Status could change after the ultrasound is done. The disadvantage of ultrasound is that accuracy is limited before 28-30 days of gestation and pregnancy status is only guaranteed at the time of diagnosis. It is possible to detect fetal heartbeat in cattle with ultrasound at approximately day 21 of pregnancy, but it is more easily detected after day 25. Pregnancy status, fetal sex, ovarian function and uterine morphology are assessed with ultrasound. However, examiners and producers should remain aware of potential negative effects associated with rectal palpation on early pregnancies and conduct the procedure meticulously and cautiously. Based on current data, it is reasonable to conclude that incidence of fetal death due to manipulation of the uterus is low and value of information gained is greater than the risk. Rectal palpation also provides estimates of embryo/fetal age and detection of ovarian structures. Changes in size, texture, location and content of the uterus occur during pregnancy and the examiner must find one of these four signs before declaring the cow pregnant. A shortage of large animal veterinarians and ultrasound technicians in some areas make scheduling difficult and creates a need for alternate approaches to pregnancy testing.ĭepending on skill of the examiner and age and size of the dam, pregnancy diagnosis through palpation is performed effectively as early as day 30 and at any time thereafter until birth. They provide static information on pregnancy status at the specific moment of diagnosis. The procedures are efficient, but require a skilled technician and specific instruments. Rectal palpation and ultrasound are the most widely used direct methods for early pregnancy diagnosis. Mounting is the principal signal of estrus behavior. Technologies are available on the market such as heat patches, paints and chalks that can visually mark females that were mounted by a bull. If utilizing the estrus detection method for pregnancy check, it is important to obtain proper training for recognizing estrus behavior. Producers may observe only a few cows returning to estrus and think that more cows are in heat than the actual number. For example, undernutrition or lactation are both common causes of cows to fail cycling in and out of estrus. Although this method is simple and does not require specialized skill or instruments, there are many factors that limit its accuracy. If a cow does not return to estrus 18 to 20 days after breeding, conception probably has occurred. Observation of estrus (period in heat) after artificial insemination or natural service is a simple and early method of pregnancy detection. It is best to identify and cull non-pregnant cows as quickly as possible after the breeding season to avoid feeding them through the rest of the year. Waiting until a cow gives birth is a common observation method of checking pregnancy on hobby ranches and other small operations, but this method is a very uneconomical and inefficient. Feeling or seeing the pregnancy are direct methods whereas, indirect methods rely on chemical markers that indicate pregnancy. There are two categories of pregnancy detection tests: direct and indirect. This article is taken from Pohler’s presentation. Various methods of pregnancy checks were discussed in a presentation given by Ky Pohler of Texas A&M AgriLife Research during the 2018 Texas A&M Beef Cattle Short Course. Some tests provide additional information such as embryo or fetal viability and fetus sex. Characteristics of an ideal pregnancy test are the ability to identify correctly pregnant animals (high sensitivity) and non-pregnant animals (high specificity) as well as being simple and inexpensive to conduct under field conditions. The first step in increasing calving percentage is to select proven herd sires and then check cows for pregnancy.
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