Approach to reproductive failure in small animals

Question 1

What clinical history do we need to gather as a starting point when dealing with reproductive failure?

Answer 1

• Timings associated with the cycle, duration and frequency of females
• Fertility of the stud dogs that you have used
• What has happened in terms of the fequency and the timing of matings
• How did the mating occur
• As well as other general medical history

Question 2

What are the categories of infertility?

Answer 2

• Misunderstanding normal biology
• Failure to show oestrus
• Abnormal oestrous cycle length
• Abnormal mating
• Male infertility
• Infertility following apparently normal mating
• Pregnancy failure

Question 3

What may cause a failure to mate?

Answer 3

• Age
• anxiety
• male behaviour
• stage of cycle
• May not be compatible (in this case AI)

Question 4

Is it necessary to run the female with the male for 7 days to ensure they mate?

Answer 4

No, its unhelpful. Other factors such as the stage of cycle etc. are more important

Question 5

Is it necessary to breed on day 10-14 of heat?

Answer 5

• No. While this may work for some dogs, its more important to breed 2 days after the LH surge - fertilisation is all about timing

Question 6

At what age is semen quality optimal?

Answer 6

2 years of age, declines from this point onwards. From 6 years, poor semen quality.

Question 7

What is a proven sire?

Answer 7

Has had pups in the last 6 months

Question 8

What are the 3 fractions of ejaculate?

Answer 8

• Pre-sperm fraction
• sperm rich fraction - the part we want
• prostatic fluid fraction = roughly 95%

Question 9

Does freezing samples change the viability?

Answer 9

It can, you should check the viability after freezing, transport and thawing.

Question 10

Is it essential to do a vaginal culture prior to mating?

Answer 10

• No.
• Difficult to prove whether bacteria causes issues with mating
• Don’t want to use antibiotics unnecessarily - just to get rid of normal flora
• Brucellosis (brucella canis) is a cause of abortion - checking for this may be beneficial
• You need a reason to culture, its not necessary in most circumstances

Question 11

How long after fertilisation does implantation occur in the uterus? Is this linked to pregnancy loss?

Answer 11

12 days, yes most pregnancy losses occur at this stage

Question 12

What are some examples of the bitches uterus being an inappropriate environement that leads to foetal losses?

Answer 12

• Infectious agents
• hormones that affect the enironment

Question 13

What is hypoluteoidism?

Answer 13

• Inadequate plasma concentrations of progesterone
• Usually, infection is more likely to cause inadequate plasma concentrations of progesterone
• Progesterone can be supplemented, but this has side effects like sustatined contractions which affects whelping and mammary development

Question 14

How does hypothyroidism affect pregnancy in bitches?

Answer 14

• Can cycle normally and have puppies - BUT puppies may have lower birth weight, higher mortality rates and the bitch may have lower uterine contractions

Question 15

Is the due date always 63 days after mating? If no, when is?

Answer 15

• No, its impossible to tell.
• In general, 65 days from the LH surge = due date
• Mating date cannot be used as a point of reference because you dont know details on how many matings, the timing of mating and accidental matings.

Question 16

What impacts the gestation length?

Answer 16

• Breed and litter size

Question 17

How can you work out a whelping date?

Answer 17

• P4
• Ultrasound - Measurments and gut movement
• Temperature drops - measure BID towards the end of pregnancy. Prior to whelping, temp will drop by 1 degree celcius but only happens in 85% of cases.
• Tocodynamometry - 4-5 days before due date

Question 18

How frequent is oestrus in cats?

Answer 18

Every 2-3 weeks

Question 19

Do acts ovulate following mating?

Answer 19

Yes, they are induced ovulators. 50% ovulate following a single mating.