Our objective was to investigate the effects of administering the nonsteroidal anti-inflammatory drug meloxicam (MEL) before transport on various indicators of protein metabolism and growth performance over the first 96 h after transport in Jersey calves. Calves (age ± SD; 2 ± 1 d) sourced from a commercial farm were randomly administered, at 1 mg/kg of body weight, either meloxicam (MEL; n = 11) or a whey protein placebo (CON; n = 10) orally before transport to a calf facility (669 km; 8.5-h road trip). Calves were weighed and rectal temperature was recorded before departure (0 h), on arrival (8.5 h), and 96 h after arrival. Blood was collected at the same time as calves were weighed, and samples were analyzed for total protein (0-h sample), cortisol (0-and 8.5-h samples), haptoglobin (0-and 96-h samples), and amino acids, 3-methylhistidine, and urea-N (96 h). Milk replacer (MR) intake was recorded on arrival and over the next 4 d.

Bacterial cultures, enzymes and yeast derived feed additives are often included in commercial dairy rations due to their effects on ruminal fermentation. However, the effects of these additives when fed together are not well understood. The objective of this study was to evaluate the changes in ruminal fermentation when a dairy ration is supplemented with combinations of bacterial probiotics, enzymes and yeast. Our hypotheses were that ruminal fermentation would be altered, indicated through changes in volatile fatty acid profile and nutrient digestibility, with inclusion of: (1) an additive, (2) yeast and (3) increasing additive doses. Treatments were randomly assigned to 8 fermenters in a replicated 4 × 4 Latin square with four 10 d experimental periods, consisting of 7 d for diet adaptation and 3 d for sample collection. Basal diets contained 52:48 forage:concentrate and fermenters were fed 106 g of dry matter per day divided equally between 2 feeding times. Treatments were: control (CTRL, without additives); bacterial culture/enzyme blend (EB, 1.7 mg per day); bacterial culture/enzyme blend with a blend of live yeast and yeast culture (EBY, 49.76 mg per day); and double dose of the EBY treatment (2X, 99.53 mg per day). The bacterial culture/enzyme blend contained five strains of probiotics (Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus lichenformis, Bacillus subtillis, and Enterococcus faecium) and three enzymes (amylase, hemicellulase, and xylanase). On d 8-10, samples were collected for pH, redox, volatile fatty acids, lactate, ammonia N and digestibility measurements. Statistical analysis was performed using the GLIMMIX procedure of SAS. Repeated measures were used for pH, redox, VFA, NH3-N and lactate kinetics data. Orthogonal contrasts were used to test the effect of: (1) additives, ADD (CTRL vs EB, EBY and 2X); (2) yeast, YEAST (EB vs EBY and 2X); and (3) dose, DOSE (EBY vs 2X). No effects (p > 0.05) were observed for pH, redox, NH3-N, acetate, isobutyrate, valerate, total VFA, acetate:propionate, nutrient digestibility or N utilization. Within the 24h pool, the molar proportion of butyrate increased (p = 0.03) with the inclusion of additives when compared to the control while the molar proportion of propionate tended to decrease (p = 0.07). In conclusion, inclusion of bacterial cultures, enzymes and yeast to the diet increased butyrate concentration; but did not result in major changes in ruminal fermentation.

Corn is a feedstuff commonly fed to dairy cows as a source of energy. The objective of this study was to evaluate whether partially replacing dietary corn with molasses or condensed whey permeate, in lactating dairy cow diets in a dual-flow continuous culture system, can maintain nutrient digestibility by ruminal microorganisms. Furthermore, this study evaluated whether treating condensed whey permeate before feeding could aid the fermentation of the condensed whey permeate in the rumen. Eight fermentors were used in a 4 × 4 replicated Latin square with 4 periods of 10 d each. The control diet (CON) was formulated with corn grain, and the other diets were formulated by replacing corn grain with either sugarcane molasses (MOL), condensed whey permeate (CWP), or treated condensed whey permeate (TCWP). Diets were formulated by replacing 4% of the diet dry matter (DM) in the form of starch from corn with sugars from the byproducts. Sugars were defined as water-soluble carbohydrates (WSC) in the rations. The fermentors were fed 52 g of DM twice daily of diets containing 17% crude protein, 28% neutral detergent fiber, and 45% nonfiber carbohydrates. Liquid treatments were pipetted into each fermentor. After 7 d of adaptation, samples were collected for analyses of volatile fatty acids (VFA), lactate, and ammonia, and fermentors' pH were measured at time points after the morning feeding for 3 d. Pooled samples from effluent containers were collected for similar analyses, nutrient flow, and N metabolism. Data were statistically ana-lyzed using Proc MIXED of SAS version 9.4 (SAS Institute Inc.); fixed effects included treatment and time, and random effects included fermentor, period, and square. The interaction of treatment and time was included for the kinetics samples. The TCWP and MOL treatments maintained greater fermentor pH compared with CWP. Total VFA concentration was increased in CWP compared with MOL. The acetate: propionate ratio was increased in TCWP compared with CON, due to tendencies of increased acetate molar proportion and decreased propionate molar proportion in TCWP. Lactate concentration was increased in MOL. Digestibility of WSC was increased in the diets that replaced corn with byproducts. The partial replacement of 4% of DM from corn starch with the sugars in byproducts had minimal effects on ruminal microbial fermentation and increased pH. Treated CWP had similar effects to molasses.

