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Though much effort has been made to characterize the in vivo (IV) and in situ (IS) dry matter digestibility (DMD) of southeastern forages, there is a lack of information identifying methods that best represent the in vivo digestibility of these forages. Thus, the objective of our study was to compare IV and IS methods to determine which technique best represents the in vivo DMD of four bermudagrass (Cynodon dactylon [L.] Pers.) cul-tivars. In an IV experiment, ruminally fistulated heifers (n = 4) were randomly assigned to one of four bermudagrass cultivars (Coastal [COS], Russell [RUS], Tifton 44 [T44], or Tifton 85 [T85]) for four 30-d in vivo periods (21-d adaptation and 9-d collection) in a Latin square design. On d 28 of each period, rumen fluid was collected 4 h post-feeding for an accompanying IV experiment using a completely randomized design with a 4 x 2 factorial treatment structure. Factors in the IV experiment included bermudagrass cultivar (COS, RUS, T44, and T85) and digestibility method (Tilley and Terry [TT] or Goering and Van Soest [GVS]). On d 31 of in vivo periods 3 and 5, an accompanying IS experiment was conducted as a randomized complete block design with three treatment factors (in vivo diet [previous described], bermudagrass cultivar [previously described], and incubation timepoint [0, 0.25, 0.50, 0.75, 1, 2, 3, 4, 8, 12, 16, 20, 24, 48, 72, 96, 120, 144, and 168 h]). Correlations were computed between in vivo DM disappearance and each of the IV (TT and GVS) and IS (24, 48, and 72 h) methods. Regressions were calculated for each of the individual IV and IS measurements, and a stepwise regression was used to determine the predictive value of linear combinations of the measurements. None of the IV or IS DMD values were correlated with in vivo DMD (P ≥ 0.18). Individual IV and IS DMD values did not yield significant models through linear regression (P ≥ 0.18), though the best model (based on AIC) was TT IVDMD (r² = 0.09; P = 0.26). Stepwise regression revealed that there was no linear combination of IV or IS DMD that improved prediction beyond single predictor models. While both IV and IS experiments remain viable tools to screen forages and make relative comparisons, results from this experiment are interpreted to mean that neither of these methods is suitable for prediction of in vivo performance. [ABSTRACT FROM AUTHOR]

Food production globally must double to meet demand by 2050. Demand for animal protein, coupled with reductions in grazing lands, intensifies a need for greater efficiency in beef production. Beef production relies on farms and ranches raising calves for later sale. Our goal is preparation of fellows which are crosstrained to gain inter- and intra-disciplinary knowledge and experiences, capable of bringing creative solutions to critical challenges, within the industry. Applicants were solicited via advertisements, list-serve networks, and recruitment webinars. Selection was guided by a rubric which included interviews and essays above a basic application. Through coaching/mentorship and leadership training, fellows were charged with creation of Individualized Development/Experience Plans (IDP) involving learning community dynamics, common experiences, shared/collaborative research, professional leadership & empowerment, stakeholder engagement, scholarly immersion, translational communication skills and classroom teaching. Fellows increased competencies in critical-thinking fundamentals of environmental/production sustainability emphasizing forages, beef systems, economics and more. Immersion experiences with stakeholders utilized a "design thinking" framework promoting complex creative problem-solving. Fellows were immersed in an 'Experiential Learning Cycle' via comprehensive planning and execution of a high-impact experience in a regional outreach stockman and stewardship event. The ANSC-NNF program creates a pipeline to industry and extension careers with graduates who understand modern challenges within production agriculture and specifically beef production. Assessments indicate the program permeated the entire graduate program within the department of animal sciences and in addition to thesis research, Fellows gained knowledge through leadership, process management, systems & sustainability and obtained skills and abilities including professional certifications. The department has initiated recruitment of a second cohort of six master's-level Fellows for 2023-2025. [ABSTRACT FROM AUTHOR]

Research in growth and development, accumulation of lean, and fat metabolism in farm animals was gaining attention principally from a carcass perspective by meat scientists and animal nutritionists about a century ago. Under the auspices of the USDA Cooperative State Research Service, State Agricultural Experiment Stations, and the Land Grant University system, researchers from various universities embarked on forming combined regional research projects (across states) with unifying specific aims. In the North Central region, this included states in the upper and lower Mid-West region. For those interested in improving production and eating quality of meats, initially a single multistate committee was formed in the North Central region which was active for many years. However, these efforts were later split into two committees with one addressing lipids and the other muscle biology. Herein we reviewed research of workers in the North Central region in the 1940s and 1950s and to a limited extent in the 2000s on meat animal's lipid metabolism. We further reviewed the history of meat animal carcass composition research and the influence of the Word War II (WWII) period on porcine carcass composition. The development and utilization of adipocyte cellularity research methodology in meat animals was demonstrated. The history of the progression of adipose tissue metabolism research in meat animals was also reviewed. Finally, the history of research on lipid deposition in muscle that ultimately precipitated the expanded marbling and the intramuscular research was delineated. By the 1970s, great interest had emerged on how to curtail excessive fat deposition in meat-producing animals. Thus, for some segments of the animal lipid metabolism community, the focus then shifted to exploring the processes of lipogenesis and lipolysis in farm animals. These efforts morphed into research efforts in fat cell biology and cellularity. Today adipocyte biology is studied by many in the biomedical and agricultural-life sciences communities. In this article, we present a history of this research and notable achievements up to the 1980s. Herein we revisit these research efforts and results that have become an important knowledge base for growth and development, nutrition, and meat science research. [ABSTRACT FROM AUTHOR]

