Therio: Bovine Infertility, Poor Performance

lec 2

The best measure of reproductive efficiency is ..

Pregnancy Rate >25%

 PR = Heat detection rate x Conception rate

Poor pregnancy rate results in ..  

• Increased age at first calving in heifers

• Increased interval from calving to first service

• Increased interval from calving to conception (Days open)

• Increased service per conception

• Early culling

Reasons for poor pregnancy rate

• Poor heat detection or failure to cycle

• Abnormal cycles

• Poor conception

Reasons for poor conception ..

• Cow factors (endometritis)

• Semen/bull (quality)

• Technician (technique, Artificial insemination timing)

Most common causes of Poor reproductive performance in heifers

• Anestrus: Congenital abnormalities,  Poor nutrition

• Poor conception rate

• Poor heat detection

How large should heifers be at breeding?

Heifers should be at 60-65% of mature weight and height at breeding

Conception rate per cycle should be __%

>65%

What is Freemartinism?

92% of females born co-twin to a male. Female fetus exposed to Anti-Mϋllerian hormone (AMH) and testosterone from the male fetus due anastomosis of placental vasculature

How does the genitalia present in a Freemartin cow?

External (may be normal, large amt of hair on the vulva)

Internal (abnormal development of tubular genitalia (paramesonephric duct) and ovaries)

What are the characterists of the internal genitalia of a Freemartin cow?

Underdeveloped cervix and uterine horns (cord like), Male accessory gland (seminal vesicles) may be present, Short vagina

How can you dx Freemartinism? -

Hx,  Transrectal palpation if adult, Vaginal depth (calves less than 30 days of age), Cytogenetics (Gold standard), 

Presenting Karyotype of Freemartinism

Most are Chimera (60XX/60XY). PCR is performed to detect “Y” antigen

What is White Heifer Disease?

AKA Segmental Aplasia

Recessive sex-linked gene of with white hair coat - common in Belgian blue & shorthorn

How does the genitalia present in White Heifer DIsease?

Segmental aplasia of the paramesonephric ducts and cervix, Normal ovaries, Variable persistent hymen (mostly in shorthorn cattle), Mucometra

Key difference in Freemartin vs White Heifer Dz

WHD: functional ovaries present

(neither condition can get pregnant)

What are causes of delayed cyclicity?

• Poor growth

• Nutritional

• Trace mineral deficiencies

• Calfhood diseases

• Parasitism

At what age should you begin Reproductive tract scoring?

12 months of age

Indicators of poor reproductive efficiency in dairy cattle

• Increased days open (interval from calving to conception)

• Increased calving interval

• Poor pregnancy rates

• High early pregnancy loss

Indicators of poor reproductive efficiency in beef cattle

• Low conception rate per cycle (>65% of pregnancies should be from the first cycle of the breeding season)

• Low pregnancy rate at the end of the season

• Increased length of the calving season

What is the optimum RTS score?

3 - 5; high RTS heifers had higher breeding season pregnancy rate, got pregnant earlier and responded better to synchronization and artificial insemination

Major causes of poor reproductive performance in adult cows

• Abnormal cycles: Cystic ovarian diseases (dairy)

• Anestrus

  • Poor conception rate

What is Cystic Ovarian Disease?

Cause: disrupted GnRH/LH secretion, unable to ovulate

Result: Follicles >17-20 mm persisting for at least 6 to 10 days in absence of corpus luteum

Incidence of Cystic Ovarian Disease

• 10 to 30% in dairy

• Higher during the first 30 days postpartum

Behavioral signs of  Cystic Ovarian Disease

anestrus (mc), nymphomania, normal cycles (rare)

Causative Factors of Cystic Ovarian Disease

• Adrenal hyperfunction

• Postpartum dz/uterine infection

• High production (> 3rd parity)

• Genetics

• High selenium levels

• Season?

Types of Ovarian cysts

Follicular (thin walled) vs Luteal (thick walled, may produce progesterone)

Tx Cystic Ovarian Disease

• Goal: make the cyst more lutealized then resume cyclicity

• Admin GnRH or hCG, followed by PGF2α (OvSynch)

• More than 50% resolve spontaneously

Prevention Cystic Ovarian Disease

Difficult (involves many factors), review all farm protocols, nutrition, comfort, transition period

False Anestrus

due to Pregnancy, or heat detection problems

True Anestrus

• Small inactive ovaries - smooth surface (postpartum in beef cattle)

• Cystic ovarian diseases

• Persistent corpus luteum

• Pyometra

Postpartum anestrus in beef cattle

presents with small inactive ovaries

Causes of ovarian inactivity

• Poor nutrition (dec BCS after calving)

• Effect of lactation (beef cattle)

• Chronic diseases, heavy parasitism

• Trace mineral deficiencies

• Negative energy balance ( dairy cows)

Cow factors of Poor conception rate

• Uterine disease (endometritis) - major cause

• Failure of ovulation

• Loss of body condition

Environmental factors of Poor conception rate

Heat stress:

• > 26°C / 78-79°F, … Temp-Heat Index THI

• Inc RR & Temp

• Decrease oocyte quality

• Increased granulosa cells degeneration and decreased steroidogenesis

• Decreased progesterone production

• Reduced embryo quality

• Effect can last over several cycles

Semen factors of Poor conception rate

• Natural mating: Bull fertility/behavior (see lecture)

• Artificial insemination: sperm quality

Human factors (AI) of Poor conception rate

• Heat detection accuracy

• Insemination timing

• Semen handling (liquid nitrogen tank management, thawing temperature, time)

• Insemination technique (site of semen deposition, cleanness)

What is Puerperal metritis?

