There are some key things to note when managing a bred cow herd through calving. Management practices can be measured using the GOLD management indicators.
Growth- can be calculated as weaning weight as a percentage of dams weight or weight of calf weaned per weight of cow exposed
Open- indicates fertility level of herd
Length- of the calving season measured by number of days between first and last calf being born
Death Loss- number of calf deaths from birth to weaning, goal is under 4%
Calving Management
The main measurement of a successful calving season is the percentage of calf crop.
% calf crop= No. calves weaned X100
No. of females exposed
The calf crop is a way to measure fertility, mothering ability and calf survival on your ranch. This can be directly correlated to effects on production costs and returns. The two most crucial times where proper management and genetics will have the largest impact on the calf crop percentage is during peri-partum (around calving) and at breeding.
It is important to understand the physiology of parturition to be able to properly and promptly assist cattle that are in need. Parturition is defined as the act of giving birth. Parturition has an average fatality rate of 3-5% at or shortly after birth.
1. Relaxation or Preparatory Stage- cow becomes restless and isolated from the herd
The pelvic girdle (birthing canal) will begin to relax by allowing joints/ligaments to become more elasticized
Common visual cues- tail head ligaments relax, vulva swells, discharge clear mucous, udder enlargement
Internal cues- cervix relaxes and dilates, uterine contractions force the amniotic membranes to rupture which causes the water sac to break
The fetus will be moving into the birth canal in this stage
2. Active Labour- can be 30 minutes to an hour long, this stage begins when the calves legs enter the vagina
Internally- uterine and abdominal muscle contractions increase, fetus puts pressure on cervix causes full dilation
Common visual cues- the cow is very restless, feet and nose should be presented, contractions will occur every 15 minutes and progressively get stronger
2-3 minutes after birth the cow should be up and licking her calf to promote bonding and ensure the placental sack is not suffocating the calf
After 10-15 minutes, the calf should be standing and searching for the udder
Colostrum needs to be obtained in the first 12 hours after birth
3. Involution and Expulsion of Placenta- post delivery uterus contracts and placenta is expelled
If not expelled within 12 hours, this is referred to as retained placenta
Retained placenta can pose risk for infection in the cow
Do not force removal, try to let cow clean on her own
Can use estrus injection to promote cleaning when necessary, talk to your vet for more details or other options
There are risks associated with every step in parturition and therefore need to be managed properly to decrease death loss. Some of the risks and problems associated with calving will be explained in the next blog post.
