Vet’s Voice: Plan now for heifer development
I’m sorry to say the ground hog saw its shadow a week ago on Ground Hog’s Day. That can only mean six more weeks of winter, but as most of you will agree, “How bad can six more weeks of winter like this be?”
Calving is beginning in some areas and will soon be in full swing. With calving on our doorstep it seems unusual to think about planning heifer development programs.
Through my 30-plus years of veterinary practice, I have seen producers lower the age of their cowherd’s puberty to the extent that heifers deliver their first calf at a approximately two years of age.
Selection for early puberty has allowed bull suppliers to market yearling bulls with large scrotal measurements capable of servicing females. The back side to this increased fertility is the breeding of suckling-heifers in late summer. The end result is heifers that deliver calves at approximately one year of age, which would mean the heifers were bred at three months of age. This is a problem for feedyards, and for selecting replacement heifers.
If selecting heifers from within the herd, be sure to select for fertility. These should be functional heifers with desired traits from cows that calve regularly and early in the herd. If raising terminal-cross calves, buy replacements.
Experience tells us the national cowherd must be starting to increase in size this year because we have seen more retained heifers an increase in Brucellosis vaccinations. We’ve seen heifers purchased at auctions receiving a premium of up to 40 cents per hundredweight for high-quality replacements (700-pound heifers bringing $1.85 per hundredweight, or more). When purchasing replacements, look for a source with known genetics which accomplish the goals set for the herd.
Once heifers are selected, choose a breeding date. Most experts recommend calving heifers 3-4 weeks before the cowherd. This allows time to monitor heifers exclusively during calving, and also provides an extra three weeks post-calving for heifers to recover before being re-bred along with the rest the cowherd.
It’s recommended that producers retrain the heifers which conceive through group artificial insemination (AI), or early in a bull breeding programs. This requires producers to select 25-30 percent more heifers. If 50 bred heifers are needed, begin with 70-75 heifers. This method allows producers to select for early calving females.
The three factors associated with attainment of puberty in heifers are: age, breed and weight.
Age and breed have already been selected. Weight was believed to be very important, and traditional development methods indicated that 14-month-old females should weigh 65 percent of her mature weight at breeding. This required a gain of 1.75-2 pounds per day when fed a moderately high-energy diet.
Recent Nebraska data suggests that heifers fed to 55 percent of their mature weight showed little difference in conception rates. This decreases the cost of development by utilizing low-quality forages in a time of high feed prices.
Another advantage to a lower weight at conception is producing a smaller-framed cow. These are generally one frame score less than heavier fed heifers. The central Plains area believes that 60-62 percent of mature weight is a good target due to harsh winter and spring conditions. This is why seeing a consistent gain, rather than a slow initial gain with an extreme gain or flush the last thirty days, is a move in the positive direction.
One of the most critical times in a heifer’s pregnancy is the first 30 days post breeding. Wyoming data reported almost a 20 percent decrease in conception when heifers were removed from high planes of nutrition during feedlot breeding and placed on pasture immediately after breeding. Avoid any sudden changes in nutrition for the first 60 days post breeding.
Heifer development is second only to feed costs in herd expenses. Consult with a veterinarian, nutritionist, or extension specialist to devise a program that fits your goals and feedstuffs available. Heifer development is a two-year cycle before ever seeing a return on the investment. Careful attention to detail and good management decisions will result in the long-term success and profitability of your ranch.
Dave Barz is a veterinarian at Northwest Veterinary Supply in Parkston, SD.