Objective Our objectives were to determine price dif-ferences between (1) dairy bull calves and beef-dairy-cross bull calves, (2) dairy bull calves and beef-dairy-cross heifer calves, and (3) beef-dairy-cross bull calves and beef-dairy-cross heifer calves. Materials and Methods Three auction reports con-taining data of beef-dairy-cross bull calves, beef-dairy-cross heifer calves, and dairy (primarily Holstein) bull calves sold in Kentucky and Pennsylvania from 2020 through 2025 were analyzed for yearly price differences between each breed × sex contemporary (n = 3) and location. Data available from the Pennsylvania auction were separated by feeder calf grade, with Number 1 and Number 2 calf data included and Number 3 and Number 4 calf data excluded from the analysis. Results and Discussion Across all 3 reports beef-dairy-cross bull calves demanded a greater average price ($/head) compared with dairy bull calves across all years studied, with the greatest price difference realized in 2025. However, with average mean prices increasing from 2020 to 2025, the percentage difference between the price of beef-dairy-cross bull calves and dairy bull calves decreased from 282% in 2020 and settled at 29% to 38% in 2025. Beef-dairy-cross heifer calves followed similar trends, with price premiums for the beef-dairy-cross animals increas-ing over the study period in absolute terms but decreas-ing from highs of 239% in 2020 to 17% to 32% in 2025. Beef-dairy-cross bull calves demanded a greater average price compared with beef-dairy-cross heifer calves across most years. When comparing beef-dairy-cross heifer calves and beef-dairy-cross bull calves, they had smaller price differences, with percentage differences being 4% to 11% in 2025. Implications and Applications Beef-dairy-cross bull calves have demanded a premium price compared with dairy bull calves and beef-dairy-cross heifer calves over the last 6 yr; however, the percentage difference has decreased in recent years. This analysis used the limited data avail-able, but more frequent and robust data are needed for a deeper analysis.
Objective Our objective was to evaluate the effects of supplementing preweaning dairy calves with smectite (montmorillonite bentonite clay) on serum immunoglobu-lin G (IgG), morbidity, and mortality. Materials and Methods Holstein and Jersey female calves were assigned to control (CON; force-fed 50 mL of water; n = 100) or smectite supplementation (SMECT; force-fed a paste made of 2.5 g of smectite and 5 mL of water followed by 50 mL of water; n = 100) daily from 1 (after colostrum feeding) to 10 d of age. Jugular blood samples were collected at d 1, 4, 8, 12, and 16 of age for determination of serum total protein, IgG, and blood he-matocrit from 44 calves. Researchers assessed fecal consis-tency, appetite, and respiratory disease daily up to 20 d of age. Calves’ therapeutic treatment and mortality records were collected up to 30 d of age. Results and Discussion Serum IgG concentrations tended to be greater for SMECT compared with CON calves during the supplementation period (22.0 ± 2.07 vs. 17.0 ± 1.98 g/L). Serum total protein and blood hemato-crit were similar among SMECT and CON calves. No ef-fects were detected on health and therapeutic treatments. However, mortality within 1 mo of age (3% vs. 8%) and risk of death tended to be less for SMECT compared with CON calves (risk ratio = 0.37; 95% CI = 0.10 to 1.32). Implications and Applications Low-dose smectite supplementation may help to maintain passive immunity while supplemented and reduce mortality within 1 mo of age.
