Estrus detection is very important to enhance fertility in livestock. I am interested in learning new technologies/approaches that maximize the conception and fertility of bovine species.
Maybe the question should be modified to ask what are the affordable technologies. There are in-line technologies for dairy cattle to measure progesterone. The most useful technologies are those that measure activity, because activity increases significantly at onset of estrual activity. Again these require sensors for each cow, antennae to read the sensors, computer systems and human reviews of the output. Multiple systems are available. None of these actually detect ovulation, but ovulation is linked very strongly to standing-to-be-mounted and mounting activity, so if you know the onset of estrus, then you know when to inseminate or breed. Conception or fertility are quite different from estrus. They are more strongly linked to the energy and nutritional balance up to 100 days before the oocyte is ovulated. So be careful not to confuse these two measures. An activated oocyte may be ovulated at the right time after onset of estrus, but if it was damaged by disease, heat stress, body weight loss, etc. 80 to 120 days earlier, it may have low fertility.
Maybe the question should be modified to ask what are the affordable technologies. There are in-line technologies for dairy cattle to measure progesterone. The most useful technologies are those that measure activity, because activity increases significantly at onset of estrual activity. Again these require sensors for each cow, antennae to read the sensors, computer systems and human reviews of the output. Multiple systems are available. None of these actually detect ovulation, but ovulation is linked very strongly to standing-to-be-mounted and mounting activity, so if you know the onset of estrus, then you know when to inseminate or breed. Conception or fertility are quite different from estrus. They are more strongly linked to the energy and nutritional balance up to 100 days before the oocyte is ovulated. So be careful not to confuse these two measures. An activated oocyte may be ovulated at the right time after onset of estrus, but if it was damaged by disease, heat stress, body weight loss, etc. 80 to 120 days earlier, it may have low fertility.
Indicators that can be used to determine the optimal conditions in the body of cows for fertilization and the development of pregnancy:
The determination of the optimal fertilization period at the end of estrus in cows is based on the use of the results of studies of various types of cells of the surface epithelium from the vagina, which is the general result of hormonal influences, as well as data on the physicochemical characteristics of cervical vaginal mucus [Vasilenko TF A method for diagnosing the functional state of the ovaries in animals with an expanded vagina // Patent No. 2155016, Russian Federation].
With the passage of the postpartum period in animals without obvious complications, the level of cholesterol in the blood reaches maximum values by the time the ovulatory cycles necessary for fertilization are restored and remains within these limits in the first months of pregnancy [Vasilenko T.F. The method of determining the functional state of the ovaries in farm animals // Patent № 2211683, Russian Federation].
A method is proposed for determining the functional state of the ovaries in heifers during puberty based on a study of the total protein and albumin level in the blood and the calculation of the number of globulins [Vasilenko T.F. The method of determining the functional state of the ovaries in heifers during puberty // Patent №. 2402210, Russian Federation].
Methods were developed for diagnosing the functional state of the ovaries in heifers during puberty and in the postpartum cows on the basis of studying the morphological and functional parameters of blood (hematocrit, leukocytes, including segmented neutrophils, and the ratio of lymphocytes to neutrophils). The methods allow to more accurately characterize the conditions in the body that contribute to the formation of ovulatory cycles necessary for the fertilization of animals [Mongalev NP, Vasilenko T.F. The method of determining the functional state of the ovaries in females of farm animals // Patent №. 2348377, Russian Federation; Mongalev N.P., Vasilenko T.F. The method of determining the functional state of the ovaries in females of farm animals during puberty // Patent №. 2349287].
Hello, i guess Doppler ultrasonography of middle uterine artery can be useful in predicting the ovulation as end of estrus can lead to decrease in PI and RI (under influence of estrogen in artery ipsilateral to dominant folloicle) prior to ovulation when compared to other phases of estrous cycle.Also, this technique is useful in detecting pregnancy at 17 days after artificial insemination.
Completely agreed with Akshay regarding clinical application of dopplar ultrasonography for evaluation of blood flow parameters mainly PI and RI during estrus phase and also during other phases of estrous cycle.
Apart from this, USG could also be used in association with the synchronization protocols to detect follicular diameters and assess ovulation using repeated USG's along with endocrine investigations.
I want to participate the discussion on your good question.
I think your question contains two part, first is ovulation detection and second is estrus detection (methods)… They are releated issues because of ovulation triggered by high estrogen level in blood (via LH pick) and also estrogens in blood cause estrus behaviours in cows and other animals… So detection of estrus behaviours is an indicator that ovulation will be occur very soon… However, ovulation can not be exactly determined with estrus behaviour (you can only predict and I think this decrease success of AI)/conception rate). And if you want high conception rate with artificial insemination you have to carried out AI near ovulation or on ovulation time... Therefore it is general rule that AI should be carried out second part of estrus. However, there is a problem you can not know when estrus behaviour exactly begin without high tech technology. Because, Generally estrus behaviours begin at night…
As you know in cows ovulation generally occurs 12 hours later end of estrus behaviour or 30 hours later start of estrus behaviour. It is general but it is not rule. It may easly change according to individuals and their energy balance.
We have a function with alot of unknown… And we have to determine parameters with easy, cheap and minimum working time... Otherwise, it may be impossible to provide good conception rate in herd with economical way. I mean we can provide high conception rates with high working and high technology but it can not be countinued and not economical (I mean profitable…).
Ovulation time can be predicted with ultrasonography exam of follicle. And the best way is follicular maping of ovarium. As you know generally 8,5 mm follicule is dominant follicule and follicle with 10 mm and higher generally will be ovulated… However it is not exact. So for example, if I can, I use USG to detect a follicule higher than 10 mm when I carry out AI in cow. Also we have carried out a study about this issue, we determine exact follicular diameter at the time of AI.
As for estrus detection, there are a lot of method to determine estrus. However, it is important that when estrus starts. You can detect estrus but estrus starting time is more important to reach your aim (conception). Otherwise, you only make prediction about best AI time. It looks like to trow the dice with God ;)
Estrus detection methods determining exact time of estrus begining are generally based on increasing of activation / movement and mounting. However, as you know estrus behaviours is not limited with movement and mounting behaviours. Nevertheless mounting behaviour or standing estrus is important indicator for estrus. So, GPS systems, pedometers, video recording/face recognation systems (this is limited at the time) are generally used in free systems. Mounting detectors and vasectomised bulls with chin ball are used to detection of standing estrus. Electronic mounting detectors determine exact time of mounting also. And it is important to know start of estrus behaviours (standing estrus).
Progestrone detection in milk is also an other important indicator for estrus. 1ng and lower levels may be considered as estrus…
We can predict ovulation time nearly exact. However, it may be very costly. So we have to combine some methods to predict time of ovulation and best AI. And also we use GnRH or HCG at the time of AI to be sure ovulation… However, every technique increase cost of AI success and bill per conception. Herd owener considers its efficiency only. Therefore we have to determine an economic way for this aim in the field. Neverheless, we can imagine everything and carry out fantastic ways in our scientific trials…
by using Ultrasound scanning to detecting the follicular diameter as well as intra-uterine fluids and then you can induce ovulation using hormone (GnRH or Chorulon,HCG) if the dominant follicle present (>12mm).