Knowing the signs of a cow ready to give birth is important for determining whether or not she needs assistance and for understanding the physical and physiological signs. It will also be described how a calf is normally born.
Note: Calving a cow is also called relief.
Steps
Method 1 of 2: Endocrine and Physiological Passages of Childbirth
Step 1. Step 1:
Beginning of myometrial contractions (removal of the progestogen block).
- The fetus becomes stressed as it approaches the space limits in the uterus, resulting in the anterior pituitary gland releasing ACTH (adrenal-coticotropin hormone).
-
Fetal cortisol stimulates the synthesis of three enzymes (17alpha hydroxylase, 17-20 desmolase, and aromatase) to transform progesterone into estradiol.
- Estradiol promotes myometrial (or uterine) contractions making them more active and therefore noticeable.
-
Secretory activity increases in the cervix and vagina, with the production of mucus that lubricates to facilitate the passage of the fetus.
Mucus secretion helps wash off the cervical gravidic plug
-
Fetal cortisol also leads the placenta to synthesize PGF2 alpha to help eliminate progestin blockade.
- The corpus luteum begins to withdraw, facilitating the decrease in progesterone.
- Relaxin, a glycoprotein, is produced from PGF2 alpha and stimulates softening of the connective tissue in the cervix, promoting the elasticity of the pelvic ligaments and aiding the passage of the fetus.
- The fetus rotates, so that the feet and head are towards the back of the pelvis.
- With contractions, the uterus begins to push the fetus towards the cervix, putting pressure on it.
- The pressure activates the sensitive neurons found in the cervix, which sends impulses to the spine and eventually stimulates the production of oxytocin and neurons in the hypothalamus.
- Oxytocin serves to facilitate myometrial contractions activated by estradiol and alpha PGF2.
- As the pressure on the cervix increases, oxytocin increases in turn and the contraction force of the smooth myometrial muscle peaks.
-
The fetus enters the cervical canal and the first stage is complete.
Tell if a Cow or Heifer Is About to Give Birth Step 2 Step 2. Step 2:
Expulsion of the fetus.
- Strong myometrial and abdominal contractions continue until the fetus exits the birth canal.
- The feet and head put pressure on the fetal membranes until they break, resulting in the loss of amniotic and allantoic fluid.
-
The fetus becomes hypoxic (meaning it does not receive enough oxygen) and the hypoxia pushes the fetal movements which in turn stimulate the contractions.
Tell if a Cow or Heifer Is About to Give Birth Step 3 Step 3. Step 3:
Exploding of the fetal membranes.
-
The caruncles (or chronic villi) detach from the uterine walls.
Such expulsion is thought to be possible due to the enormous vasoconstriction of the arteries in the villi
-
Further contractions, in addition to involution of the uterus, will lead to expulsion of the fetal membranes.
Method 2 of 2: Physical Signs of Childbirth
Tell if a Cow or Heifer Is About to Give Birth Step 4 Step 1. Filling
One of the first signs of relieving in cows and heifers will be filling (i.e. milk collection). It can happen from 2-3 weeks up to 24 hours before giving birth.
The breasts will begin to fill, they will be turgid and well swollen, with the nipples sticking out. Most cows will show these signs 24 hours before calving
Tell if a Cow or Heifer Is About to Give Birth Step 5 Step 2. Congested and enlarged vulva
The cow's vulva at this point will widen, swelling. More creases will form on the sides and bottom than you normally would.
Tell if a Cow or Heifer Is About to Give Birth Step 6 Step 3. Sucking of the tail
The bones of the pelvis widen (due to the relaxin hormone, described above) and the initial part of the tail sinks into them.
Tell if a Cow or Heifer Is About to Give Birth Step 7 Step 4. Discomfort and considerable effort
The first signs of calving are seen when the cow usually stops fidgeting; she may kick towards her belly due to contractions and discomfort. She will also start lying down and getting up a lot, becoming quite agitated.
Tell if a Cow or Heifer Is About to Give Birth Step 8 Step 5. Isolation
A cow or heifer will usually find a separate place to give birth, whether in a clearing or in a corner of the pasture.
Tell if a Cow or Heifer Is About to Give Birth Step 9 Step 6. Transparent discharge from the vulva
Once you notice the signs of steps 1-3, you will also see the vulvar discharge. They are a part of the cervical and vaginal secretions that help reduce friction and simplify the relieving process.
Tell if a Cow or Heifer Is About to Give Birth Step 10 Step 7. Hips retract
The cow's hips will begin to retract and the belly will look even thicker in the back than it is in the front.
Tell if a Cow or Heifer Is About to Give Birth Step 11 Step 8. Expulsion of the amniotic sac
It is a yellowish sac that hangs from the vulva and is always the first thing to appear before the calf.
Tell if a Cow or Heifer Is About to Give Birth Step 12 Step 9. The feet and head emerge from the vulva
If they point down, the calf will be in the normal position. The nose will appear soon after.
Tell if a Cow or Heifer Is About to Give Birth Step 13 Step 10. The shoulders will follow, then the trunk and finally the hips and hind legs
The calf was born! Congratulations!
Tell if a Cow or Heifer Is About to Give Birth Step 14 Step 11. A minute to an hour later, a reddish goo and sack will appear
This substance can remain in the cow for 6 to 12 hours, until the contractions have caused it to be completely expelled.
The substance constitutes the placenta and the embryonic and fetal appendages
Advice
- Always check the cow he is relieving. Look for any signs of dystocia because in that case, the faster you act, the better chance you have of saving the cow and calf.
-
The placenta can normally take 6 to 12 hours to be expelled.
In cows, the placenta can be held for 24-48 hours; some do not expel it for 10 days. These are not alarming cases, especially if the female shows no signs of discomfort or pain, as she will eventually expel her on her own
-
To complete the dilation and have the contractions, it will take 2 to 6 hours.
Heifers usually employ more than cows
- A caesarean should only be done as a last resort if the calf is too large.
- The relieving process itself takes half an hour to an hour if the calf's presentation is normal. If not (dystocia), the female will need immediate assistance.
Warnings
- Never assume that all cows and / or heifers are able to give birth very well on their own.
-
Beware of grumpy cows. Hormone levels are high at this stage and a calving cow could be dangerous. Be calm but firm when working around mothers and babies.
A PVC or pipe made of strong, non-kinking material is a good weapon to protect yourself from hot-tempered mothers
-