Objective This 3-yr study evaluated the suitability of 2 varieties (Taza and Bunker) of triticale silage versus barley silage in beef backgrounding systems. Materials and Methods The experiment assessed forage yield and quality, steer performance, feed sort-ing, and economic outcomes. Fall-weaned crossbred steer calves were used in the study, 402 in 2016 (308 ± 22 kg), 238 in 2017 (335 ± 23 kg), and 299 in 2018 (316 ± 18 kg). Animals were stratified by BW and randomly allo-cated to 1 of 3 isonitrogenous, isocaloric TMR diets (n = 4 replications per diet each year). Feedlot performance data were analyzed using a linear mixed model assuming a completely randomized design. Results and Discussion Across years, Bunker and Taza triticale had a greater forage yield (6,749 and 6,592 kg of DM/ha, respectively) than barley (6,008 kg of DM/ ha). Barley silage contained less ADF, NDF, and lignin and more starch and Ca, with a tendency for greater TDN, whereas CP did not differ. No differences in steer performance (DMI, ADG, feed efficiency) or feed sorting were observed. Although the differences were not signifi-cant, numerical feeding cost was lowest for Taza triticale ($1.11/head per day), whereas Bunker triticale and barley ($1.15/head per day) were similar, and numerical cost of gains were $0.78/kg, $0.79/kg, and $0.77/kg, respectively. Implications and Applications Overall, triticale silages supported comparable steer growth and feeding costs to barley silage, suggesting that Taza and Bunker are viable alternatives for beef backgrounding systems in western Canada.
Objective Our objective was to evaluate the effects of different inclusion levels of calcium propionate (CaPr) in a protein supplement on growth performance, feed efficien-cy, body fat reserves, and economic return of replacement beef heifers managed under dry-season conditions and fed low-quality forage. Materials and Methods Forty full-blood Beefmas-ter heifers (~334 kg of BW) were randomly assigned to receive 0, 20, 40, or 60 g of CaPr/heifer daily for 42 d in a completely randomized design. Heifers were individually housed and fed a protein supplement (0.84 kg/d; 48.5% CP) plus ground corn stover offered ad libitum. Body weight and feed intake were recorded every 14 d, body fat reserves were assessed by ultrasound, and an economic evaluation based on feed costs was conducted. Results and Discussion Low-to-moderate CaPr in-clusion (20 to 40 g/d) improved BW gain and feed efficien-cy, reduced residual feed intake, and increased rump-fat thickness without affecting rib-fat thickness or longissimus lumborum area. In contrast, the highest dose (60 g/d) at-tenuated productive responses. Inclusion of 20 to 40 g/d increased income over feed costs and reduced cost of gain, whereas 60 g/d increased feed costs without productive benefit. Implications and Applications Supplementation with CaPr at 20 g/heifer per day (effective range 20 to 40 g/d) represents a practical strategy to support positive energy balance and body fat reserve accretion in dry-season beef systems relying on low-quality forage. Under these conditions, CaPr supplementation can improve growth performance, feed efficiency, and economic return without the negative associative effects commonly observed with cereal grain supplementation.
Objective This study aimed to evaluate forage pro-duction and performance of meat lambs grazing differ-ent forage cultivars during the dry season in the Brazilian Cerrado biome. Materials and Methods A randomized block design was used with 5 cultivars: Marandu, BRS Ipyporã, BRS Paiaguás, BRS Quênia, and BRS Tamani, under continu-ous stocking, with variable stocking rates. Lambs of mixed breed were used and received daily protein supplementa-tion at 1% of BW. Results and Discussion The greatest forage mass was observed in the BRS Tamani cultivar, 4,225 kg of DM/ha. The greatest forage accumulation rates were ob-served in the Marandu and BRS Tamani cultivars (14.4 and 14.9 kg of DM/ha per day, respectively). In contrast, the least value was observed in the BRS Ipyporã cultivar, 2.6 kg of DM/ha per day. The Marandu cultivar presented the greatest live/dead ratio of approximately 1.13. The chemical composition of the leaves of the Marandu culti-var presents a greater fiber content (NDF and ADF) and a lesser CP content. The BRS Ipyporã cultivar presented a greater CP content and a lesser fibrous content (NDF, ADF, and cellulose) in the simulated grazing material. The Marandu cultivar presents a greater stocking rate and a greater gain per area, 61% greater than the average of the other cultivars. Implications and Applications These results dem-onstrate that Marandu is the most suitable cultivar for lamb meat production during the dry season in the Cer-rado. Selecting appropriate forage cultivars can enhance lamb production efficiency and sustainability under tropi-cal, dry conditions.