In order to decrease the time and cost of experiments as well as the use of animals in nutrition research, in vitro methodologies have become more commonplace in the field of ruminant nutrition. Therefore, the objectives of this review are i) describe the development of different in vitro methodologies, ii) discuss the application, utilization, and advantages of in vitro methodologies, iii) discuss shortcomings of in vitro methodologies, and iv) describe potential developments that may be able to improve in vitro methods. Having been used for decades, some in vitro methodologies such as pure, batch, and continuous cultures have been very well documented and utilized to investigate a wide array of different aspects of nutrition, including the effects of different dietary compositions, individual fermentation end products, and impacts on the microbiome of the rumen. However, both batch and pure cultures can result in a build-up of end products that may inhibit fermentation, as they culture ruminal contents or defined strains of bacteria, respectfully. Continuous culture; however, allows for the removal of end products but, similar to pure and batch cultures, is applicable only to ruminal fermentation and cannot provide information regarding intestinal digestion and bioavailability. This information for in vitro can only be provided using an assay designed for total tract digestibility, which is the three-step procedure (TSP). The TSP may be improved by coupling it with cell culture in order to investigate absorption of nutrients in both the ruminal and intestinal phases of the methodology; however, the TSP needs further development in order to investigate all nutrients and the methodologies available for cell culture are still relatively new to ruminant nutrition. Therefore, while in vitro methodologies provide useful data into the field of ruminant nutrition without the continuous use of animals, there is still much work to be done in order to improve the methodologies to further apply them.

Teff (Eragrostis tef cv. Moxie), a warm-season annual grass, could be an excellent forage for beef cattle. However, there is limited information on its nutritive value to cattle when harvested at different stages of maturity. Thus, the objective of this research was to determine the effect of feeding teff hay harvested at the boot (BT), early-heading (EH), or late-heading (LH) stages of maturity on nutrient intake, ruminal fermentation characteristics, omasal nutrient flow, and N utilization in beef cattle. Six ruminally cannulated beef heifers (mean initial BW ± SD, 476 ± 32.6) were used in a replicated 3 × 3 Latin square design with 28-d periods (18 d for adaptation and 10 d for measurements). Dry matter intake was measured daily. Indwelling pH loggers were used to measure ruminal pH from days 21 to 28. Ruminal fluid and omasal digesta were collected from days 26 to 28 to determine fermentation characteristics and omasal nutrient flow. Fecal and urine samples to quantify N excretion were also collected (days 26 to 28). Blood samples for plasma urea-N (PUN) determination were collected 3 h post-feeding on day 28. There were no changes (P > 0.28) in the ADF or NDF content of teff with advancing maturity, but indigestible NDF increased (P < 0.01) with increasing maturity. Maturity had no effect (P ≥ 0.14) on DMI, and ruminal total short-chain fatty acid (SCFA) concentration, pH, digestibility, and outflow of DM, OM, NDF, ADF, and CP. However, the CP content of BT hay was greater (P < 0.01) than for EH and LH hay (18.1, 14.1, and 11.5%, respectively, DM basis), and this resulted in the higher CP intake (P < 0.01) for heifers fed the BT than the EH and LH hay. Consequently, ruminal ammonia-N (NH3-N) concentration was greater (P < 0.01) for heifers fed BT than EH and LH hay, thereby possibly explaining the tendency for a decrease (P = 0.08) in PUN concentration, and a decrease (P < 0.01) in the excretion of total N, urine N, and urea-N (UUN) with advancing maturity. However, fecal N excretion (g/d) did not differ (P = 0.76). In conclusion, despite a decrease in CP intake and ruminal NH3-N concentration, feeding beef heifers EH and LH compared to BT teff hay did not compromise ruminal digestion and outflow of DM, OM, NDF, ADF, and CP, and microbial protein synthesis. Advancing maturity in teff hay also resulted in a decrease in the excretion of total N and urine N and UUN when fed to cattle.