during the period from February 2000 to July 2001. The pregnancy rate and foaling rate in 143 mares were 93.0%, 72.0%, respectively, and mean gestational length was 339.3 days in 2000. The pregnancy rate in 158 mares was 86.7% in 2001. Mature follicles were ovulated in right(46.0%), left(45.2%), and bilateral(7.8%) ovary. The incidence of multiple pregnancies in 158 mares between 15 days and 45 days after mating were 89.3%(single), 10.1%(twin), and 0.6%(triple). The incidence of EED was 13.3%.

To establish a prediction table of parturition day real-time B-mode ultrasonographic examinations were performed in 12 pregnant Shih-tzu bitches. Measurement of inner chorionic cavity diameter and fetal head diameter was performed from 15 days of gestation to parturition. These were converted retrospectively based on the day of parturition (Day 0). The data of inner chorionic cavity diameter obtained from Day -44 to Day -25 and fetal head diameter obtained from Day -25 to Day -1 were used to compile a prediction table of parturition day.

The aim of the present study was to test the efficiency of estrous induction in the premature, metestrous and anestrous bitches. The estrus was induced with prostaglandin F2 alpha, estradiol-17 beta, pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG) in the treatment A, and with PMSG and HCG in the treatment B. Day 0 was the first day of estrone injection in the treatment A and the day of PMSG injection in the treatment B. Twenty three of the twenty six bitches laparotomized under general anesthesia between 11 and 18 days after onset of behavioral estrus, whereas three bitches were not laparotomized and remained until parturition. Ovarian responses were evaluated with the total number of corpora lutea or ovulation sites. The uterine horns were flushed with phosphate-buffered saline added heat treated canine serum (10 %), the flushing media was collected into watch glass and the ova were examined under stereomicroscope. Standing estrus was observed on the day 17.7 +- 1.5 after injection of estrone in the treatment A, but ovarian responses were not detectable. Standing estrus was observed on the day 12.2 +- 0.2 after injection of PMSG in the treatment B and 14 of 17 bitches showed ovarian responses. Ova were recovered in 9 of the 14 bitches. Ovarian responses were observed in one of the three premature bitches, two of the three metestrous bitches and all of the 11 anestrous bitches. The average number of the ova collected from 9 bitchs were 12.2 +- 1.4. Three bitches in the treatment B exhibited behavioural estrus and all of them were mated with fertile male dog, resulting the pregnancy in only one bitch. The pregnant bitch gave the birth of two pups

A expressão dos genes que codificam os receptores de estrógeno (REα RNAm) e ocitocina (ROT RNAm) foram estudados no corpo lúteo de cadelas durante a gestação e parto. A técnica de PCR em tempo real foi realizada para quantificar a expressão do REα RNAm e ROT RNAm no corpo lúteo de cadelas durante o início (até 20 dias de gestação), meio (20 a 40 dias) e final da gestação (40 a 60 dias), e durante o parto (pródomos do parto). O corpo lúteo apresentou expressão do RNAm para o ROT, entretanto o RNAm para o REα não foi detectado. Houve redução na expressão do ROT RNAm no corpo lúteo a partir de 20 dias da gestação, indicando papel no mecanismo de reconhecimento gestacional em cadelas. Em conclusão, a expressão do ROT RNAm no corpo lúteo de cadelas apresentou variação ao longo do tempo de gestação, sugerindo que a resposta e sensibilidade à terapia hormonal pode variar conforme o momento da gestação e parto. Ademais, o corpo lúteo canino não expressa REα RNAm durante a gestação. | The expression of genes encoding the receptors for estrogen (ERαmRNA) and oxytocin (OTRmRNA) was studied in the corpus luteum during pregnancy and parturition in dogs. Real-time PCR was performed to quantify the levels of ERαmRNA and OTRmRNA in the corpus luteum of bitches during Early (up to 20 days of gestation), Mid (20 to 40 days) and Late Pregnancy (40 to 60 days), and Parturition (first stage of labor). The corpus luteum expressed mRNA for OTR, however ERα mRNA was not detected. There was a reduction of OTR mRNA expression in the corpus luteum from gestational Day 20 onward, which suggests an important role of OTR mRNA in the mechanism of pregnancy recognition in dogs. We concluded that the expression of OTR mRNA in canine corpus luteum vary over time, which support the idea that the sensitivity and response to hormone therapy can vary along the course of pregnancy and labor. Moreover, the canine CL lacks ERα mRNA expression during pregnancy.

A cabeça dos cães apresenta uma considerável variabilidade quanto suas dimensões, tais como comprimento, largura (diâmetro biparietal) e altura, segundo sua classificação anatômica em braquicefálicos, mesaticefálicos e dolicocefálicos. Tais aspectos arquitetônicos devem ser considerados ao tentar padronizar valores que caracterizem a gestação canina, em geral por meio de ultra-som. O objetivo deste estudo foi o de utilizar a ultra-sonografia para correlacionar as dimensões do crânio fetal e a idade gestacional com a finalidade de contribuir para o estudo comparativo do desenvolvimento intra-uterino do crânio dos cães. Examinou-se 10 cadelas da raça boxer com um aparelho portátil da marca GE®, modelo Logic á 100 MP, equipado com um transdutor convexo 5,0 MHz e outro linear de 7,5 MHz, de 2 a 3 vezes por semana a partir do 18º dia de gestação até o parto. As variáveis HC, CC e DBC foram aferidos a partir de quando foi possível distinguir a cabeça do corpo fetal, até o fim da gestação. As informações obtidas foram plotadas em gráficos de dispersão das mensurações em função do número de dias antes do parto. Concluiu-se que as variáveis estudadas são consistentes entre as gestações estudadas, apresentaram-se altamente correlacionadas entre si e com a idade gestacional e que a variável DBP é a mais tecnicamente fácil de ser aferida.