Integration of Pasturing Systems for Cattle Finishing Programs

A 3-year study, using 84 fall-born and 28 spring-born calves of similar genotypes, was conducted to integrate pasturing systems with drylot feeding systems. Calves were started on test following weaning in May and October. Seven treatments were imposed: 1) fall-born calves directly into feedlot; 2 and 3) fall-born calves put on pasture with or without ionophore and moved to the feedlot at the end of July; 4 and 5) fall-born calves put on pasture with or without ionophore and moved to the feedlot at the end of October; 6 and 7) spring-born calves put on pasture with or without ionophore and moved to the feedlot at the end of October. A bromegrass pasture consisting of 16 paddocks, each 1.7 acre in size, was available. Each treatment group had access to 1 paddock at a time and was rotated at approximately 3-day intervals. In the feedlot, steers were provided an 82% concentrate diet containing whole-shelled corn, ground alfalfa hay, and a protein, vitamin and mineral supplement containing ionophore and molasses. As pens of cattle reached about 1150 lb. average live weight, they were processed and carcass traits were evaluated. Pasture daily gains were highest for cattle on pasture for the longest duration (P < .03), and overall daily gains were highest for drylot cattle (P < .01) and decreased with increased time spent on pasture. Although differences among treatments existed in numerical scores for yield and quality grades (P < .05 and P < .03, respectively), all treatments provided average yield grade scores of 2 and quality grades of low Choice or higher. Use of four production costs and pricing scenarios revealed that fall-born calves placed on pasture for varying lengths of time were the most profitable (P < .04) among the treatments. Furthermore, employing a 5% price sensitivity analysis, indicated that fed-cattle selling price had great impact on profit potential and was followed in importance by feeder purchase price and corn grain price. Overall, these findings should provide significant production alternatives for some segments of the cattle feeding industry and also lend substantial credence to the concept of sustainable agriculture.

Integration of Pasturing Systems for Cattle Finishing Programs: A Progress Report

A three-year study was conducted to integrate pasturing systems with drylot feeding systems. Each year 84 fall-born and 28 spring-born calves of similar genotypes were used. Fall-born calves were started on test in May, and spring-born calves were started in October. Seven treatments were imposed: 1) fall-born calves directly into the feedlot (28 steers); 2 and 3) fall-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of July (14 steers in each treatment); 4 and 5) fall-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of October (14 steers in each treatment); and 6 and 7) spring-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of October (14 steers in each treatment). Cattle on pasture receiving an ionophore gained faster (P=.009), but lost this advantage in drylot (P>.10). Overall, cattle started directly in the feedlot had higher gains (P<.001). Cattle receiving an ionophore on pasture had lower KPH than those that did not receive an ionophore (P<.01). Treatment influenced yield grade (P<0.001), although all treatments were YG 2. The percentage of cattle grading Prime and Choice was 75 % or higher for all treatment groups. The results show that using an ionophore improved pasture gains and that pasture treatments did not adversely influence yield and quality grades.

Integration of Pasturing Systems for Cattle Finishing Programs: A Progress Report

