Диагностика и мониторинг на бременността при местни кози
Diagnosis and monitoring of pregnancy in local goats
кози; бременност; диагностика; наблюдение
The primary aim of the present work was to investigate the possibilities for diagnostics and monitoring of pregnancy of local Bulgarian goats through hormonal and ultrasound methods. A total of 323 local goats with average live weight of 35-62 kg aged between 1.5 and 9 years were included in the different experiments. According to the results, the blood serum progesterone assay on post mating day 21 could be used to distinguish pregnant from nonpregnant goats with an accuracy of 86.36%. By means of two-dimensional ultrasonography for pregnancy diagnosis in local goats, enlarged uterine lumen and embryo were first detected by the 21st day of gestation, whereas all studied criteria for pregnancy were demonstrated in 100% of cases by the 49th day. The accuracy, sensitivity and specificity of ultrasonography increased statistically significantly (P<0.05) from the 35th gestational day onward using transrectal and transabdominal approach and attained highest values (>89.47) on the 56th day. The parity number did not have a substantial effect (P<0.05) on studied ultrasound parameters. The most appropriate time for determination of the number of foetuses through ultrasonography was between the 43rd and 49th days of gestation. Ultrasound monitoring of pregnancy in local goats could begin from the 21st gestation day onward by observation of the uterine lumen and the embryo. Afterwards, it continues with visualisation of heart rate, placentomes and foetus parts, and biometric data could be used for determination of gestational age of the foetus when time of mating is not known. Appropriate parameters during the first third of gestation are uterine lumen diameter (R2=0.91), crown-rump length (R2=0.94) and trunk diameter (R2=0.96). During the second and last thirds, suitable parameters are the biparietal diameter (R2=0.93), trunk diameter (R2=0.96), foetal heart size (R2=0.97) and aortic diameter (R2=0.91). The size of placentomes (R2=0.87), foetal heart rate (R2=0.75) and foetal orbit diameter (R2=0.89) are not accurate indices but together with the other parameters could be used for gestational age determination. It should be taken into consideration that other factors as number and sex of foetuses, age and feeding intensity of the dam, especially by the end of gestation, could influence the accuracy of foetal age evaluation. Pregnancy monitoring through colour Doppler and three-dimensional ultrasonography could start after the 35th day of gestation for confirmation and observation of blood flow of the foetal heart and aorta. The diagnostic value of three-dimensional ultrasonography for a normal pregnancy is similar to that of two-dimensional one.