Purpose The purpose of this review is to document the events that led to the discovery and development of the utility of monensin for improving feed efficiency in beef cattle. Monensin development is an example of an internally funded commercial research program whose objective was to discover and develop a product profit-able for the company as well as its customers. The pro-gram was justified on the market potential of the hoped-for product and, during the process, was subjected to numerous reviews. This review also illustrates all the research work necessary to obtain approval for product use, by agencies such as the US Food and Drug Admin-istration. Sources The sources for this article include the per-sonal records and observations of the authors, who were principally responsible for this discovery and development, peer-reviewed scientific literature, abstracts from scientific meetings, academic technical reports and company re-ports, and symposia. Synthesis This discovery of the utility of monensin in ruminants by Eli Lilly & Co. (Lilly) scientists was not the result of serendipity, but the result of a designed pro-gram. The goal of this program was 2-fold—first, to design a test system to find compounds that would modify ru-men VFA production, and second, to determine whether VFA production changes would improve feed efficiency in ruminants. Neither of these effects had been previously observed. Before monensin the only practical way to mod-ify VFA production was through ration change. This was not the result of a large corporate research program, but one that resulted from use of redirected limited resources. Once the activity of monensin in in vitro and in vivo tests was recognized, the development of monensin for cattle proceeded rapidly under the direction of a multidiscipline research team with unlimited resources. The final approval of the use of monensin in cattle was the result of the timely efforts of a large number of Lilly and academic scientists. Conclusions and Applications Monensin was ap-proved for inclusion in beef cattle rations 50 yr ago. It is currently (2026) used in an estimated 90% of US feedlot cattle and 70% of the US dairy cows. It is now used in 26 different countries, with 14 different applications. The effects of monensin on all aspects of ruminant physiology are estimated to be the subject of about 22,600 (Google Scholar, search for monensin and ruminants) scientific pa-pers and technical reports.
Objectives Our objectives were to evaluate the man-agement strategies of supplementation with extruded dried distillers grains cubes (DDG) and use of a growth-promoting implant on performance of growing steers graz-ing native range over 2 yr. Materials and Methods In Exp. 1 we compared (n = 140 steers per year; BW = 239 ± 21 kg) positive con-trol (PC): late-summer supplementation with 1.13 kg of DDG/d (as-fed basis) and stocking at 2.4 ha/steer; and high supplement (HS): DDG at 0.75% (2.1 kg as fed/d) of BW all summer with a 1.6 ha/steer stocking rate. In Exp. 2 we compared (n = 125 steers per year; BW = 225 ± 23 kg) negative control (NC): no supplement and stocking at 2.0 ha/steer; PC: late-summer supplementation with 0.91 kg of DDG as fed per day and stocking at 2.0 ha/ steer; and HS with stocking at 1.4 ha/steer. Before graz-ing, steers were implanted with a trenbolone acetate–es-tradiol (TBA/E) combination in Exp. 1 and progesterone and estradiol (PG/E) implant in Exp. 2. In mid-summer, one-third of steers in each pasture were either not reim-planted or reimplanted with TBA/E or PG/E. Economic returns were estimated using partial budgeting. Data from each experiment were analyzed using PROC MIXED in SAS 9.4 (SAS Institute Inc., Cary, NC) as a split-plot experiment. Results and Discussion Forage biomass and nutri-tive quality did not differ among treatments at any sam-pling date. The HS treatment increased early summer and overall ADG at both locations, but late-season ADG did not differ between PC and HS. The HS treatment pro-duced the greatest BW gain per hectare and system net returns because the greater supplementation rate support-ed both increased stocking rate and greater season-long ADG. Mid-summer reimplanting with TBA/E increased late-summer ADG, but ADG did not differ between PG/E and non-reimplanted steers in either Exp. Implications and Applications Reimplantation with TBA/E and DDG supplementation can intensify stocker cattle production on native range by increasing gain per hectare and net returns, but the long-term ecological im-pacts of these systems require study.
