March 21, 2019 | Vol. 12 : No. 3

Angus Advisor

Our team of Angus advisors offer regional tips for herd management for the spring season.

Southern Great Plains

Spring-calving herds
Plan to implement estrous synchronization systems for heifers and cows. An excellent resource for this planning process is the Estrus Synchronization Planner at

Purchase artificial insemination (AI) supplies, acquire semen, and check facilities and equipment.

Consult your veterinarian about timing and product selection related to vaccination of cows prior to implementing an AI program. There is growing evidence that modified-live products administered within about 45 days prior to insemination may reduce success rate.

In this region, many operations rely on warm-season perennial forages as their primary grazing resource. However, most of these warm-season forages do not produce adequate forage availability until late April or early May.

As a result, early spring calving creates a large gap between nutritional requirements and nutrient supply. This gap must be filled with purchased or harvested feeds or cool-season forage to keep lactating cows from losing excessive weight and body condition.

The primary factor determining days to first heat (postpartum interval) after calving is the cow’s body condition the day she calves. However, excessive weight loss after calving is also associated with an extended postpartum interval and reduced first service conception rates.

Conduct breeding soundness exams (sometimes referred to as a BSE) for all herd sires.

Fall-calving herds
Determine your preferred timing for weaning, and inventory of supplies for veterinary items and feed or supplements.

If calves were vaccinated with modified-live vaccine products at branding, booster vaccinations can be administered at weaning. Alternatively, vaccinating two to six weeks prior to weaning and again at weaning is highly effective.

A coccidiostat (feed or water additive effective in controlling coccidiosis) is an important consideration on properties that have a history of coccidiosis.

General recommendations

New-generation ear tags are highly effective in controlling horn flies. To minimize the buildup of resistance, rotate the chemical class of tags used annually.

Justin Talley, Oklahoma State University livestock entomology, recommends this rotation: abamectin (year 1), organophosphate (year 2) and pyrethroid (year 3).

Follow label directions for number of tags per cow and per calf. In many cases, two tags per cow with no tag in the calf is the most effective strategy. Calves receive adequate product from the cow.

Figure 1: Season-long impact of the different tagging application periods on horn flies.
Click here for larger image.

Figure 1 shows results of Talley’s work looking at timing of fly tag application. April application resulted in better season-long control compared to later application.

Plan to remove ear tags as soon as possible once their effectiveness begins to decline.

Insect growth regulators (IGR) to be used in free-choice mineral products should be initiated in April before the fly population builds. A high percentage of the herd must consume the mineral consistently for this strategy to be effective. Neighboring cattle with heavy fly infestations will reduce the effectiveness of this strategy.

Introduced warm-season forages, such as Bermuda grass and Old World bluestem, should be fertilized in late April through mid-May. Approximately 50 pounds (lb.) of nitrogen (N) is required to produce about 1 ton of forage. Efficiency of nitrogen use is improved with multiple applications (two or three).

High-magnesium mineral supplements should be provided for cattle grazing cool-season forages through the month of April.

A moderate- to low-phosphorus (P) mineral supplement (10% phosphorus or less) is recommended for most classes of cattle and forage types during the lush spring season, when plants are growing.

Check with your Extension educator or forage agronomist to determine the most effective herbicide treatment to control sericea lespedeza.

Read the herbicide label for the most effective rate and timing of application. Other tools to help manage this invasive legume species include late-season prescribed fire and management-intensive grazing with goats.

Western Region

Fall-calving herds
Cows and calves are on cruise control.

Start planning for preweaning vaccinations. Continue your mineral supplementation program. Consider injectable mineral products in addition to loose, block and tub mineral products.

This is the time period of the year when fall-calving cows and calves should have very few problems with animal health.

Spring is an excellent time of the year to work on general repairs such as building fences and other facilities.

Also, if irrigated pastures are part of your forage resources during the summer months, this is the time to make repairs to irrigation systems before they are needed later.

Spring-calving herds
Prepare for the breeding season.

Decide on AI sires and get semen ordered early to avoid last-minute problems with semen delivery. The most important decisions each year in a purebred operation are sires.

Consider all information and try to find the bulls that combine expected progeny differences (EPDs), genomics, phenotypic traits and “old-fashioned” convenience traits like longevity, udder structure, disposition, mothering ability, feet and leg soundness.

Decide on a synchronization protocol if estrous synchronization is going to be used. Many excellent systems are available and many of the timed AI (TAI) protocols offer very satisfactory results.

  • Heat detection is the key to a good AI program unless you are using TAI.
  • Don’t overlook the importance of good semen handling.
  • Get bulls semen- and trichomoniasis-tested far in advance of the breeding season. If problems arise, replacement bulls can be located.
  • Focus on becoming a better grazing manager — it can have a huge impact on your overall bottom line.
  • Mineral supplementation is extremely important at this time of the year. I have discussed in detail in previous columns all of the different options available in this area.
  • Try to maintain the optimum level of body condition through the calving and breeding season.
  • Normally by late spring, forage resources are at their peak from both an energy and protein standpoint. Therefore, usually supplemental feeding is not needed at this time of the year.
  • Make certain that females and service sires are vaccinated at least 30 days prior to the start of the breeding season.
  • Treatment protocols and products should be on hand for both scours and pneumonia in suckling calves.
  • Late spring is a good time to spray fencelines and get irrigation ditches or lines in good repair if irrigated pastures or hay fields are part of your cattle operation.

