Effects of Internal Parasite Infection at Feedlot Arrival on Performance and Carcass Characteristics in Beef Steers

The performance and carcass characteristics of 43 beef steers were evaluated relative to internal parasite burden at feedlot arrival. Despite being effectively dewormed at feedlot entry, cattle with more significant worm burdens on arrival had lesser body weights throughout the feeding period and tended to have more days on feed. Even with a tendency for more days on feed, more heavily infected cattle also tended to have lesser marbling scores, dressing percentages, KPH, and back fat. However, there were no differences in ADG throughout the finishing period, REA, yield grade, or HCW relative to initial worm burden. These data indicate that larger worm burdens at feedlot arrival can have long-term effects on body weight and carcass characteristics even when deworming procedures are successful. This information highlights the importance of internal parasite control during the grazing and growing period

Comparison of Ivermectin and Extended-release Eprinomectin Deworming Treatment on Stocker and Subsequent Feedlot Performance and Carcass Characteristics of Fall-born Angus Heifers

Severe parasite infections in beef cattle are sometimes associated with decreased growth and performance and clinical disease. Stocker cattle are exposed to many parasites and appropriate deworming strategies can help to minimize parasite burdens when cattle are on grass. Feedlot cattle are often dewormed at arrival and have minimal exposure to additional parasites once placed in the feedlot. The purpose of this study was to evaluate stocker and feedlot performance and carcass characteristics relative to treatment with deworming agents of varying durations of activity

Feeding and Economic Considerations for Baleage Use in Cow-calf Diets

Recent years of drought and suboptimal hay-making conditions have left many cattlemen in Iowa and much of the country with either reduced or poorer quality forage supplies, thus resulting in sharp forage price increases over the past 2 years. Feed costs in the cow-calf sector are often greater that 60% of total production costs, with a large proportion of that 60% derived from forage expenditures. Thus, evaluating harvested forage management practices and adopting new schemes that may increase forage quality, as well as reduce dry matter (DM) losses and feed wastage, are essential to minimizing wintering feed costs and maintaining profitability

Effects of Extended-release Eprinomectin on Cow/calf Performance and Reproductive Success in a Fall-calving Herd

This study evaluated the effects of extended-release eprinomectin on performance parameters and reproductive efficiency of fall-calving cows. Cows were treated with either a conventional, short duration dewormer (CONV) or an injectable extended-release eprinomectin (EPR). Change in body weight (BW) and average daily gain were greater in EPR cows compared to CONV treated cows. Pregnancy rates tended to be greater for EPR than CONV cows. Calves from dams treated with EPR were younger at weaning, but had greater weaning weights than calves from CONV dams. Results from this study indicate performance and reproductive advantages for dams treated with EPR as well as possible indirect performance advantages for calves whose dams were treated with EPR

Effects of Eprinomectin on Bull Reproductive Performance

Parasitic infections in cattle are known to negatively impact cattle performance. It has been demonstrated that anthelmintic treatment that reduces or eliminates worm load can positively influence cattle productivity by increasing a plethora of parameters including weight gain, reproductive efficiency, and carcass characteristics. While parasitic infections pose threats to all cattle, bulls have been found to be more susceptible than their female counterparts and tend to acquire higher worm loads more quickly. While an increased susceptibility in bulls is recognized, little research has been done to determine the effect of anthelmintic treatment on bull reproductive performance and semen quality. This study evaluated the effects of eprinomectin on performance parameters and reproductive function in bulls during the summer grazing and breeding season. We observed no differences in BW and BCS between treatment with either injectable eprinomectin or injectable doramectin. Likewise, semen and reproductive parameters including motility, morphology, scrotal circumference, and scrotal tone were not affected by treatment. Overall, both treatments effectively reduced internal parasite loads during the breeding season. Results from this study that eprinomectin does not negatively impact production or reproductive parameters in reproductively active bulls and is effective at reducing parasitic infection over the course of the breeding season

Use of Interactive Electronic Audience Response Tools (Clickers) to Evaluate Knowledge Gained in Extension Programming