Objective: The study objective was to determine the effect of a probiotic containing Lactobacillus acidophilus and Lactobacillus casei fed daily to preweaning Holstein & times; Angus calves on growth, incidence of morbidity, liver score, gut morphology, rumen development, gut microbiome, and fecal pathogen shedding from 0 to 60 d. Materials and Methods: Preweaning Holstein & times; Angus cross calves age <48 h with serum total proteins >= 5.2 g/dL were randomly enrolled on 1 of 2 treatments:(1) Control (CON: n = 149), and (2) probiotic (PRO: n = 150). The PRO dose added to individual milk bottles and starter grain was to supply not less than 1 billion cfu/calf per day in milk and not less than 1 billion cfu/calf per day in starter grain. Results and Discussion: There were no differences in growth performance, meaures of scours, gut community structure, alpha-diversity or health indicators between treatments. But, there were tendencies for increased ileal crypt depth, increased blood glucose from 7 to 35 d and redued fecal shedding of Shiga toxin-producing Escherichia coli (E. coli STEC), corona virus at 42 d and Cryptosporidium at 21 d in PRO calves. Implications and Applications: Reducing fecal shedding of pathogens will reduce contamination of the environment and potentially reduce exposure of calves to pathogens.
Objective: Our objective was to evaluate the effect of kefir supplementation in calves through 21 d of life under different management conditions on growth, diarrhea incidence, and antibiotic use. Materials and Methods: Holstein heifers (n = 148) at 3 commercial farms were randomized to receive a control (CON; 60 mL of whole milk in farm A or nothing in farm B or C) or 60 mL of kefir (KEF) added to whole milk or milk replacer at the morning feeding until 21 d of life. Kefir was prepared as needed by trained personnel on each farm by fermenting salable whole milk with kefir grains for 24 h at 20 to 25 degrees C. Each farm used a similar experimental design and was analyzed independently from the others. Daily feed intake and refusals, as well as health scores, were recorded in farm A. Growth performance was measured weekly at farm A and at wk 4 and 8 at farms B and C. An aggregated data set for all 3 farms was created to compare growth performance at wk 4 and 8 of age. A subset of serum samples (n = 24) collected on d 21 at farm A was analyzed for free fatty acid composition. Results and Discussion: Calves receiving KEF in farm A had significantly greater starter DMI at wk 8 compared with CON, as well as greater circulating linoleic acid concentrations, though feed efficiency, preweaning BW, ADG, and occurrence of health events were not different. Improved BW before weaning, hip height, and hip width were observed with KEF supplementation in farm B compared with CON, but BW at weaning was not different among treatments across all 3 farms. However, calves receiving KEF at all 3 farms were 3 times more likely to double their birth weight by weaning than calves fed CON. Implications and Applications: Kefir supplementation in early life may improve starter intake before weaning, but more work is needed to further understand other potential metabolic or physiological influences.
Objective Our objective was to conduct a mixed model meta-regression investigating the effects of distillers grains (DG) supplementation on enteric methane emissions from lactating dairy cattle. Materials and Methods Nine experiments with 34 treatment means were collected for the analysis. Respira-tion chambers (2), head-box style respiration chambers (6), or Greenfeed (C-Lock; 1) were used to measure meth-ane in these experiments. We conducted a mixed model meta-regression with the fixed effect of DG and the ran-dom effect of study. All observations were weighted by the inverse of the squared SEM. We conducted subsequent analyses that included the effects of diet NDF, total FA, PUFA, and S. Results and Discussion In models with the fixed ef-fect of DG, methane production, yield, and intensity and methane as a proportion of GE intake (Ym) were all re-duced as DG inclusion increased. In models accounting for dietary nutrient composition, DG inclusion still reduced enteric methane production, yield, and intensity. Implications and Applications Inclusion of DG in diets for lactating dairy cattle reduces enteric methane production, yield, and intensity and Ym, which is likely caused by a variety of nutrients that DG delivers includ-ing FA and S.
