Effects of Premortem Stress on Heat Shock Protein Abundance, Oxidation, and Color in the Longissimus lumborum of Holstein Steers Following Harvest

Consumers consider tenderness and steak color to be two important attributes associated with meat quality. However, inconsistencies in both tenderness and steak color remain despite similar production practices of beef cattle. Stressful events before harvest may impact meat quality by initiating certain pathways such as abundance of heat shock proteins (HSP) and oxidation within the skeletal muscle. Heat shock proteins have been associated with tenderness while oxidation may affect steak color and flavor. In this study, 40 Holstein steers were administered adrenocorticotrophic hormone (ACTH) to mimic a stressful event before harvest. Animals were harvested at different times following the ACTH challenge (2 h, 12 h, 24 h, and 48 h; n=10). In addition, animals were grouped based on cortisol response 0.5 h after initiation of the ACTH challenge (lowest, lower, higher, and highest; n=10) because initial serum cortisol concentrations were variable following the challenge. Skeletal muscle tissues were collected from the longissimus lumborum (LL) before the ACTH challenge, at harvest, and after 14 d of aging. Blood samples were also collected. We investigated how time of harvest and cortisol response affected HSP abundance, tenderness, oxidation, and steak color. Time of harvest affected the relative abundance of one of three HSP analyzed, Phosphorylated-HSPβ1 (P-HSPβ1). The abundance of P-HSPβ1 was increased at harvest in animals harvested 48 h after the ACTH challenge, while after 14 d of aging animals that were harvested 24 h after the ACTH challenge had increased abundance of P-HSPβ1. Additionally, time of harvest affected tenderness assessed by the protein troponin I, a regulatory protein in the muscle, and myofibrillar fragmentation index (MFI). Animals that were harvested 24 h after the ACTH challenge had increased abundance of troponin at harvest and increased MFI after 14 d of aging. Both time of harvest and cortisol response affected oxidation assessed by DJ1, protein which is a marker of oxidation, and thiobarbituric acid reactive substances (TBARS). Animals that were harvested 24 h after the ACTH challenge had increased abundance of DJ1 and increased concentration of TBARS in the serum. In addition, steak color was affected by both time of harvest and cortisol response. Animals that were harvested 24 h and 48 h after the ACTH challenge had yellower and redder steaks than animals harvested 2 h and 12 h after the challenge. These finding indicate that time of harvest and cortisol response following a stressful event impacts meat quality, however more research is needed to fully understand the impacts of premortem stress on meat quality

Implementing Bos Indicus-Influenced Cattle in Utah for Hybrid Vigor

Crossbreeding is a tool that cattle producers have used for decades. Hybrid vigor is one of the products of crossing breeding. One way to maximize hybrid vigor is by introducing Bos indicus genetics in a herd. Santa Gertrudis cattle are a great option for introducing Bos indicus genetics

Heat Stress and Reproduction in Beef Cattle

Reproduction could be considered the most important production trait on a cow-calf operation. Economic outputs are sustained when cattle rebreed and calve every year in a timely manner. However, when cattle are unable to rebreed efficiently, profits may decrease for producers. It is well known that heat stress can negatively impact reproduction in cattle (Jordan, 2003). The Intermountain West has been impacted by drought and increasing temperatures, both of which can impact reproduction rates in cattle. This fact sheet helps producers understand the consequences of heat stress on cattle reproduction and how they can manage reproduction during increasing temperatures

Raising a Bottle-Fed Calf on a Cow/Calf Operation

Having bottle-fed calves on the ranch is common for beef producers. The most likely scenarios are a cow has died, a cow isn’t giving enough milk, or a twin has been rejected. All these scenarios are likely to happen, which results in an orphan calf. Bottle-feeding a calf is straightforward; however, there are limited resources, specifically for beef producers, looking for bottle-fed calf management strategies. When bottle-feeding a beef calf, there are some things to consider, such as feeding colostrum, selecting and using milk replacers, and weaning the calf. Many of the resources on bottle-calf management come from the dairy industry; however, beef producers can tailor dairy industry strategies to fit their own operation

Drought Mitigation for Cow/Calf Producers: Depopulation Strategies

Drought is a recurring event faced by many cow/calf producers across the nation. As drought events increase in their severity, it is important for cattle producers to have a management plan to mitigate the economic effects of drought. Two of the most common strategies for mitigating the effects of drought include buying additional feed and depopulating a portion of the herd. This fact sheet reviews strategies that will guide the decision-making process to cull cattle during drought

The Benefits of Growth-Promoting Implants for Beef Cattle

Growth-promoting implants have been used in the cattle industry for decades. Their benefits allow cattle producers to become more sustainable by decreasing the amount of resources used. Resources such as water and land are decreased when using growth-promoting implants in beef cattle

Evaluating Alternative Feed Sources During Drought

During years of drought, it is important to critically evaluate alternative feed sources available for cattle. The traditional method for sustaining a herd through a drought is feeding extra stored forage to compensate for decreased forage production or decreased forage quality available on rangelands and pastures due to drought conditions. However, hay prices rise substantially, and availability decreases due to irrigation water limitations and increased demand from livestock producers. This fact sheet will evaluate why hay prices rise and what alternatives are available to compensate for forage reductions during drought

Effects of Feeding a Novel Alfalfa Leaf Pellet Product (ProLEAF MAX) and Alfalfa Stems (ProFiber Plus) on Performance in the Feedlot and Carcass Quality of Beef Steers

Alfalfa is often included in the diets of beef animals; however, the nutrient content of alfalfa is variable depending on the region in which it is grown, climate, soil, and many other factors. The leaf portion of alfalfa has a less variable nutrient composition than the stem portion of the plant. The variability that is present in the alfalfa plant can make the development of total mixed rations of consistent nutrient content difficult. As such, the purpose of this study was to determine how the inclusion of fractionated alfalfa leaves and alfalfa stems impacts performance and carcass quality of finishing beef steers. Twenty-four steers were allocated to one of three treatments: a control group fed a typical finishing diet with alfalfa as the forage (CON; n = 8), a typical diet that replaced alfalfa with fractionated alfalfa leaf pellets and alfalfa stems (ProLEAF MAX™ + ProFiber Plus™; PLM+PFP; n = 8), or a typical diet that replaced alfalfa with alfalfa stems (PFP; n = 8) for 63 days. Steers were fed individually once daily, weighed every 14 days and ultrasound images were collected every 28 days. At the end of the feeding trial, steers were harvested at a commercial facility and carcass data was obtained. Analysis of dry matter intake demonstrated that steers receiving the PFP and CON diets consumed more feed (P \u3c 0.001) than steers consuming the PLM+PFP diet. Steers receiving the PLM+PFP diet gained less (P \u3c 0.001) weight than the steers receiving the other two dietary treatments. No differences (P \u3e 0.10) in feed efficiency or carcass characteristics were observed. Steers receiving the PFP diet had improved (P = 0.016) cost of gain ($0.93 per kg) when compared with steers receiving PLM+PFP ($1.08 per kg) diet. Overall, our findings demonstrate that the inclusion of PFP in place of alfalfa hay in a finishing diet has the potential to improve cost of gain, without negatively affecting growth, performance, or carcass characteristics of finishing feedlot steers