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Previous issues of the BEEF Cattle letter
Issue # 490
June 7, 2006
Improving Conception Rates - Rory Lewandowski, Extension Educator Ag/NR Athens and Hocking Counties
The conception rate achieved during the breeding season can have a big impact on the profitability of the cow/calf operation. A cow must produce a calf each year and that starts with getting bred in a timely manner and maintaining the pregnancy through calving. There are several factors that can influence conception rates, and by giving some management attention to them, conception rates can be improved.
The first factor to consider is nutrition. Remember that there is a hierarchy of nutrient use that follows this order: Maintenance, Growth/Development, Lactation, Reproduction and Fattening. When nutrients are limiting, the first use of those nutrients will be to keep the animal alive by meeting basic body maintenance requirements. Notice reproduction is toward the bottom of the list, indicating that the cow must be in good body condition and have access to feedstuffs that have a high nutrient content, especially energy, in order to achieve conception and pregnancy. Cows that may have been thin at time of calving (body condition score <5) will often be delayed in resuming an estrous cycle and can have lower conception rates. Cows should be a body condition score of 6 to 6.5 (scale 1-9) by the start of breeding season to insure high conception rates.
Age of the cow can influence conception rates. Yearling heifers in good body condition and weighing 65% of their mature adult weight may achieve higher conception rates than mature cows with a nursing calf since they do not have the nutrient demands and stress of lactation. Heifers calving as two year olds are candidates for lower conception rates if nutrients are not adequate or body condition is not good, since they must meet nutrient needs for maintenance, growth, and lactation before reproduction. Old cows nearing the end of their production life may also have lower conception rates compared to mature cows in good body condition on good quality pasture.
Environmental conditions, particularly temperature can impact conception rates. It has been well documented that periods of hot weather can cause up to an 8 to 10 percent decrease in conception rates. Part of this is explained by early embryonic mortality rather than lowered fertility. Going back to some of the comments I made in the introduction to this newsletter, some cattle will have higher conception rates because of their genetic makeup that enables them to survive more efficiently under the topography, pasture type, and nutritional conditions that are provided to them.
Herd health must also be considered when striving for maximum conception rates. A vaccination program developed from consultation with your veterinarian is one necessary step. Consider vaccinations against Vibro, Lepto, IBR, PI3, BVD and BRSV. Make sure your bull passes a breeding soundness exam.
Finally, monitor the bull to cow ratio. Typically it has been recommended to use one bull with 25 to 35 cows for a mature bull and to lower this ratio to 10 to 20 cows for a yearling bull. Note that bulls in good body condition, on healthy feet and legs and with a high libido (sex drive) may often surpass these ratios and breed more cows.
Conception is the first step in producing next year's calf crop and attention to some of the factors influencing conception rate can result in improved conception rates.
Forage Focus: Do we really need to "baby" forage seedings? - Jeff McCutcheon, Knox County Extension Educator, Ag & NR
Forage producers understand that the stage of growth determines when to harvest. For example, to optimize both yield and quality, grasses should be harvested in the boot to early seed head emergence time period and legumes should be harvested in the bud stage. But is this also important in the seeding year? Since we spent so much time and money to plant the forage shouldn't we treat it carefully, take fewer grazings/cuttings, to give it a chance to establish? To answer these questions let's review grass and legume growth.
There are three basic growth stages in grasses that producers should be able to recognize, they are: 1) vegetative; 2) elongation; and 3) reproductive.
The vegetative stage is leaf growth. The growing point is compact and near the soil surface. Grazing/cutting at this time typically only removes older parts of the leaves. Each tiller will sustain a critical number of leaves. Newer leaves shade older leaves. Generally older and lower leaves die at the same rate as new leaf growth. Shading by growing leaves at this stage can cause small, non-flowering tillers to die.
Elongation, as its name implies, is the stage where the stem lengthens. Some call it jointing. Stems elongate in response to changing day length and temperature. The growing point is elevated and can be removed by grazing/clipping. If the active growing point is removed, then leafy growth will develop from dormant basal buds as new tillers. Most cool season grasses produce reproductive stems only in the spring after a period of short days/long nights and cold weather, which means after removing the seed stems; only leafy vegetative growth will be present for the remainder of the growing season.
When the developing seed head is in the uppermost leaf sheath, the plant has reached boot stage. This is the start of the reproductive stage. This stage is when the seed head develops, pollination occurs, and seed develops. As the seed heads develop, they produce plant hormones which retard the development of basal buds. This "apical dominance" reduces forage re-growth. Removing seed heads soon after they emerge will reduce tiller death due to shading and reduce the length of time that new tillers are suppressed by dominant reproductive tiller.
Legume growth is classified a little differently 1) vegetative, 2) bud, and 3) flowering. These stages are controlled by day length and temperature. Reproductive development will occur during each growth cycle. Legumes have many potential growth points. These are located at the stem tip, leaf-stem junction and most legume species also have dormant buds at the crown. These crown buds will produce new, leafy growth when growing stems are grazed or clipped.
The location of the growing points determines the legume's response to grazing/clipping. The growing points on alfalfa, red clover, and birdsfoot trefoil are susceptible to removal by grazing/clipping. Re-growth will come from dormant crown buds and lower stem branches when the growing stems are grazed or cut. White clover's growing points are on stolons and are too low to be removed by grazing, but can be damaged by trampling.
Principles that apply to established stands also apply to new seedings. Most cool season grasses need a cold period to induce flowering. New seedings will not show reproductive development during the seeding year. These could be harvested when leaves are fully elongated but before leaf death occurs. To encourage tillering, grazing or clipping when grasses reach 6-8 inches would be beneficial. Grazing should be done on firm soils and with a high stocking density and short duration. In other words, use enough livestock to reach your target residual in 3-5 days. Over grazing should be avoided.