Objective The objective was to complete a financial analysis of 2 dairy farm systems with cropping treatments designed to produce all of the forage needs using broadcast manure with standard herbicide (BMSH) versus injected manure with integrated weed management to reduce her-bicide (IMRH), using a virtual 65-cow herd with a 97-ha farm model. Materials and Methods The BMSH and IMRH treatments were implemented at 1/20th of the scale of the modeled cropland. Cropping data were collected from 2010 through 2017, and rations were balanced using NRC 7 (NRC, 2001) to simulate the 65-cow milking herd with dry cows and replacements. A model consisting of Mi-crosoft Excel and FINPACK (Center for Farm Financial Management, University of Minnesota, St. Paul, MN; FINPACK, 2022) was used to evaluate the economic per-formance of the milking herd with 97 ha of cropland. Excel was used for the actual cost for cropping and heifer rais-ing. All financial data came from FINPACK; current ra-tio, rate of return on assets, term debt coverage ratio, farm debt-to-asset ratio, operating expense ratio, total feed cost per cow, and cost of production per kilogram of milk were calculated for both treatments and compared via ANOVA with treatments and years as fixed effects. Results and Discussion The more environmentally sustainable treatment IMRH resulted in similar financial performance to the more traditional BMSH, with both cropping systems producing the majority of the forage and feed required for the herd, despite the cropping practice differences. Implications and Applications These results ad-dress the study objective by showing that the BMSH and IMRH systems produced comparable whole-farm financial performance when applied in a 65-cow, land-limited dairy system. Although differences in forage composition and manure and herbicide management influenced ration for-mulation and crop-related costs, these differences did not result in statistically significant changes to key financial indicators.
Objective: To evaluate timing of initial processing and respiratory vaccine delivery method on the health and performance of high-risk, newly received calves. Materials and Methods: Calves (n = 662) were blocked by arrival lot, stratified by castration status and BW, and allocated to pens assigned to 6 experimental treatment combinations in a 3 & times; 2 factorial arrangement. Treatment combinations included processing and intranasal (IN) respiratory vaccine at 0 d (0-dIN), processing and s.c. respiratory vaccine at 0 d (0-ds.c.), processing and IN at 2 d (2-dIN), processing and s.c. at 2 d (2-ds.c.), processing and IN at 14 d (14-dIN), and processing and s.c. at 14 d (14-ds.c.). Results and Discussion: As time until initial processing increased, so did days to first antimicrobial treatment for bovine respiratory disease (BRD). The 0-d processing group tended to have fewer second and had fewer third antimicrobials administered for BRD. The 0-d and 2-d groups had greater bovine viral diarrhea virus-specific titers than the 14-d group on d 14 and 28. There was a processing time by vaccine delivery method interaction for infectious bovine rhinotracheitis virus (IBRV)-specific antibody titers on d 56. A processing time main effect was observed on d 14 and 28 for IBRV-specific antibody titers where the 0-d groups had the highest. From d 15 through 28 and overall (d 0 through 56) the 0-d processing groups had the greatest ADG, the 2-d groups were intermediate, and the 14-d groups had the least. As a result, the 0-d groups had the greatest BW, the 2-d groups were intermediate, and the 14-d groups had the least on both d 28 and 56. The 0-d and 2-d groups had greater DMI than the 14-d group from d 15 through 56 and overall. There were differences in G:F from d 15 through 56 and overall, where the 0-d group had the greatest G:F overall. Calves receiving IN had greater DMI from d 1 through 28. Implications and Applications: Cattle processed immediately after feedlot arrival generally had improved health and performance outcomes compared with cattle that had initial processing procedures delayed, whereas vaccine delivery method had minimal impact.