Southeast Region

Fertility can be defined in multiple ways, but ultimately it is productiveness.

Often, fertility issues are not recognized until weeks or months have passed. To determine why a herd had poor conception or attempt to reduce infertility in the future, we must be keenly aware of body condition score (BCS) and focus on the three major variables impacting fertility: nutrition, genetics and health management.

These three components together result in either a poor, average or excellent conception or fertility rate. For this article, we will focus on cow breeding infertility issues.

Where it starts
For starters, nutrition during breeding is critical. Cattle need to be on a positive plane of nutrition (gaining weight) and in a 4-6 BCS.

Mature cows going into breeding require forage and/or supplement that has 60% total digestible nutrients (TDN) and 12% protein. If only the protein portion is present, cows will lose weight. They require both adequate parts energy and protein for the nutrition part of the equation. Big swings in the type of nutrition can also be a big disrupter for breeding conception; this can include changing to baleage or lush grass around breeding.

In the east, many herds have to consider the effects of toxic tall fescue. Breeding seasons in May and June are extremely disappointing when toxic endophyte fescue is the main forage available. Although fall calving helps, the growing calves and replacement heifers will be victims come spring, enduring long-term effects in their performance, as well as their development.

Cattle grazing novel (non-toxic) endophyte fescue had significantly better pregnancy rates for mature cows, 85.1% vs. 44.7% for cattle grazing endophyte-infested fescue. Calving rates for heifers on novel endophytes were 90.6% vs. 64.1%. The impacts of toxic endophytes in tall fescue are significant.

Research shows the presence of clover in tall fescue pastures dilutes some of the effects and helps improve gains in growing calves. Removing toxic fescue and planting a novel variety or some other grass is costly and has some risk, but it can certainly be a worthwhile project if conception rates are improved by 10% over the long term. When pasture renovation is not an option, it may be worthwhile to investigate chemical seedhead suppression.

On the other hand, if the feed and forage analysis suggest adequate nutrition is available prior to breeding and no known toxins are in the diet, thin cows are likely the product of genetics or disease. Genetically thin and narrow cows kill profitability. They need an extra three to six weeks postpartum to breed back, and it seems the shovel is never big enough. This goes for small-, moderate- and large-framed cattle.

We must be diligent to select replacements that will maintain an appropriate BCS within the boundaries of the operation’s resources. Cows that fatten too easily also have fertility issues.

Lastly, every operation should have vaccination and/or biosecurity measures against diseases (leptospirosis, trichomoniasis and bovine viral diarrhea, just to name a few). Work with your veterinarian to develop a protocol that fits your cattle herd.

Midwest Region

Endophyte-infested tall fescue continues to affect beef cattle production in the southeastern United States. Perhaps the top management and mitigation strategy is to replace “toxic” fescue with a novel endophyte fescue, which provides tolerance to drought and poor forage management, but produces fewer compounds that cause fescue toxicosis.

Not every acre of fescue is destined for renovation, because of leasing agreements, quality of soil, or any other reason a producer can dream up. Therefore, solutions to manage “toxic” fescue are needed.

One such idea is to reduce exposure to toxic compounds by removing seedheads in the late spring months.

Tall fescue seedheads, produced in late spring, contain at least three times the concentration of toxic compounds as leaf blades. Producers have clipped seedheads to reduce toxins for many years.

Recently, herbicides containing metsulfuron have been used to suppress seedheads. Grazing experiments in multiple states demonstrate a positive impact from seedhead suppression on cattle performance, partly due to reduced seedheads. Forage quality is generally improved after seedhead suppression occurs.

One downside to these management strategies is an overall reduction in forage production.

In 2018, my research group initiated a series of experiments to investigate a novel method of seedhead suppression in tall fescue.

We applied a prescribed burn to tall fescue plots (96% endophyte infection) in late winter (March 12 or April 10) and measured seedhead response. An April burn reduced seedheads by 50% and decreased ergovaline (one of the toxic compounds in fescue) by 33% in a June forage collection.

Like the other management options, forage production was also reduced, by 8% in our experiment over the course of the growing season. We plan to repeat this experiment over the next two years. We also intend to initiate a multi-year grazing experiment on the effect of late-winter prescribed fires in tall fescue forage systems at the MU Southwest Experiment Center in the upcoming months.

There are a number of options for mitigating effects of “toxic” tall fescue. Regardless of the method you choose, it is likely you’ll see cattle shed winter coats sooner, gain more weight and perhaps be more likely to become pregnant.

This is a no-brainer management tool for producers running cattle on tall fescue. For more information about tall fescue management or the research we are conducting, contact me directly.