Applications of CIDR Protocol in Management of Anestrus in Cattle

Anestrus and its Causes in Dairy Animals

Anestrus is functional disorder of the reproductive cycle characterized by cyclicity failure-absence of heat signs. In simple meaning when cow and buffalo does not show signs of heat (Estrus). They are termed as anestrus. It is one of the most commonly occurring reproductive problems of cattle in India affecting livestock productivity and economics to a great extent to avoid that CIDR protocol is used. Anestrus is mostly observed in Heifers and lactating dairy animals. Anestrus is multifactorial problem and its occurrence signals inadequate nutrition, hormonal imbalance, persistent CL, deficiency of trace mineral, phosphorous and fat-soluble vitamins.

Cows in negative energy balance are at a very high risk of anestrus and delayed onset of cyclicity. A body condition score (BCS) of less than 3.0 on a 1–5 scale is commonly an indicator of negative energy balance. Cows with low BCS are more likely to be anestrous and it has been reported that the influence of body condition on the duration of postpartum anestrous period is mediated through differences in LH pulse frequency. Cyclic cows with low BCS tend to have poor conception rates and higher embryonic losses.

Economic impact of Anestrus on dairy producers

Infertility due to anestrus has great economic impact on dairy farmers. Anestrus leads to economic losses through increased intercalving intervals, loss of calf, production loss and treatment expenses. There are reports in India pertaining to economic impact analysis due to anestrus. In 2011 reported estimated loss of anestrus is around Rs 193 per day in cows. As the incidence of Anestrus in India has been reported high, the above figures show high economic impact on dairy farming business at country level.

Difference between Anestrus and Repeat breeders

Repeat Breeders A Repeat breeder is generally defined as any cow or buffalo that shows the normal signs of estrus but does not conceive even after three or more services (AI). The etiology of repeat breeding appears to be multifactorial and include uterine infections and reproductive tract abnormalities, hormonal dysfunction and nutritional inadequacies, and poor breeding and health management. The causes of repeat breeding have been classified in cows in a number of ways, yet Fertilization failure and early embryonic mortality are two major causes for repeat breeding problem and external factors such as environmental stress and poor breeding management.

Anestrus

Whereas Anestrus is functional disorder of the reproductive cycle characterized by cyclicity failure-absence of heat signs. In simple meaning when cow and buffalo does not show signs of heat (Estrus). They are termed as anestrus.

Anestrus due to Persistent corpus luteum

In this type of anestrus, the follicular growth proceeds through all developmental stages and undergo ovulation and CL formation which subsequently turn into anestrus due to failure of luteal regression. This is probably due to absence of failure of estrogenic dominant follicle at the time of luteal regression. Persistent CL is mostly associated with uterine pathology such as endometritis, pyometra, fetal resorption, maceration, mummification.

Sub-Estrus / Silent estrus

Sub-estrus or silent estrus is the condition in which animal will not show behavioral signs of estrus although physiological symptoms of heat present. Silent heat is usually manifested as unobserved heat by the dairy owners. Under these conditions, follicular development and ovulation occurs normally in animals without the manifestation of overt signs of estrus. Sub estrus is common during the post pubertal period in heifers and early post–partum (30 to 120 days) in high yielding dairy cows. Progesterone secreted from regressing CL of previous cycle potentiates the action of estrogen and seems to favors the manifestation of estrus in next cycle. Thus, lack of progesterone priming results in sub–estrus.

Common trends in Anestrus treatment and management in dairy animals

Anestrus is a multifactorial problem. Hence Veterinarians has to keep rational approach based on the causes involved in development of anestrus. The case of the anestrus need to be ruled out based on factors involved like inadequate nutrition, improper body condition score (BCS), hormonal imbalance, persistent CL, deficiency of trace mineral, phosphorous and fat-soluble vitamins. If the dairy animal is non-cyclic due to hormonal causes. The hormonal treatment need to be done.

Exogenous use of Progesterone in Anestrus Management in Dairy animals

Exogenous progestins (Progesterone devices) are considered appropriate for noncyclic (anestrus) postpartum cows. CIDR inserts are approved for induction of estrus cycles in anestrus dairy animals. When exogenous progesterone is used in the synchronization protocol, a desirable follicle is produced and been shown to elicit an increase in LH pulse frequency in postpartum anestrus cows. The progesterone from the controlled internal drug release (CIDR) was sufficient to increase and maintain a progesterone concentration in blood >2 ng/ml in the absence of CL on the ovary. Blood progesterone level rises rapidly after insertion of CIDR and declined rapidly within 24 h after its removal causing ovulatory estrus.

The application of CIDR Protocol devices to be followed with suitable protocols. The inclusion of CIDR to the Ovsynch protocol considerably increased conception and pregnancy rates compared to Ovsynch protocol alone in dairy cattle. CIDR inserts to be implanted in dairy cattle cautiously using hygienic precautions.