Objective The objective of this study was to examine the effect of feeding colostrum once versus twice on growth and passive transfer immunity (PTI) of preweaning Holstein calves by measuring BW, withers height (WH), as well as serum total protein (STP) and Brix values. Materials and Methods On the day of birth (designated as d 1), 70 Holstein calves were weighed and as-signed randomly to one of the colostrum feeding groups: 1-feeding, n = 34; or 2-feeding, n = 36. Both groups received 4 L of pasteurized high-quality first-milking colostrum (Brix > 23%) between 2.5 and 3 h after birth. The 2-feeding group received an additional 2 L of first-milking colostrum 8 to 10 h after the first feeding. Thereafter, all calves were fed 3.5 L of pasteurized whole milk twice daily and provided ad libitum access to calf starter. Blood samples, WH, and BW were obtained on d 3 and 7. Also, WH and BW were measured on d 30 and 45. Health status was scored and recorded during the experiment. Serum Brix and STP were measured using digital and optical refractometers, respectively. The differences in Brix, STP, IgG, WH, and BW were analyzed by ANOVA, repeated measures. Results and Discussion Body weight, WH, and ADG (d 1 to 45) were not different in calves fed 2 doses of pasteurized colostrum or fed 1 dose of colostrum. Furthermore, during the first 45 d after birth, no mortality or morbidity were observed in the 2 groups. Mean STP and Brix were affected by treatment and feeding frequency by day interaction. On d 3, mean STP and Brix were greater in 2-feeding than 1-feeding (STP: 7.4 vs. 7.1 +/- 0.1 g/dL; Brix: 10.9% vs. 10.3% +/- 0.1%), respectively. Mean STP and Brix decreased in both groups by d 7, but tended to be greater in 2-feeding than 1-feeding (STP: 7.3 vs. 6.5 +/- 0.2 g/dL; Brix: 10.7% vs. 9.8% +/- 0.2%). Implications and Applications Well-established evidence supports the importance of colostrum quality, cleanliness, and timing for calf immunity, but the effects of feeding frequency on PTI and calf performance are in-consistent. Despite marginal differences in serum Brix and STP between the 1- and 2-feeding groups, both measures were above the recommended critical thresholds, suggesting that successful passive transfer of immunity was achieved with either 1 or 2 timely feedings of pasteurized high-quality colostrum. The colostrum frequency treatment did not influence the growth performance and health of preweaning calves.
Objective: Our objective was to compare prebreeding nutritional management systems of either a dry lot (DLOT) ration or grazing of winter triticale (TRIT) on reproductive performance of yearling Bos taurus heifers. Materials and Methods: In each of 4 yr, heifers (n = 168, 86, 97, and 103, respectively) were allotted to treatment 39 f 8.3 d before artificial insemination (AI). Dry lot heifers received a growing ration (10.6% to 14.5% CP) composed of ranch-produced forages supplemented with corn and distillers grain. Winter triticale ranged in CP from 28.6% at the start of the study to 16.9% at AI. Estrus was synchronized with a 14-d controlled internal drug-release device (CIDR) plus prostaglandin F2 alpha (PG) fixed-time AI protocol, with AI 66 h after PG. Estrus-detection patches were used to determine estrous response after CIDR removal and before AI. Serum samples were collected at PG administration and at AI for determination of serum urea nitrogen and nonesterified fatty acid analysis. Results and Discussion: Starting BW and BCS were not significantly different between management systems. Also, estrous response after CIDR removal or at AI did not differ significantly because of management. Body condition change tended to be greater for TRIT (0.45 f 0.14) than DLOT (-0.02 f 0.14). Pregnancy rate to AI was greater in DLOT (59.1 f 3.2%) than in TRIT (42.1 f 3.2%). Serum urea nitrogen concentrations were greater in TRIT than in DLOT at PG administration and at AI. Implications and Applications: Grazing triticale before breeding can improve heifer body condition. However, heifers that graze triticale may have reduced pregnancy rates compared with those fed in a dry lot at least 30 d before breeding.
Objective: Evaluate the effects of the maternal bovine appeasing substance (mBAS) on feedlot performance, health outcomes, hair cortisol concentrations, and carcass characteristics for northern US-origin yearling beef steers. Materials and Methods: Crossbred steers (n = 1,754; initial BW = 424 kg, SD = 25 kg) were received on 7 arrival dates to a commercial Nebraska feedyard, gate sorted into 20 pens, and pens were randomly assigned to receive (1) 10 mL of mBAS (FerAppease, FERA Diagnostics and Biologicals) or (2) 10 mL of mineral oil placebo (CON). Treatments were applied topically to the poll and muzzle (5 mL at each site) at initial processing and reimplant. A subset of 5 steers per pen (n = 100) were randomly selected for hair sampling at arrival and d 14 to assess cortisol. Steers were fed a high-moisture, corn-based finishing diet for 167 d on feed before harvest. Results and Discussion: Dry matter intake and ADG did not differ between treatments. Carcass-adjusted G:F tended to improve for mBAS on a deads-in basis. Hot carcass weight, LM area, and marbling score were similar, though dressing percent tended to be greater with mBAS. Quality grade and yield grade distributions did not differ between treatments. Administering mBAS did not affect treatment frequency for illness, overall mortality rate, or hair cortisol concentrations. Implications and Applications: Topical mBAS application at arrival and reimplant did not influence growth, health, or cortisol, but may modestly improve carcass-adfeed in steers.