Effectively measuring short-term impact, particularly a change in knowledge resulting from Extension programming, can prove to be challenging. Clicker-based technology, when used properly, is one alternative that may allow educators to better evaluate this aspect of the logic model. While the potential interface between clicker technology and Extension programming has been a topic of discussion, the successful use and stakeholder attitude towards such technology in an Extension setting is not well known. This article addresses this gap in understanding and provides an assessment of clicker use in Extension programming

Effects of Extended-release Eprinomectin on Replacement Heifer Performance and Reproductive Success

This study evaluated the effect of extended-release eprinomectin on production parameters and reproductive success of yearling fall replacement heifers. Heifers were treated with an ivermectin (CONV) or an injectable extended-release eprinomectin (EPR). There were no differences between treatments at initial body weight (BW). However, subsequent body weights taken 7 months and 12-months post-treatment demonstrated heavier body weight, greater overall weight gain and a greater average daily gain for heifers treated with EPR. Heifers treated with EPR had greater pregnancy rates to AI and greater overall pregnancy rates than CONV. Also, a greater proportion of EPR heifers calved in the first 21 days of the subsequent calving season. Results from this study indicate improved performance and greater reproductive success for replacement heifers treated with extended-release eprinomectin

Incidence of Ovulation to GnRH at Onset of 5-d CO-Synch + CIDR Protocol and Impact on Reproductive Responses

The objective of this study was to determine howresponse to GnRH at the onset of the 5-d CO-Synch +CIDR protocol (5dCO) affected estrous response, follicular dynamics, and pregnancy success to timed-AI (TAI) beefcows that had calved. On 359 cows, GnRH response at theonset of the synchronization protocol was 54.6%. Estrous response prior to TAI was greater in cows that failed to ovulate after GnRH administration than those that ovulated. However, dominant follicle diameter at TAI was not influenced by GnRH response. Timed-AI pregnancy rates were greater in cows that did not respond to GnRH (65.0%) than those that did (51.5%). These results cannot be interpreted as removing GnRH at the beginning of the 5dCO would affect TAI pregnancy responses. These results, however, warrant subsequent field studies to determine the necessity of GnRH administration at CIDR insert in the 5-d CO-Synch + CIDR protocol

Effect of Excess Dietary Crude Protein from Corn Gluten Meal or Soybean Meal on Reproductive Function of Beef Cows Consuming Low Quality Forage

Coproducts of the ethanol industry are a concentrated package of crude protein (CP) which can be fed to beef cows in conjunction with low quality forage to make economical diets that meets nutrient requirements. With this pairing, having excess dietary CP is likely; however the effects of these excessive CP diets on beef cow reproduction have not been made clear. In addition, the effects of excess dietary CP from feedstuffs that differ in rumen degradability are not known. In the present study, we studied the effects of diets containing 150% of metabolizable protein (MP) requirements from a moderately high (corn gluten meal) or low (soybean meal) rumen undegradable protein (RUP) fraction on reproductive function around the time of ovulation. We observed that excess dietary RUP enhanced dominant follicle growth and ovulatory parameters, while excess dietary rumen degradable protein (RDP) improved circulating progesterone concentration post ovulation. Based on these data, source of CP when fed to excess may have differential impacts on reproductive function in mature beef cows. However, the mechanisms by which these physiological alterations occur are unknown at this time. Thus, more research is warranted to elucidate how source and amount of CP, when supplemented in low quality forage-based diets, may influence reproductive function in beef cows

Adapting the 2016 National Academies of Sciences, Engineering and Medicine—Nutrient Requirements of Beef Cattle to BRaNDS Software—Considering Metabolizable Protein

The National Academies of Sciences, Engineering and Medicine - Nutrient Requirements of Beef Cattle (NASEM), formally referred to as the National Research Council (NRC), has long been the standard of formulation for beef cattle rations. However, the changes presented in the 8thEdition (2016) regarding the empirical method of formulation appear to only work well with cows and more mature stocker cattle consuming medium- to high-quality forage (51.5-64% TDN) when the microbial efficiency of converting diet TDN to microbial protein are adjusted from the current recommendation back to previously published efficiencies