Acute inflammation of all histological layers of the uterus, first 21 days postpartum

What is Clinical endometritis?

> 21 days postpartum, Purulent vaginal discharge, no systemic illness

What is Subclinical endometritis?

• High prevelance, esp in dairy cattle

• In cytology either:

• a) 10% polymorphonuclear cells after 34 days postpartum

• b) 5% 45 days postpartum'

Why are estrus and ovulation synchronization used ?

• Beef herds (mostly for genetic improvement)

  • Use of artificial insemination

  • Embryo transfer technology

• Dairy cattle

  • Poor heat detection is a major reason for poor pregnancy rate

  • Over 70% of dairy cows in the USA are inseminated after hormonal treatment

    • Over 80% of dairy herd use estrus/ovulation synchronization programs

What devices aid in improving heat detection?

• Pressure sensitive devices: patches, or electronic

• Activity monitors (rub off paint)

• Bulls: penile translocation, vasectomy

How do you use PGF2a/analogues to synchronize heat? 

• 1 injection + heat detection and AI

• 2 injections 11 to 14 days apart: Heat detection and AI or AI between 72 and 80 then 12 hours after heat detection

• Controlled Internal Drug Releasing Device (CIDR®): Insertion for 7 days, 1 day prior to removal administer PGF2α, heat detection and AI

(don’t need to remember the days)

What stage must a cow be in to get the greatest response to PGF2a admin?

• Days 5-16, while CL is present & before natural surge

• Larger follicle will respond quicker

Controlled Internal Drug Release dispenser : CIDR Program

• CIDR silicone elastomer contains 1.38 grams of progesterone

• Insert, then on Day 6 admin PGF2α to lyse CL

• Remove after 7 Days

  • Enough negative feedback on LH

  • Regulation of follicular waves

(don’t need to remember the days)

Ovsynch Program

• Day 0 admin GnRH: synch follicular wave & ovulation or lutenization

• Day 7 admin PGF2a: lyses CL or lutenized follicle

• Day 9 admin GnRH: induce ovulation in all cows w a mature follicle

• Timed AI 0-12h after

(don’t need to remember the days)

Double Ovsynch

Two synchs back to back!

• Pros: dec anovular cows, inc % with CL at start of 2nd synch, dec % with low progestore at 2nd synch

• Cons: complicated & costly

Study Guide Questions

In your analysis of reproductive records in a large dairy, you find that of 150 cows that should have been inseminated only 80 were seen in heat and inseminated over a period of 21 days. You perform a pregnancy diagnosis on all inseminated cows, and you find that 35 of the 80 cows inseminated are pregnant. Assuming that all cows are healthy and have cyclic, answer the following questions:

a. What is the pregnancy rate in this dairy?

b. What is the major problem in this herd?

c. How can you help the producer to improve pregnancy rate?

You are presented a 13 month-old heifer that was born co-twin to a male calf. The producer kept her as a replacement heifer because he discovered that her full sister from the previous year has a great genetic value.

a. What findings would you expect on transrectal palpation of her reproductive tracts if she is a freemartin?

b. What tests would you run to confirm a diagnosis of fremartinism?

c. Which hormones are implicated in the condition?

Regarding cystic ovarian disease in dairy cows.

a. What are the 2 types of cysts? and how do they differ in terms of endocrine activity?

b. c. List 3 predisposing factors for cystic ovarian disease in dairy cattle

c. What is the most common behavioral manifestation of cystic ovarian disease in cattle?

What is the reproductive tract scoring? What is it used for?

Endometritis is a major cause of poor conception rate. List 5 risk factors for clinical or subclinical endometritis in dairy cattle.

List 3 major mechanisms by which heat stress can negatively affect pregnancy rate in cattle.

You perform a transrectal palpation and ultrasonography of the reproductive tract on a healthy show cow that the owner wants to inseminate. Your findings are as follows: Left ovary follicle of 12 mm, Right ovary: Corpus luteum of 3.2 cm, the uterus is relaxed (i.e., LF12RCL3UN). Please fill in the blank on the following section.

The major circulating reproductive steroid in the blood of the cow is …………

She could be between day ……and day …… of the cycle. To hasten her return to estrus, she can be treated with a dose of ………. This treatment will induce ….. and the cows is expected to be in heat within ------- and ---- days. To avoid heat detection, another option would be to administer an Ovsynch program. In this case, you will administer a dose of GnRH on the first day which will cause ………., 7 days later the finding on the ovaries will be as follows………………..

Which hormones will you used to finish the Ovsynch program and when will she be insemination without heat detection?