The Cow-Calf Manager:
Management at Turnout

Livestock Update, May 1998

John B. Hall, Ph.D., Extension Animal Scientist, Virginia Tech

By now most operations in Virginia have turned cow/calf pairs out to pasture. In many herds the breeding season is underway and the hardest part of the year is behind us. Management at or shortly after turnout has a big impact on calf growth and cow fertility. Most of the practices that need done are not new or earth shattering, but they warrant revisiting.

Castrate, implant and dehorn
Castration is best performed within 5 days of birth. This minimizes the stress and pain to the calf. If these practices were not performed at birth or during baby calf processing, they should be done by the time the calf is 30-60 days old. All male calves, that are not purebred and selected for future sires, should be castrated. Surgery or banding are the most common and effective methods of castration. If you are not familiar with the various techniques available contact you County Extension office.

Recently, several companies have been promoting delayed castration. Bulls do out gain un-implanted steers as calves. However, delayed castration is NOT recommended for the following reasons:

1. Bulls are discounted compared to steers. 500 lb bulls brought $5 to $12 less per cwt. than steers last year in Virginia.
2. Delayed castrated steer gained less as stockers than steers castrated as young calves (see table 1).
3. Welfare of the animal. Delayed castration causes more pain and stress than castration at a young age. The American Veterinary Medical Association encourages castration be performed at the earliest possible age.

Table 1. Average Daily Gain Of Early And Delayed Castrated Stocker Steers

Castration Method
Gain	Early 2.05 lbs/day	Delayed - surgical 1.78 lbs/day	Delayed - banded 1.58 lbs/day

Kansas State, 1992

Only a few cattle in Virginia need to be dehorned. However, just like castration it should be done as soon as possible. The best method for very young calves is electric dehorning which kills the cells responsible for horn growth. The horn bud then falls off. There are portable, rechargeable units that can be carried in the pickup or saddlebag. Spoons and Barnes dehorners are effective on older calves but it is generally a lot messier than the electric method.

Suckling calves should be implanted. Implanted calves will weigh 15-20 lbs more at weaning than un-implanted calves. Ralgro, Synovex-C, Compudose and Component E-C are all approved for use in nursing calves. Only Ralgro can be used in calves at birth. Calves need to be at least 45 days old before using the other implants. One implant of Ralgro, Component E-C or Synovex-C can be used in potential replacement heifers after they are 45 days old. My recommendation is to wait until they are 60 days old. Replacement heifers should receive only one implant in their lifetime. If replacement heifers can be identified shortly after birth implanting is not generally recommended.

Some producers and consumers are concerned about the use of growth implants in cattle. However, these concerns are unfounded. A 3-ounce piece of meat from implanted cattle contains 30 - 2,000 times less estrogen (a hormone) than a normal serving of milk, cabbage or eggs.

Vaccinations and Deworming
All calves should be vaccinated for Blackleg and Malignant edema (clostridial diseases) at turnout or when they are 3-4 months old. These vaccines are inexpensive and there are some one shot formulations available. Be sure to follow the label directions as to boosters etc to insure the maximum benefit from these vaccinations. Also, remember to give vaccinations in the neck to reduce damage to valuable portions of the product.

For young calves, deworming should be delayed until mid-summer. Research from the experiment station at Steeles Tavern demonstrated a 14 lb increase in weaning weight from mid-summer deworming. That was only one year's data. We are continuing research in this area, but there seems to be a benefit.

Older calves, especially fall born calves, will benefit from deworming at turnout and continuing on a strategic deworming program for the remainder of the summer. There are numerous effective dewormers on the market. The exact strategic deworming program varies with each product. Consult your veterinarian or extension agent about strategic deworming programs.

Mineral supplements
Mineral supplementation is needed in Virginia for proper growth of calves and fertility of cows. Usually, calcium, phosphorus, magnesium and trace minerals need supplementing. Soil fertility and forage quality will greatly effect mineral content of forages. Therefore, forage sampling should be used to decide what kind of mineral mix you need to buy or mix at home.

Research performed at Glade Springs, by Dr. Mark Wahlberg and co-workers, indicated that only high selenium trace mineralized salt with 20 % limestone was needed for cow/calf pair on the well-fertilized pasture there. Several county cattlemen's groups in Virginia are buying large quantities of mineral supplements based on forage tests. These groups have cut their mineral costs by $ 3-$7 per 50 lbs. There are many good mineral mixes available; however, some of them contain more ingredients or more expensive minerals than are needed. Knowing your needs can reduce you mineral costs.

This time of year mineral mixes should contain 12-14% Magnesium to prevent grass tetany. Some calcium and phosphorus may also be needed. Mixes should contain 6-12% calcium and 6-12% phosphorus, if supplementation of these minerals is needed. Table 2. Indicates the concentrations of important trace minerals that should be in mineral mixes fed to cow/calf pairs.

Table 2. Trace mineral concentrations needed in mineral mixes.

Mineral	4 oz/day	2 oz/day
Zinc	.18%	.36%
Copper	.09%	.19%
Manganese	.18%	.36%
Iodine	.0026%	.0052%
Selenium	.0026%	.0052% From Wahlberg, 1997 There are many good mineral mixes on the market. Just remember to buy the mineral mix you need to match your forage and be aware of cost. Also, instructions for homemade mineral mixes can be found at your county extension office. Next month: Feed budgeting and creep grazing Visit Virginia Cooperative Extension