Objective: We determined the effects of ferric citrate supplementation on energy partitioning, methane production, and nutrient balance in growing beef steers. Materials and Methods: Angus steers (n = 8; initial BW = 363 +/- 30.4 kg) were used in a replicated 4 & times; 4 Latin square design experiment. Treatments were as follows: (1) 0 mg of ferric citrate (F0, control); (2) 250 mg Fe/kg DM as ferric citrate (F250); (3) 500 mg Fe/kg DM as ferric citrate (F500); or (4) 750 mg Fe/kg DM as ferric citrate (F750). After a 16-d diet adaptation period, dietary treatment, orts, feces, and urine were collected and composited over a 5-d collection period. On d 3 of each collection period, gas exchange was measured using indirect calorimetry headboxes. Results and Discussion: Methane energy loss tended to decrease quadratically, with F0 and F750 steers having greater methane energy losses than F250 and F500 steers. Subsequently, ME decreased linearly, and ME as a proportion of GE intake tended to decrease, with increasing concentrations of ferric citrate. Retained energy and retained energy as a proportion of GE intake tended to decrease linearly as ferric citrate concentration increased. In addition, fecal nitrogen excretion tended to increase as ferric citrate concentration increased. Implications and Applications: Collectively, these findings suggest that ferric citrate could slightly decrease CH4 energy losses at concentrations below 500 mg. Nonetheless, linear decreases in ME and retained energy suggest that ferric citrate inclusion may have detrimental effects on energy balance that limit its application in growing beef steers. Therefore, potential environmental benefits are negated by the decrease in energetic efficiency. Overall, these findings do not support the use of ferric citrate for CH4 mitigation.
Purpose: Our purpose was to synthesize literature relevant to vitamin A use in beef cow-calf systems, with emphasis on how current beef cow vitamin A requirements were derived, and the limitations of the underlying evidence, and key knowledge gaps that constrain confident supplementation decisions. Sources: Information was sourced from peer-reviewed papers and our own unpublished data. Synthesis: Vitamin A is a crucial micronutrient, affecting health, reproduction, and growth. Neonatal beef calves are the most vulnerable to vitamin A deficiency in cow-calf systems, are born with limited retinol stores, and are dependent on colostral retinol. There is limited understanding of how cow retinol liver stores and dietary vitamin A consumption influence calf status. Calves deficient in vitamin A are more likely to suffer respiratory disease or diarrhea, leading to reduced productivity. Current supplemental recommendations for vitamin A as provided by NASEM (2016) are limited by the small number of studies, which date to the mid 1900s. These recommendations do not account for variation in the basal diet 3-carotene concentration, which can vary drastically. Conclusions and Applications: Colostral retinol is crucial to prevent vitamin A deficiency in newborn calves; however, limited research has explored the vitamin A needs of the gestating cow to support a healthy, productive calf. Many factors need to be considered when evaluating the vitamin A requirements of beef cows, including stage of gestation, liver vitamin A stores, and harvest and storage conditions of forages. Further research is needed to identify supplemental vitamin A concentrations that best support the gestating cow providing for the calf, to identify proper supplemental vitamin A needs when cows are consuming varying basal diets, and to understand the interactions between vitamin A and other vital nutrients.
