Abstract. The advent of ultrasonography over a decade ago has contributed tremendously in the field of bovine reproduction. Ultrasound imaging has shown that cattle exhibit 2 or 3 waves of follicular development during an estrous cycle. Ultrasonography allows monitoring of individual follicles as they grow and/or regress over time and patterns of follicular development can thus be determined with relative precision. Other important applications of ultrasonography in bovine reproduction includes; pregnancy diagnosis, fetal sex determination, folliculocenteses, diagnosis of abnormalities of the reproductive organs, monitoring of treatment of ovarian cysts, monitoring of postpartum genital resumption, ultrasound-guided centesis and male genital ultrasonography. Recent applications of ultrasonography in bovine reproduction includes doppler ultrasonography for genital blood flow and mammary ultrasonography. The use of ultrasonography is indispensable in most studies in which morphology (structure) and function are correlated. In this paper, the literature pertaining to the use of ultrasonography in bovine reproduction is reviewed. The applications and limitations of ultrasonography are highlighted. The non-invasive nature of ultrasonography makes it an excellent clinical and research tool in bovine reproduction.
ABSTRACT. The aim of the present study was to examine the LH response to exogenous estradiol in 4 heifers with ACTH-induced ovarian follicular cysts. During the control experiment, administration of estradiol 24 hr after PGF 2α in luteal phase heifers resulted in a LH response in all 4 heifers. The LH response was obtained between 16-20 hr after estradiol administration. The peak LH concentration (Mean ± SEM; 5.1 ± 0.8 ng/ml) during the control study was significantly different (P<0.05) from the concentration after cyst formation. None of the 4 heifers responded to estradiol after ovarian cyst formation. This result suggests that heifers with ACTH-induced ovarian follicular cysts may have a defective hypothalamio-pituitary response to exogenous estradiol similar to cows with spontaneous ovarian cysts.-KEY WORDS: heifer, luteinizing hormone, ovarian cyst.J. Vet. Med. Sci. 61(8): 979-981, 1999 While several studies have documented the hypothalamopituitary response to estradiol in cows with spontaneous ovarian cysts [3-5, 17, 23], there is a paucity of information on the response to estradiol in cattle with experimentallyinduced ovarian follicular cysts. The objective of the present study was, therefore, to characterize the feedback effect of estradiol on the hypothalamo-pituitary axis in heifers with ACTH-induced ovarian follicular cysts.Animals and treatments: Four Holstein-Friesian heifers (15-18 months old) were used for this study. The heifers were housed in tied stalls and fed hay and concentrates twice a day. Water was provided ad libitum. To characterize a control LH response, heifers with functional corpora lutea, as determined by ultrasonography and plasma progesterone concentration, were injected with 25 mg tromethamine dinoprost (prostaglandin F 2α : Pronalgon F ® ;
The aim of the present study was to follow the time related developmental changes of caprine foetuses to aid in their age determination. Certain gross external features along with body size changes were studied. Twenty five pregnant Sahel does of known gestational age managed under controlled conditions were used for the study. Absolute changes in the body weight, crown-rump length and height at withers and their relative growth changes compared to body size had similar and significant growth relationships. All the parameters showed high positive significant correlation with the foetal age and with each other with r-values ranging from 0.975 to 0.998. A chronological guide on age estimation of caprine foetuses at 28 day gestational interval, evolved from observations based on developmental horizons. The present study has provided a baseline data which could be applied for age estimation of Sahel goat foetuses. It has also indicated that, it is necessary to employ many criteria involving physiological horizons to estimate the age of a foetus age within narrow limits.
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