Won't grazing/cutting early effect root development? Remember the "take half, leave half" rule? Everyone who has attended a grazing school has seen the data from the classic study by F.J. Crider that was published in 1955. This data showed that in grasses if you removed 40% of the leaf volume you would not stop root growth. Removing 50% of the leaf volume only stopped 2% of the roots growing. At 60% leaf removal 50% of the roots stopped growing. All of the roots stopped growing at 80% leaf removal. If anything, err on the side of leaving just over half of the leaf area as residual with a new seeding.
Spring seeding of alfalfa should be harvested in the bud stage to optimize both yield and quality. Depending on the weather this could happen 60-70 days after emergence. If seeded with a companion crop then it should be harvested as hay when the companion crop is in the boot stage. After the first cutting follow a normal cutting schedule. Lots of data suggest that with a new alfalfa seeding you should avoid a late cutting after the first week of September in Ohio.
Photo below taken 6/7/06: Alfalfa field seeded with a companion nurse crop of oats in late March, harvested the first time while the oats were in boot stage on May 30, 2006.
Fertilizing Forage Crops - Doug Beegle, Department of Ag Sciences, Penn State
Even with high fertilizer prices, we need to make sure we are meeting the nutrient needs of forage crops if we want optimum production. Forage crops have a large appetite for nutrients, removing around 50 lb N, 15 lb P2O5, and 50 lb K2O per ton of hay equivalent harvested. Many fields that get a lot of manure in the corn part of the rotation have good reserves of nutrients that can be used by the forage crops, at least for a while. Here is a place to save some dollars and utilize these banked nutrients rather than applying fertilizer. Fields receiving little manure or that are late in the forage rotation can have fairly low soil test levels and thus need fertilization. This is where you need to prioritize your forage fertility dollars. The key is to recognize these differences and fertilize wisely.
As always, begin with a soil test. Even though it maybe the last minute, the Ag Analytical Services Lab at Penn State normally has about 2 day turn-around with soil samples. So if you overnight your samples to the lab and have signed up for free web access to your results, you could sample at harvest and still have your results in time to make topdressing decisions. Other labs have similar service.
The ideal management for forage crops is to build the soil levels at least into the optimum before seeding. Then if the soil test levels are above optimum at that point, you can draw them down for a while until they are in the optimum range and then maintain the soil in the optimum range throughout the remaining life of the stand by replacing crop removal.
Timing of fertilizer applications to forages will depend on the situation. If the soil tests are in the optimum range and the recommendations are relatively small, timing is not very critical. The most common timing is after first cutting. For larger applications on low testing soils, split applications are usually more efficient. Apply some early in the season and the balance in the early fall. This minimizes luxury consumption of nutrients like potassium and the fall application may improve winter survival of the forage.
What about manure on forages? Manure is excellent on grass forages which need N, P, and K. Splitting applications in the spring and immediately after each harvest is recommended for maximum nutrient use efficiency and to avoid problems with injury. Base the rate on the N requirement of the grass forage which is 50 lb/ton of expected yield for the upcoming cutting. Remember that typically manure N will only be about 35% available compared to fertilizer. See table 1.2-14 in the 2005-2006 Agronomy Guide for more specifics.
On legumes, manure is a good source of P and K but since they do not need the N, it will be essentially worthless to the crop. Also, in mixed grass-legume stands or where there is some weed pressure, the N in manure can stimulate the grass and weeds and crowd the legume out of the stand. Old stands that will soon be rotated out of forage are usually the best place to go with the manure rather than newer stands.
Weekly Roberts Agricultural Commodity Market Report - Mike Roberts, Commodity Marketing Agent, Virginia Tech
LIVE CATTLE in Chicago (CME) closed off $0.15/cwt on the JUNE'06LC at $80.175/cwt, up $0.105/cwt from last week. The AUG'06LC futures finished down $0.625/cwt from Friday's close at $80.675/cwt and $0.20/cwt below a week ago. Futures were pressured by profit taking and disappointing export news from South Korea seen as delaying U.S. beef purchases. Cash cattle sold to $2/cwt higher in lively trading at $83/cwt -$83.50/cwt on Friday with the JUNE'06LC finishing equal to $80.175/cwt. Funds were active mostly in AUG'06LC buying while locals and other traders were selling an estimated CME volume of 18,000 lots. Futures turned higher in early trading after initial selling but headed south on profit taking. The discount of futures to cash price and higher beef prices supported futures at times on Monday. USDA placed the choice cutout at its highest since March 1 up $0.73/cwt at $153.45/cwt while the select cutout slid $0.06/cwt to $131.07/cwt. Late Monday USDA placed the daily live cattle slaughter at 126,000 head, up 24,000 head from last year and 5,000 head last week. Cash sellers should carry all risk in the cash market at this time. Corn prices are generally seen as declining somewhat.
FEEDER CATTLE at the CME were slightly off $0.650/cwt in the AUG'06FC contract closing at $109.575/cwt and the SEPT'06FC down $0.525/cwt at $108.850/cwt. Feeders followed the back months of live cattle down in spite of lower corn prices. Some funds bought while others sold … essentially a wash. Profit taking and the feeder cattle premium to the CME feeder cattle index pressured the market. The latest CME feeder cattle index was up $0.38/cwt at $106.322/cwt. Cattle feeders are carrying all risk in the cash market at this time having stepped out of short positions.
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BEEF Cattle is a weekly publication of Ohio State University Extension in Fairfield County and the OSU Beef Team. Contributors include members of the Beef Team and other beef cattle specialists and economists from across the U.S.
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Fairfield County Agriculture and Natural Resources
