| IN THIS ISSUE:
- Ergot issues in Iowa in 2013
- Research update: Influence of supplemental vitamin C
- Traveling the beef industry here and there
- Maintaining cow body condition in frigid weather
- Announcements and Updates
Ergot issues in Iowa in 2013
By Joe Sellers, ISU Extension and Outreach beef program specialist and Steve Ensley, ISU veterinary toxicologist
Ergot contamination of forages and small grains was an emerging issue in 2013. The cool wet spring in Iowa in 2013 allowed the fungus that produces ergot, Claviceps purpura, to increase in prevalence in forages and small grains. Claviceps purpura produces a group of chemicals called ergot alkaloids. The ergot alkaloids cause vasoconstriction but can have many different clinical signs produced because of the effect these group of compounds have on the animal.
In the summer, heat intolerance is caused by ergot alkaloid ingestion. In the winter, animals can have poor circulation causing the tips of the tail, tips of the ear and the hoof wall of animals to fall off. Animals have a reduced ability to with stand cold temperatures when they are consuming ergot alkaloids. Fescue grass contains a similar ergot alkaloid compound that is produced by an endophyte that infects fescue, Acremonium coenophialum. This endophyte produces the ergot alkaloid, ergovaline. Ergovaline causes the same clinical signs that the other ergot alkaloids cause that are produced by Claviceps purpura. Several Iowa herds experienced poor reproduction and late term abortions, as a result of extremely high alkaloid consumption.
Since high levels of ergot were present in Iowa pastures, Iowa Beef Center staff were concerned how much remained in hay harvested this summer when sclerotia were present. In the fall of 2013, 35 samples of forage and hay were collected across southwestern Iowa to determine ergot alkaloid concentration. Twenty-six of these 35 samples contained ergot alkaloids. There were only 9 samples that had no detectable concentration of alkaloid. These forages were harvested early (before June 15) or late (after July 15), when the sclerotia that produced the alkaloids were not present.
Eleven of the hay samples contained over 300 ppb alkaloids. Most of these higher levels were found in hay containing fescue in the grass stand. The higher the concentration of ergot alkaloids there are in the feed, the more adverse clinical signs will be seen. Grazing animals in Iowa will be exposed to ergot alkaloids produced in endophyte-infected fescue grasses during the grazing period. Hay produced in Iowa without fescue in the stand typically does not contain any or a small amount of ergot contamination from Claviceps purpura. The difference this year is that there is a high level of ergot contamination in the hays produced, and cattle also may have ingested additional alkaloids from stockpiled fescue grass. The effects of Acremonium coenophialum infection and Claviceps purpura infection are additive.
Producers who are feeding mature grass hay harvested in late June or early July should monitor performance of cows fed this hay, and supplement with other feeds to dilute the impact of the alkaloids in the hay. Forage nutrient analysis of the 35 lots of hay also found that most of this mature grass hay was short in energy and marginal in crude protein, so supplements that supply both energy and protein, such as corn co-products, will be effective parts of the diet.
For more information discuss these issues with your local veterinarian or your ISUEO beef specialist.
Research update: influence of supplemental vitamin C on growth performance and carcass characteristics in finishing steers fed high sulfur diets
By Danielle Pogge, animal nutrition graduate student (major professor -- Stephanie Hansen)
Increasing the inclusion rate of ethanol industry co-products to feedlot diets may be exposing cattle to greater amounts of dietary sulfur. High sulfur diets have been repeatedly reported to decrease growth performance, health, and carcass traits of feedlot cattle. Cattle naturally produce vitamin C in their liver; therefore, cattle have no known supplemental vitamin C requirement. However, Japanese researchers have observed a decrease in plasma vitamin C concentrations during the fattening period, which may suggest that vitamin C production may not be adequate to meet finishing cattle needs. Other researchers have observed an increase in marbling score and rib-eye area when vitamin C was supplemented during the finishing period. Given previous research findings, we hypothesized that supplementing vitamin C during the finishing period might help to alleviate some of the negative effects of high sulfur diets in cattle.