This progress report presents the findings of the first two years of a multi-year study. Each year 84 fall-born and 28 spring-born calves of similar genetic background were used to evaluate the incorporation of rotational pasturing systems into cattle finishing programs. The fall-born calves were started on test on May 7, 1996, and May 8, 1997, whereas the spring-born calves were started on test on October 1, 1996, and September 13, 1997. A total of seven treatments were imposed: 1) fall-born calves directly into the feedlot; 2) fall-born calves put on pasture and receiving an ionophore and moved to the feedlot on July 30, 1996, and July 29, 1997 in the first and second years, respectively; 3) fall-born calves put on pasture without an ionophore and moved to the feedlot on July 30, 1996 and July 29, 1997, in the first and second years, respectively; 4) fall-born calves put on pasture and receiving an ionophore and moved to the feedlot on October 22, 1996, and October 21, 1997, in the first and second years, respectively; 5) fall-born calves put on pasture without an ionophore and moved to the feedlot on October 22, 1996, and October 21, 1997, in the first and second years, respectively; 6) spring-born calves put on pasture and receiving an ionophore and moved to the feedlot on October 22, 1996, and October 21, 1997, in the first and second years, respectively; and 7) spring-born calves put on pasture without an ionophore and moved to the feedlot on October 22, 1996, and October 21, 1997, in the first and second years, respectively. Cattle receiving an ionophore on pasture gained more rapidly; however, cattle without access to an ionophore gained more rapidly in drylot thus negating the advantage obtained on pasture. Overall daily gains and feed conversions in drylot only, improved with increasing numbers of days fed in drylot; however, this may not be very cost effective. At similar end weights no real differences were observed in yield grades among the treatments; however, for fall-born calves the percentage grading Prime and Choice was higher for cattle fed longer in drylot.

Integration of Pasturing Systems for Cattle Finishing Programs: A Progress Report

In this study, 84 fall-born and 28 spring-born calves of similar genetic background were used to evaluate the incorporation of rotational pasturing systems into cattle finishing programs. Because the second-year trial is not complete, this report will include only the first year of the five-year study. Seven treatments were imposed: 1) fall-born calves put directly into the feedlot on May 7, 1996; 2) fall-born calves put on pasture and receiving an ionophore and moved to the feedlot on July 30, 3) fall born calves put on pasture on May 7 and not receiving an ionophore and moved to the feedlot on July 30; 4) fall-born calves put on pasture on May 7 and receiving an ionophore and moved to the feedlot on October 22; 5) fall-born calves put on pasture on May 7 and not receiving an ionophore and moved to the feedlot on October 22; 6) spring-born calves put on pasture on October 1 and receiving an ionophore and moved to the feedlot on October 22; and 7) spring-born calves put on pasture on October 1 and not receiving an ionophore and moved to feedlot on October 22. Performance data showed that cattle on pasture receiving an ionophore had higher gains than those not receiving an ionophore on pasture. This trend was reversed in the feedlot period. Yield grades were not greatly influenced by treatment, although quality grades tended to be higher for older cattle and those cattle that were in drylot for a longer period of time.

Heat Stress In Feedlot Cattle: Producer Survey Results

The weather on July 11 and 12, 1995 was a deadly combination of high temperature, high relative humidity, no cloud cover and no wind. The combination of heat and humidity has been matched only five times in Iowa’s 101 years of weather records. Estimated cattle death loss in a 13-county area of West Central Iowa was 3,750 head or 2.32% of the cattle on feed. A survey of 36 beef producers with 9,830 head of cattle on feed in 81 lots was summarized. Thirty-five lots with shade (24 square feet per head) reported an average death loss of .2% as compared to 46 lots without shade with losses of 4.8%. Producers reported a disproportionately higher death loss in dark-hided cattle. Non-shaded lots facing south, southwest, or west had higher death loss than lots facing east or southeast. Heavier animals were more susceptible to heat stress. Lots containing heifers that were fed MGA had lower death loss ( 3.8% vs. 6.2% ) as compared to lots with heifers but not receiving MGA.

Effect of MGA on Performance, Sexual Behavior, Carcass Quality and Tenderness in Mixed-Sex Pens of Cattle

The effect of MGA in mixed pens of steers and heifers was evaluated over a three-year period at the ISU Armstrong Research Farm near Lewis, Iowa. Two pens of approximately 40 head were fed diets with or without MGA in each of three replications. Estrus and riding activity was monitored using the Heat Watchâ system. At slaughter, in addition to routine carcass data collection, a rib sample was collected from each carcass for tenderness evaluation. There was no effect on dry matter intake due to MGA treatment. Mixed-sex pens that were fed MGA were 4% more efficient than controls. MGA-fed steers gained similarly to control steers. MGA fed heifers gained 8% faster than control heifers. MGA highly reduced measures of estrus and riding activity throughout the feeding period. MGA feeding improved marbling and tenderness measured in both steers and heifers. These data suggest that MGA has potential to improve performance, quality grade and tenderness in mixed pens of steers and heifers.

