Normal and impaired postpartum uterine function in the cow

Question 1

Define puerperium.

Answer 1

Time from parturition until the complete uterine involution and resumption of regular oestrus cycles, with normal oestrous behaviour

also known as immediate postpartum period

Average duration of the postpartum period (PP) is 45 days.

Question 2

Most critical time in uterus point of view.

Answer 2

The puerperium.

Question 3

Describe normal uterine involution.

Answer 3

Significantly longer in pluriparous (40.6 days) than primiparous (34.0 days).

Average duration of the postpartum period (PP) is 45 days.

Diameter of the previously gravid horn usually halved by 5 days and its length halved by 15 days.

Whole uterus is usually palpable per rectum by 8 - 10 days.

Restoration of the endometrium: during the first 7 - 10 days PP there is noticeable loss of fluid and tissue debris (lochia). Should be gone by 18 days PP at the latest.

Question 4

The source of infection of the uterus is from

Answer 4

the environment.

Microorganisms ascend the genital tract at parturition and during the puerperium through the relaxed perineum, vulva and dilated cervix.

NB there are always exceptions

Question 5

Main driver of uterine involution?

Answer 5

PGF2 alpha

Massive release of PGF2alpha occurs during 2 - 3 weeks postpartum.

Question 6

How does uterine contamination with bacteria after parturition affect uterine involution?

Answer 6

The inflammatory process activates the arachidonic acid cascade and large amounts of PGF2alpha are formed which is an indicator of infectious process and cellular destruction of tissue.

Question 7

When does FSH secretion resume after parturition?

Answer 7

within 5-20 days

Prior to calving the high steroid production by the placenta suppress LH and FSH synthesis and content in the anterior
pituitary gland.

Question 8

The critical factor determing when the first ovulation takes place postpartum is

Answer 8

attainment of an LH pulse frequency similar to the follicular phase of the
cycle.

LH pulse frequency in the postpartum cow is regulated by nutrition, body condition score and suckling.

Question 9

Low LH pulse frequency postpartum causes

Answer 9

the first follicle to become atretic and a second dominant follicle develops.

Question 10

Without conception - the luteal phase lasts about

Answer 10

6 days.

Question 11

Metritis can affect the following tissues: (3)

Answer 11

endometrium
myometrium
perimetrium

Pyometra is a purulent inflammation of the endometrium.

Question 12

Acute metritis usually occurs within what timeframe after calving?

Answer 12

usually during the first 20 days postpartum, is of course clinical (as opposed to subclinical).

Detectable by rectal palpation, a vaginal discharge may be present.

after d20 pp its chronic

Question 13

Chronic metritis usually occurs within what timeframe after calving?

Answer 13

after day 20 postpartum, can be either clinical or subclinical presentation.

When clinical, is detectable by rectal palpation, a vaginal discharge may be present. When subclinical, is not detectable by rectal palp.

before d20 pp its acute

Question 14

Describe metritis in cattle.

Answer 14

Is a severe inflammatory reaction of all the layers of the uterus.

Animals are usually septicemic with overt signs of illness such as feve, depression, weakness, inappetence.

Usually occurs soon after calving.

Question 15

Severe toxic metritis is often caused by what bacterium?

Answer 15

Clostridium spp.

Question 16

Describe pyometra in cattle.

Answer 16

Purulent infection of the uterus with a closed cervix.

There are few if any overt signs of illness.

Corpus luteum producing P4 contribute to pyo development.

Question 17

The presence of what predisposes to pyometra in cattle?

Answer 17

The presence of a corpus luteum which puts the uterus under the influence of progesterone and can lead to pyometra (the uterus lacks PGF2alfa which would aid in not developing pyo).

P4 also depresses phagocytic activity.

Question 18

Describe endometritis in cattle.

Answer 18

Most commonly when bacteria contaminate the uterus during calving or during the early postpartum period.

Contamination of the postpartum uterus is rather common.

Question 19

Describe synergism between bacterial species that contaminate the postpartum uterus.

Answer 19

Together, some induce abcessation.
Some cause tissue destruction.
Some circumvent host immune defence mechanisms.
Some produce collagenase.
Some produce growth factor for another bact.
Some produce exotoxins that kill leukocytes.