In a 149-day finishing trial, we investigated the effect of a rumen-protected supplemental vitamin C (10 g/steer/day) in calf-fed steers consuming a high sulfur (0.55%) finishing diet. Supplementing vitamin C prevented a decrease in plasma vitamin C throughout the finishing period and increased the marbling scores from high Select to low Choice when compared to the unsupplemented high sulfur steers. Alternately, in yearling steers, increasing the dose of supplemental vitamin C (0, 5, 10 or 20 g/steer/day) in a high sulfur (0.55%) diet for an average of 102 days linearly decreased dry matter intake, tended to increase feed efficiency, and increased rib-eye area by approximately 0.65 in2; while no difference in marbling score was noted (Table 1).
Overall, the findings of our experiments yielded differing results of how supplemental vitamin C is impacting finishing steer growth performance and carcass traits; however, these differences may be attributed to individual animal variability or differing genetics of the steers that were used in these studies. Further research is needed to better understand how vitamin C supplementation to finishing cattle is influencing performance, marbling potential, and rib-eye area.
Traveling the beef industry here and there
By Dan Loy, IBC director
In December I had the unique opportunity to travel and learn about the needs of the beef industry both across the state of Iowa and in country of Brazil. While the temperature and language were different, the similarities were remarkable.
As part of the periodic “needs assessment” of the Iowa Beef Center, we recently traveled more than 1400 miles across Iowa to seven listening sessions. Knowing the issues and challenges facing Iowa beef producers helps guide our programming and keeps us relevant.
These sessions were hosted by each of the Regional Beef Specialists. Dr. Patrick Gunn summarized the sessions into eight recurring themes, including these three:
-- Grazing land access and utilization.
-- Effective integration of young and beginning cattle producers.
-- Improving beef production efficiency including both feed efficiency and reproductive efficiency.
Read all of this column on the IBC website.
|Maintaining cow body condition in frigid weather
By Patrick Gunn, ISU Extension cow-calf specialist
It’s no secret that winter weather and associated wind chill increases the amount of dietary energy needed for cows to maintain body condition.
The traditional rule of thumb is that for every degree (actual or wind chill) below 30° F, producers need to increase daily energy delivery by 1% for cows in a moderate body condition score (BCS) of 5 or 6.
Often overlooked, however, is the added energy that thin (< BCS of 5) or wet cows need in order to maintain body condition in the same frigid environment.
In most circumstances, those thin and/or wet cows need 2-3% (as opposed to 1%) more daily dietary energy to maintain body condition.
While cows will typically increase forage intake slightly as weather turns for the worse, their ability to ingest enough added forage to meet these requirements is unlikely, if not impossible, depending on the extremeness of weather conditions. Perhaps more important to producers, however, is not how much more energy a cow needs, but how much more feed.
The following example rations have been developed with the Iowa State University BRaNDS ration balancing program to illustrate how lower temperatures and BCS impact feed requirements for cows in their third trimester of gestation.
|Feed, pounds as-fed
||15° F, clean hide, BCS 5
||5° F, clean hide,
|5° F, clean hide,
|1st cutting hay
As you can see, decreasing temperature and/or BCS increases the need for supplemental corn when cows are assumed to be on round bales of first cutting hay.
However, these are just examples; therefore, consult with the team of experts you have assembled including your nutritionist and beef extension specialist when developing rations for adverse weather conditions.
Contact us at:
Iowa Beef Center
313 Kildee Hall
Iowa State University
Ames, IA 50011-3150
|Announcements and updates
Cornbelt Cow-Calf Conference
No preregistration necessary for this annual showcase event for the state's cow-calf producers set for Jan. 18 at the Bridge View Center in Ottumwa. Read more.
Farming for the Future: Emerging Opportunities in Livestock Production
The Coalition to Support Iowa’s Farmers hosts this annual event this Thursday from 9:30 a.m. to 4 p.m. at the Scheman Building in Ames. Preregistration is required. See the agenda and link to the registration form on the CSIF website
2014 Driftless Region Beef Conference
Register now for the 2014 Driftless Region Beef Conference at the Grand River Convention Center in Dubuque, Iowa, set for Jan. 30-31. Cost is $80 per person before midnight Jan. 22, and increases to $100 after that time. See links to the program, sponsors and registration information pages from the conference website
Beginning Farmers Conference
The ninth annual Beginning Farmers Conference will be held Feb. 1 at the Scheman Building in Ames. The keynote speaker will be Pat Grassley, chair of the Iowa House Agriculture Committee. See the conference website.