Evaluation of Condition Scoring of Feeder Calves as a Tool for Management and Nutrition

Two experiments were conducted to evaluate the effects of body condition scores of beef calves on performance efficiency and carcass characteristics. In Experiment 1, 111 steer calves were stratified by breed and condition score (CS) and randomly allotted to 14 pens. The study was analyzed as a 2 x 3 factorial design, with two breeds (Angus and Simmental) and three initial CS (4.4, 5.1, and 5.6). In Experiment 2, 76 steer calves were allotted to six pens by CS. The resultant pens averaged 3.9, 4.5, 4.7, 5.0, 5.1, and 5.6 in CS. Calves in both studies were fed a corn-based finishing diet formulated to 13.5% crude protein. All calves were implanted with Synovex- SÒ initially and reimplanted with Revalor-SÒ. In Experiment 1, 29-day dry matter intake (lb/day) increased with CS (17.9, 18.1, and 19.1 for 4.4, 5.1, and 5.6, respectively; p < .04). Daily gain (29 days) tended to decrease with increasing CS (4.19, 3.71, and 3.26; p < .13). Days on feed decreased with increasing CS (185, 180, and 178d; p < .07). In Experiment 2, daily gains also increased with decreasing initial CS for the first 114 days (p < .05) and tended to increase overall (p < .20). In Experiment 1, calves with lower initial CS had less external fat at slaughter (.48, .53, and .61 in. for CS 4.4, 5.1, and 5.6, respectively; p < .05). This effect was also noted at slaughter (p < .10), as well as at 57 days (p < .06) and at 148 days (p < .06) as measured by real-time ultrasound. Measurements of intramuscular fat and marbling were not different in either study. These data suggest that CS of feeder calves may be a useful tool for adjusting energy requirements of calves based on body condition. Also, feeder cattle may be sorted into outcome or management groups earlier than currently practiced using body condition and/or real-time ultrasound.

Effect of Early Weaning of Beef Calves on Performance and Carcass Quality

A study was conducted to evaluate early weaning of beef calves at 60-70 days of age on feedlot performance and carcass characteristics. One hundred twenty steer calves sired by either Simmental or Angus sires were weaned at an average age of 67 (early weaned, EW) or 147 (late weaned, LW) days. Calves were allotted to 16 feedlot pens by weaning treatment and sire breed at approximately 750-800 lb. EW calves were heavier (P < .05) in initial feedlot weight. There were no differences due to weaning age on daily gain, dry matter intake, feed efficiency or slaughter weights. Simmental steers required more days on feed than Angus steers (P < .05). Early-weaned calves had a higher percent intramuscular fat (5.7 vs. 5.1%), higher average marbling scores (Small78 vs. Small20, P < .05), a higher percentage of cattle grading average USDA Choice and higher (38% vs. 14%, P < .05) and a higher percentage of USDA Prime (10% vs. 0%, P < .05). These data confirm observations in previous studies that early weaning and placing calves on a higher grain diet improves marbling at slaughter. In this study, the effect was shown in calves weaned at an average of 67 days.