Question 20

How to identify a uterine infection in cattle. (5)

Answer 20

rectal palpation - most common, least sensitive & non-specific

vaginoscope

uterine fluid culture - most costly, takes time

endometrial biopsy - expensive and complex

endometrial cytology - good option, used in the mare more than in cattle

Question 21

Endometrial biopsies can be used for (2)

Answer 21

for detection of bacteria in the uterus

for assessment of clinical and subclinical status of the endometrium (histology)

Main indicator for endometritis is a diffuse cellular reaction involving the mononuclear cells (immune cells). Count the immune cells in 6 fields, calc. the average.

Question 22

Rules for biopsy collection for bacteriology: (3)

Answer 22

Hygiene (animal and collection), and instruments which allow the keeping of good hygiene.

Fixation media, which provide good conditions for both anaerobic and aerobic bacteria.

Good skills or qualifications for cultivation of samples and identification of isolates.

Question 23

Uterine effects on fertility.

Answer 23

Uterine infections are a main cause of infertility, they:
increase days “open” aka not pregnant
decrease conception rates
prolong calving intervals
increase culling rates
increase reproductive disorders like ovarian cysts
decrease milk production

Question 24

Few topic are more controversial among clinicians than treatment of uterine infections in cattle. Why?

Answer 24

Lack of precise diagnostic criteria and lack of controlled trials in which various therapeutic options have been precisely compared.

Many opinions that type of treatment has little effect on the outcome of the disease.

Question 25

Basic principle in veterinary medicine = the earlier an abnormality is diagnosed and treatment is provided, ...?

Answer 25

the faster is the animal return to a normal state of health. General principle of therapy of endometritis is to halt and reverse inflammatory changes that impair fertility (reduce the load of pathogens, enhance the process of uterine defence and repair).

Question 26

Treatment strategies for postpartum metritis and endometritis in cattle. (3)

Answer 26

Intrauterine therapy Systemic antibiotics and supportive therapy Hormone therapy ## Footnote Choosing an appropriate treatment of postpartum metritis or endometritis depends on understanding the classification scheme for the disease.

Question 27

Describe hormone therapy for uterine infections in cattle. (4)

Answer 27

PGF2alfa and it analogues Objective is to induce estrous cycles = increase in estrogen levels Effects: Stimulates uterine tone to aid in evacuating abnormal contents Increases production of mucus that contains host defence compounds Induces estrous, which induces luteolysis, reduces progesterone levels, which we know contribute to infection persisting.

Question 28

When should you not use PGF2alfa hormone therapy for uterine infections? And when should you and how often?

Answer 28

Don't use during the 1st week postpartum cause early postpartum treatment (8 – 15 days PP) seems to have lower efficacy according to studies. Instead use in cows with chronic endometritis after day 25 PP, and mostly used twice (interval of 14 d between injections or 2 consecutive days).

Question 29

Describe antibiotics for uterine infections in cattle.

Answer 29

Extensive arguments whether AB are even beneficial in case of metritis and endometritis. Main concern is residues in milk and/or bacterial resistance! + Local Intrauterine versus parenteral treatment

Question 30

Describe intrauterine AB tx of uterine infections in cattle.

Answer 30

You must consider factors that affect the efficacy of drugs inside of the uterus, e.g.: Days postpartum Uterine condition Uterine tissue absorptive capabilities Drug distribution The completely involuted uterus has better absorptive capabilities than immediate PP uterus. ## Footnote Endometritis also makes uterine uptake of the AB not very good. The AB can also locally irritate the uterus further due to not being absorbed properly.

Question 31

Describe systemic AB usage for uterine infections.

Answer 31

More advantageous than intrauterine which doesn't work that well. Provides better drug distribution to all layers of the female genital tract and ovaries whereas intrauterine is absorbed poorly by inflamed endometrium. Prevents iatrogenically induced contamination of the uterus and injury to the endometrium. Avoids interference of leukocyte function. Use penicillin (option for endometritis, postpuerperal metritis, toxic puerperal metritis) or oxytetracycline (cows suffering from less severe form metritis). Some might opt for ceftiofur, 3rd gen. cephalosporin because its broad spectrum and reaches all uterine layers leaving no residues in milk.

Question 32

Cows with metritis that have fever and systemic signs should be treated how, with what?

Answer 32

Should be treated systemically with penicillin, oxytetracycline or ceftiofur (3rd gen. cephalosporin). Cows with metritis without fever do not require antibiotic treatment and can be managed with prostaglandins (e.g. cloprostenol or dinoprost PGF2alfas). ## Footnote Prevention is better than treating!