While much effort has been devoted to both the characterization of ruminal fermentation dynamics and the evaluation of bermudagrass production, independently, there is a lack of information regarding ruminal digestive kinetics using beef cattle in southern forage systems. Thus, the objective of our study was to evaluate in situ digestive kinetics of four bermudagrass (Cynodon dactylon [L.] Pers.) cultivars in heifers consuming typical southern forages. (Coastal, Tifton 44, Tifton 85, and Russell). Ruminally fistulated heifers (n = 4) were assigned randomly to one of four bermudagrass cultivars (Coastal [COS], Russell [RUS], Tifton 44 [T44], or Tifton 85 [T85]) for four 30-d in vivo periods (21-d adaptation and 9-d collection). On d 31 of periods 2 and 3, an in-situ experiment was conducted as a randomized complete block design with a 3-factor factorial treatment structure. The first factor (n = 4) was diet consumed by the animal (described above). The second factor (n = 4) was the incubated forage (same cultivars as the in vivo experiment). The third factor was incubation timepoint (n = 19; 0, 0.25, 0.50, 0.75, 1, 2, 3, 4, 8, 12, 16, 20, 24, 48, 72, 96, 120, 144, and 168 h). Four in situ bags were incubated in each animal at each timepoint; two were used for NDF, ADF, and ADL, and two were used for CP determination. Data were analyzed using SAS v. 9.4. There was a decreased (P < 0.05) potentially degradable fraction from COS (30.0%) compared with T85 (55.1%), T44 (48.1%), or RUS (47.1%). Similarly, COS presented the greatest (P < 0.05) undegradable fraction (37.0%) and T85 the least (15.9%), with RUS and T44 intermediate (25.0 and 21.9%, respectively). There was no effect of bermudagrass cultivar, however, on the rate constant of digestion (0.94%/h; P = 0.26) or lag time (3.2 h; P = 0.38). A visual appraisal of the degradation curve suggests that the asymptote of digestion was not reached at the measured 168 h. Results are interpreted to mean that T44 is the preferable bermudagrass cultivar, followed by T85 and RUS, while COS is the least favorable. Further, given the lack of visible asymptote, we speculate that bermudagrass likely passes the rumen before full digestion is realized. [ABSTRACT FROM AUTHOR]

Nitrogen Deficits in Aroclor 1254-Treated Rats. EBNER, K. V., BERGEN, W. G., and BRASELTON, W. E., Jr. (1987). . , 89–96. Nitrogen balance and the efficiency of retaining assimilated dietary nitrogen (biological value) were evaluated in Aroclor 1254-treated (ARO) rats and in vehicle-treated, pair-fed (PF) and -fed (AF) rats (150–190 g). ARO-treated rats (300 mg/kg/day, po on 4 consecutive days) lost weight and consumed less chow than the AF group while the weight of the PF rats was not different from those of either the ARO or AF groups. The nitrogen balance and the biological value for the ARO rats were also significantly less than those of the AF rats whereas the PF controls were not different. The ingested calories (expressed in kcal/(kg body wt)) by the ARO and PF rats were equal, but were less than those of the AF group. The ARO and PF groups excreted the same amounts of fecal nitrogen which were less than the fecal nitrogen excretion by the AF rats. The absorbed fraction of the ingested nitrogen was the same among all groups, which indicated that the digestibility and absorption of the dietary nitrogen were not changed. By contrast, the ARO group excreted the same amount of urinary nitrogen and urea as AF rats while the PF group excreted significantly less urinary nitrogen than the latter controls. Thus, the loss of nitrogen by the ARO group was attributed to increased excretion of urinary nitrogen, most likely as urea, in relation to the nitrogen intake. The nitrogen retention and balance in rats with ARO exposure are similar to the response in rats fed a diet of low biological value except that the influence of ARO on nitrogen metabolism occurred during the postabsorption phase. [ABSTRACT FROM PUBLISHER]