Antibiotic Susceptibility of Mycoplasma bovis Strains Recovered From Mycoplasmal Pneumonia and Arthritis in Feedlot Cattle

Mycoplasmal pneumonia and arthritis is a problem of increasing significance in Midwestern feedlots. The disease presentation cannot be prevented by vaccination or successfully treated with antimicrobials. Due to the reported difficulty in treating these outbreaks, in-vitro antimicrobial susceptibility was tested on isolates of Mycoplasma bovis recovered from cases of pneumonia or pneumonia and arthritis where the mycoplasma was involved as a causative agent. Using a broth microdilution method, 36 M. bovis isolates from cases of pneumonia and 9 from cases of pneumonia and arthritis were tested for susceptibility to antimicrobials currently used in cattle with respiratory disease (ampicillin, tilmycosin, spectinomycin, tylosin, lincomycin, tetracycline, ceftiofur, and erythromycin). Among the isolates from cases with pneumonia, resistance to more antimicrobials was shown in recent isolates than in isolates from earlier years. Tetracycline and lincomycin were the drugs of choice for these isolates, although 3 of 36 isolates were resistant to all drugs tested. Isolates from cases of pneumonia and arthritis were from recent accessions. A majority of these isolates (5/9) were resistant to all antimicrobials tested. Lincomycin, spectinomycin, and tetracycline were antibiotics usable with 4/9 of the isolates. Overall, the results indicate that antimicrobial therapy in cases of mycoplasmal feedlot pneumonia and arthritis may be unrewarding.

Investigation of the Potential Effects of Epizootic Hemorrhagic Disease Virus on Iowa Cattle

Epizootic hemorrhagic disease virus (EHDV), an arthropod-borne orbivirus, causes significant mortality in white-tailed deer and can also cause disease in cattle. Objectives of this preliminary investigation were 1) to survey cattle at auction markets to determine the prevalence of anti-EHDV antibodies in Iowa cattle, 2) to determine EHDV seroprevalence in herds in which clinical EHD had been diagnosed, and 3) to determine whether EHDV is associated with stillbirths and/or congenital anomalies in calves. There was a 15% seroprevalence in auction market cattle; positive cattle were from southern, central, and western Iowa. Herds in which clinical EHD had been diagnosed had >60% seroprevalence. Viremia was detected in both clinically affected and unaffected cattle during an EHD outbreak. EHDV exposure was not consistently associated with congenital anomalies. Although additional surveillance is warranted, EHDV is unlikely to have a significant effect on the reproductive health of Iowa cattle.

Live Cattle Futures and Options: How Have They Done?

Futures did reduce price risk. Hedging produced a higher minimum return and higher return at the 25th percentile (75% of the returns are better than this figure) than did the cash market. The 50th percentile, or median return, was higher for yearlings in the cash market than hedged cattle, and the calves had mixed results. Although the differences are not great, there have been months when the option strategies performed better than cash or futures, (i.e., January–April and September–October), and there are months when they did not fare well (i.e., June–August).

Estimating the Value of Source Verification in Iowa Feeder Cattle Markets

Source verification and pooling of feeder cattle into larger lots resulted in higher selling prices compared to more typical sales at a southern Iowa auction market. After higher prices due to larger lot sizes were accounted for, cattle that received a specified management program and were source verified as to origin received additional price premiums. The data do not distinguish between the value of the specific management program and the value of the source verification process. However, cow–calf producers participating in the program took home more money.

Profiting from the Cattle Cycle: Alternative Cow Herd Investment Strategies

Beef cow herd owners can benefit from incorporating price signals into their heifer retention decisions. Whereas a perfect forecast of calf prices over the productive life of the heifer added to the herd would be ideal, such information is not available. However, simple decision rules that incorporate current or recent prices and the knowledge that the cattle cycle likely will repeat itself can help producers improve their investment decisions. A dollar cost averaging strategy that retains the same dollar value of heifers each year and a rolling average value strategy that retains a 10-year average value of heifers out performed strategies that sought to maintain a constant herd size or a constant cash flow.

Estimating the Value of Source Verification in Iowa Feeder Cattle Markets

Source verification and pooling of feeder cattle into larger lots resulted in higher selling prices compared with more typical sales at a southern Iowa auction market. After accounting for higher prices due to larger lot sizes, cattle that received a specified management program and were source verified as to origin received additional price premiums. The data do not distinguish between the value of the specific management program and the value of the source verification process. However, cow-calf producers participating in the program took home more money.