Lecture 17 - 18

What signs can you use to calculate when parturition may occur in mares

Gestation = 344 days, with a range of 315-388 days

From about 2 weeks see relaxation of pelvic ligaments, and 1-2 days away from parturition their milk Ca increases (>200ppm), pH decreases (<6.4)nand K+ is greater than Na+

Form about 20-30 mins their activity is seen to increases

What signs can you use to calculate when parturition may occur in cows and small ruminants

Gestation = 270-290 days

If their pelvic ligaments drop/soften then they are likely to calve in next 24hrs

Closer to hours before parturition, they tend to separate themselves from the herd

What signs can you use to calculate when parturition may occur in pigs

Oedematius vulva a week before, or nesting behaviour 24 hr before or milk spurts around 8 hours before parturition

What behavioral signs do bitches show in preparation for whelping?

Nesting behaviors around 1 week before hand, Rectal temp drops 8 to 24 hours as a result of progesterone dropping rapidly,

How many stages of parturition are there

There are three stages of parturition: the first stage involves myometrial contractions ; the second stage is the delivery of the offspring; and the third stage is the expulsion of the placenta.

What marks stage I of parturition

Begins with initial labour and ends when the foetus enters the birth canal. Once the foetus enters the cervical canal the first stage of parturition is complete

What events happen during stage I of parturition

1. Cervical dilation and repositioning of the foetus for birth

   • Symptoms include restlessness, loss of appetite, and frequent urination.

   • Foetus typically arranges with front feet and head posteriorly in cows, mares and ewes

2. Uterine contractions and vaginal relaxation

What is the fergusons reflex

Foetus stimulates cervix nerve endings → feedbacks to hypothalamus → posterior pituitary gland releases oxytocin

How long might stage I last in the cow, mare or dog and what clinical signs might you see in this stage

Can last 1-4 hours in mares → end is marked by foetal membranes

• Behaviour includes nervous, uncomfortable, restlessness, urination, sweating, defaecation, colicky

Can last 2-6 hours in cows (longer in heifers sometimes)

• Behaviour includes kicking at belly, restlessness, urination, separation from herd

Can last 6-12 hours in dogs

• Behaviour includes nesting, restlessness, anxiety, pnting, pacing, shivering, anorexia and vomiting

During which stage of parturition does the expulsion of the foetus occur?

Stage II.

How long does stage II last per animal 

Mares = rapid delivery once chorioallantois ruptures → 5-30 minutes

Cows → 30-60 minutes

Sheep → 30 mins to 2 hours

Pigs → 3-5 hours

Dogs → 4-6 hours but can be up to 24 hours

Kittens → 4-42 hours

What consideration in stage II must you have for mares

If it takes >60mins for delivery then the foetus will die

What consideration in stage II must you have for sheep

Should always check for another lamb and should start to intervene if it lasts more than 1 hour

What consideration in stage II must you have for dogs

• Expulsion of first pup can last up to 4 hours

• Usually 30 minutes to 2 hours between pups (breaks in between)

• Note: dark green pigment of paraplacental zone

• Check HR of foetus

  • >220 bpm = no stress

  • <180 bpm = severe stress = intervention

What are common causes of dystocia

• Excessive size of the foetus

• Failure of proper foetal rotation

• Multiple births in monotocous species

• Deformed fetus

• Failure of the cervix to dilate

What happens during Stage III of parturition?

Expulsion of foetal membranes.

What hormone assists in softening the birth canal during stage II of parturition?

Relaxin.

Define altricial neonates.

Neonates that are helpless at birth and often immobile.

Define precocial neonates

Neonates that are relatively mature and mobile at birth, able to see, hear, and walk shortly after.