The information on CIDR devices and its usage in management of Anestrus and sub estrus in dairy animals are discussed in detail below.

Controlled Internal Drug Release Device

What is CIDR

Controlled internal drug release (CIDR Protocol) devices are used for treatment of Anestrus and for synchronization of estrus in dairy animals. They are T-shaped devices –nylon spine molded with silicone rubber skin. The silicone coating is impregnated withprogesterone.

​CIDRs are inserted intra-vaginally using a specialized applicator. The wings of the CIDR insert have the ability to be folded together in order to insert intravaginally. Once inserted, the flexible wings return to their original T-shape position and apply pressure to the vaginal walls to hold the insert in place. The expansion of the wings retains its position; CIDRs have very high retention rates that may exceed 97%. A thin nylon tail remains exteriorized and is used for removal.

How does CIDR works in Anestrus management in dairy animals

Each CIDR insert contains the exogenous hormone progesterone. The CIDR intravaginal release insert delivers progesterone at a controlled rate in to the vagina of the treated animal. This progesterone is released by diffusion from a silicone rubber matrix encapsulated over a nylon spine which is shaped to retain the insert in the vagina. The progesterone from the CIDR insert is absorbed through vaginal mucosa resulting in to plasma progesterone levels of sufficient magnitude to suppress the release of LH and FSH from the hypothalamus for the duration of recommended treatment period. This negative feedback effect on the pituitary prevents oestrus and ovulation. CIDR induces cyclicity in anestrus animals on removal after 7^th day. It triggers pituitary gland to release GnRH leading to production of FSH and LH that helps the animal to get back on estrus. The mechanism by which non-cyclic dairy animal get back to cyclic is as below.

After placement or insertion of CIDR in dairy animals, the progesterone hormone once inserted, CIDRs provide slow-releaseadministration of progesterone, which artificially extends the luteal phase. Plasma progesterone levels rapidly increase upon insertion, and remain relatively consistent while in place. Following CIDR removal, progesterone levels decrease rapidly. Occasionally, vaginal irritation may occur and triggers pituitary gland to release GnRH. This is normal and does not impact the effectiveness of the device or the animal’s performance. Removal of CIDR insert allows LH pulse frequency to increase resulting in oestrus and ovulation of the emerging dominant follicle.

What is Ovsynch-CIDR Protocol

There are various CIDR protocols reported by several authors during field studies. Ovsynch-CIDR is the well-documented hormone treatment protocol used by veterinarians to treat anestrus cases in heifers and dairy animals. As per literatures and publications available, it is documented that after application of scientific protocol, non-cyclic heifers and dairy animals can bring back to estrus successfully. The probable conception and pregnancy rates are also significantly higher than others protocols.

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The Ovsynch-CIDR protocol is as follows:

Day 00: 1 shot of GnRH and CIDR vaginal insert with applicator

Day 07: Removal of CIDR and 1 shot of Prostaglandin F2α (PGF2α)

Day 09: 1 shot of GnRH 48 hours after PGF2α

Day 10: Inseminate 16 hours after day 9 GnRH shot

This protocol is well practiced for estrus synchronization in larger dairy farms to make profitable dairy production. The advantage of this protocol is fixed time of artificial insemination (TAI) hence there is no need of heat detection on 10^th day. In case of heifers, CIDR has to be removed on 5^th day. The other protocol remains same.

What is the benefits of Ovsynch-CIDR protocol in treatment of anestrus heifers and dairy cows.

To induce estrus cycle in dairy animal
Easier and more accurate heat detection
Fixed time of artificial insemination Higher conception and pregnancy rates
Reduced intercalving period

How to administer CIDR in dairy animals

For best results, follow these steps:

1. Wear protective gloves whenever handling the Eazi-Breed CIDR.
2. Prepare a container of clean water with disinfectant solution to wash the applicator between uses.
3. Fit the body of the insert into the applicator with the tail along the slot. The two wings will be pushed together, protruding about 1 inch above the top of the applicator.
4. Apply a generous amount of lubricant to the tip of the insert.
5. Shift the animal’s tail to one side, and clean the vulva.
6. Make sure the tail of the EAZI-BREED CIDR Cattle Insert is facing upwards.
7. Open the lips of the vulva and insert the applicator at a slight upward angle, moving forward over the pelvic bone until it meets resistance, then rotate the applicator so the tail is curling down to hide from curious penmates.
8. Dispense the insert from the applicator by depressing the plunger, then slowly withdraw the applicator body.
9. To prevent removal by curious pen mates, you may want to clip the tail of the insert so that 2.5 inches protrude from the vulva.
10. To withdraw the insert, simply give the tail a gentle but firm pull to release the insert.
11. Dispose of used inserts in a sealed, plastic container in accordance with applicable local, state and federal regulations.

Ovsynch-CIDR Protocol usage Checklist for Veterinarians:

Dr. Vijay Muley

LEAD-Technical,
Ruminants Zoetis India Limited

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