Signs of Pregnancy in a Cow
There are several different methods by which it can be determined whether or not a cow or a heifer is pregnant. Verifying pregnancy in a cow allows for proper veterinary care to be prescribed. Cows have special requirements for nutrition and care during pregnancy. There are five reliable methods for detecting an early pregnancy in cows. These are rectal palpation, pregnancy associated protein, examination by ultrasound, hormone measurements and not returning to oestrus.
Rectal Palpation
Rectal palpation offers an immediate diagnostic result. Accuracy can reach as high as 95 percent, but depends on the practitioner's experience. Rectal palpation will allow a diagnosis at between one and three months of pregnancy. Symptoms experienced during this procedure include a corpus luteum that is palpable on the ovary, a decrease in the tone of the pregnant uterine horn and an asymmetry between the uterine horns. During the later months of the pregnancy, the foetus may also be palpable.
Pregnancy Associated Protein
Early Conception Factor (ECF) involves the test of glycoprotein associated with pregnancy being detected in a blood sample. Within 48 hours of conception, this test is capable of determining pregnancy. This method of determining pregnancy in a cow is often used for indicating conception early on in the pregnancy.
Examination by Ultrasound
Ultrasound is capable of being 99 percent accurate, which enables problems relating to fertility to be identified and dealt with quickly. The speed of the ultrasound approaches that of the rectal palpation, but ultrasound delivers more information regarding the pregnancy than rectal palpation is capable of.
Hormone Measurements
A functional corpus luteum will secrete progesterone between 18 and 24 days following insemination, and this is an excellent indicator of pregnancy early on. The hormone can be assayed either by way of milk or plasma. The optimal time for this procedure is 24 days following the act of insemination. This procedure can be up to 93.1 percent accurate, but is not as accurate in determining nonpregnancy as pregnancy.
Nonreturn to Oestrus
Oestrus signs are typically observed at three weeks following insemination or service. If these signs are not observed, it is generally assumed that the cow is pregnant. Not all of these cows may actually be pregnant, however, because as many as seven percent of cows that are pregnant will still show some signs of oestrus during their pregnancy.
Tags: following insemination, corpus luteum, days following, days following insemination, determining pregnancy, early pregnancy
