CARSTAIRS, Alta. — Next to feed costs, the greatest expense on a ranch is cow depreciation so improving momentum and longevity in the herd is important.
Increasing longevity starts with heifers, said Elizabeth Homerosky of Veterinary Agri Health Services at Airdrie, Alta.
When it comes to replacement heifer management, it is better to look for a reason for them to leave as opposed to trying to find a reason for them to stay, she said at a cattle clinic held in Carstairs, Alta., Sept. 19.
Heifer development can improve overall fertility and performance in a herd.
“The more you treat them like a cow, the better cows they will be. If you pamper her and subsidize her through the first calf, she is always going to be looking for the feed truck. She will never be the cow she could have been,” she said.
There are several parts to a heifer development program at pre-weaning, weaning and pre-breeding.
Vaccination programs start early.
Heifers tend to have lower levels of immunity and can be more susceptible to infectious disease so the vaccination program should start with a modified live vaccine for diseases like bovine rhinotracheitis (IBR) and bovine viral diarrhea (BVD).
Start with a five-way modified live respiratory vaccine plus protection against Mannheimia haemolytica, which causes pneumonia around weaning.
Ensure vaccines have a fetal protection (FP) label claim. This pertains to the BVD virus. If a bred cow comes in contact with the virus and the fetus gets infected, the calf is born persistently infected and will continue to shed the virus throughout its life.
“Any animal that is of breeding age or close to it I want to make sure I am giving a vaccine with a fetal protection label claim in it,” she said.
Heifers should get a five-way booster at least once before breeding.
The earlier vaccine causes an immune response but it starts to slip back. When a booster is given about four weeks later it creates a bigger antibody response.
Another program includes a seven- or eight-way clostridial vaccine plus Histophilus somni protection.
Talk with the veterinarian about deworming because a fecal egg count may be recommended to see how many parasites are present.
“We have a lot of resistance to ivermectin now so we are trying to make sure whatever product we have left, we are ensuring they are going to work for a long period of time,” she said.
When selecting replacements consider these red flags:
- hard birth
- heavy birthweight
- mother has poor disposition
- dam did not have good udder
- sire or dam have poor feet or eyes
- wrong breed composition
- not born by second 21-day breeding cycle
“It is not coincidence that some of your most fertile cow families, where you’ve got mother and daughter or mother and granddaughter, calve a few days apart,” she said.
“They are more prone to have higher fertility.”
At weaning consider:
- Poor performance: beware of heavy milking dams. A fat heifer on pasture will put fat into the udder and will not produce as many milk-producing cells.
- Large frame size.
- Poor conformation.
- History of disease or treatment.
“If she has been treated for scours or pneumonia, she doesn’t get a chance to enter the breeding herd.”
The heifer probably did not get enough colostrum or is just not as healthy as herd mates.
Past recommendations said heifers can be bred at 65 percent mature body weight but new information suggests they can be lighter weight at 50 percent.
“In Western Canada, that is getting a little bit risky. Our heifers are probably 55 to 60 percent range and they catch up later. There are a lot of economic advantages to do that,” Homerosky said.
Research on developing heifers looked at several systems.
In the early gain system heifers were weaned and developed in a drylot and received silage and grain. They gained most of their weight through the winter-feeding period.
The late gain system mimics a backgrounding system. Heifers are given rations where they put on about a pound a day throughout the winter and gains are stepped up later in the spring to put on about 2.5 lb. per day.
Conception rates for both systems were around 85 percent, but the late gainers seemed to conceive better in the first round of breeding. They also consumed 12 percent less feed so they are cheaper to raise and appeared to have better fertility.
Longevity of early-, even- and late-gain systems was also compared. Over time, late-gain-system heifers were more likely to stick around.
In a drylot system, heifers are more pampered with feed delivered to them while late gainers develop better grazing habits. They go through a low weight gain over winter and then faster gains once they are eating grass. By breeding time, they should be around 85 percent mature body weight by the time they deliver the calf.
Switching to a late-gaining system takes years to perfect and may not work well for herds in winter calving programs, Homerosky said.
Look at heifers six weeks before breeding.
If they are not heavy enough, they can put on weight at this time. They can also get a vaccine booster. This includes IBR, but it causes some inflammation in ovaries for one or two cycles.
“If she hasn’t seen that vaccine since weaning, and you are giving it pre-breeding, you want to give it 30 days before you put out the bulls or AI her because her fertility may be reduced for a short while she responds to that IBR fraction in the vaccine,” she said.
Homerosky favours the Estrotect sticker. It is placed over the tail head about six weeks before breeding. As mounting occurs the silver surface on the sticker is rubbed off and an indicator colour appears to show a true standing heat.
To view a video on its use, visit bit.ly/2ntPwhH.
This can also be an early indicator of the infertile females and they can be culled during a better marketing period rather than waiting until later in the fall when prices start to turn down.
A heifer needs to have one cycle before being exposed to a bull to get pregnant and maintain it.
Heifers may also be synchronized so they will get pregnant at the same time.
Getting heifers pregnant in the first cycle means their calves have a 21-day advantage and will be heavier at weaning time. Those caught in the first cycle in their first year tend to stay longer in the herd for more calving seasons.
Select bulls with calving ease expected progeny difference numbers rather than birthweight EPD. Do not use calving-ease bulls on mature cows. Cows can handle more and give up too much performance on the calves.
Consider using composite or terminal sires on heifers.
Pregnancy check about 35 days after bulls are removed to find those that did not conceive, so they can be culled.
After pregnancy checks, turn the bulls back in herd. They maintain a herd mentality and get more exercise by grazing and moving to water. They do not fight as much in the spring because they maintained their hierarchy throughout the year.
Winter feeding is easier with bulls in the herd. It produces better protection in winter and keeps bulls’ testicles in better shape.