Objective: Our objective was to determine the effects of feeding commercial Angus yearling steers once (1 & times;) or twice (2 & times;) per day on feedlot performance and carcass characteristics. Materials and Methods: Steers (n = 64; BW = 328 +/- 22 kg) were blocked by BW and randomly assigned to feedlot pens measuring 4.57 & times; 15.24 m (n = 4 steers per pen). Pens were randomly assigned to 1 of 2 experimental treatments: 1 & times; or 2 & times;. Steers were fed a finishing diet consisting of primarily dry-rolled corn for 141 d. The only difference between experimental treatments was the frequency of feed delivery. Steers on the 1 & times; treatment received 100% of the daily feed call at 0930 h, whereas steers on the 2 & times; treatment received 50% of the daily feed call at 0930 and 1400 h. Feed was delivered to steers in fence-line (4.57 m in length) concrete bunks (1.14 m per steer). Pen served as the experimental unit, and all steers were slaughtered on d 142. Results and Discussion: There were no differences in final BW or overall ADG between the experimental treatments; however, overall DMI was greater for steers fed 1 & times;. Conversely, steers fed 2 & times; were 4.0% more feed efficient over the entire feeding period. There were no differences between the 2 experimental treatments for any of the carcass characteristics measured. Implications and Applications: Intake was greater for steers fed 1 & times;, and efficiency was greater for steers fed 2 & times;. Although operation-specific logistics must be considered, feeding cattle 2 & times; as opposed to 1 & times; could optimize performance in conditions similar to those in the current experiment.
Objective: The objective of this experiment was to examine the long-term effects of distillers grain supplementation and nitrogen (N) fertilization on animal performance to determine whether cattle supplemented with dry distillers grains plus solubles (DDGS) can be stocked at the same rate as nonsupplemented cattle on N-fertilized smooth bromegrass pastures. Materials and Methods: Each year, 45 steer calves weighing 321 +/- 27 kg were assigned to 1 of 3 treatments. Treatments consisted of (1) steers grazing nonfertilized smooth bromegrass pastures supplemented with DDGS at 0.6% of BW (DM basis; SUPP); (2) steers grazing smooth bromegrass pastures fertilized with 90 kg of N/ha (FERT); or (3) steers grazing unfertilized smooth bromegrass pastures without DDGS supplementation (CONT). Pasture was the experimental unit, with 3 replications per treatment each year, and pastures were rotationally grazed during the grazing season. The CONT treatment pastures were 30% larger than the SUPP and FERT pastures, based on previous research indicating that nonfertilized pastures produced similar to 70% as much forage as fertilized pastures. Results and Discussion: Across the 17 yr, cattle on the SUPP treatment had greater ADG (1.03 kg) than those on CONT (0.73 kg) and FERT treatments (0.73 kg), which were similar to one another. Similar ADG between the CONT and FERT demonstrate that forage availability was the same and appropriate pasture sizes were used. Body weight gain per hectare was greatest for the SUPP treatment (378 kg/ha), intermediate for the FERT treatment (271 kg/ha), and least for the CONT treatment (186 kg/ha). Implications and Applications: Pasture use efficiency is increased through DDGS supplementation or fertilization of pastures, with the SUPP treatment being the most productive per hectare. Responses vary across years due to precipitation and pasture performance.
Objective: We aimed to evaluate the effects of ionophore type and type of diet on growth performance in Holstein calves during the preweaning and grower phases. Materials and Methods: In experiment (Exp.) 1, 118 Holstein calves (2 +/- 1 d old) were assigned randomly to a pelleted calf starter with either monensin (MON) or lasalocid (LAS) at 55 mg/kg (as-fed basis). Along with calf starter, milk replacer (28% CP and 20% fat) was fed through 56 d, followed by feeding calf starter alone through d 91 to measure calf ADG and DMI. In Exp. 2, 75 calves used in Exp. 1 were randomly assigned within previous treatments to 3 diets (5 pens/treatment; 5 calves/ pen) to evaluate ADG and DMI after weaning. Dietary treatments (fed for 70 d) included a high-concentrate diet with MON (HC-MON), a high-concentrate diet with LAS (HC-LAS), and a high-forage diet with MON (HF-MON). Results and Discussion: In Exp. 1, type of ionophore did not influence starter intake or performance during the preweaning period; however, LAS calves had increased starter intake and ADG the 2 wk immediately after weaning. In Exp. 2, calves fed HC-LAS or HC-MON had greater ADG and tended to have a greater G:F than those fed HF-MON. Implications and Applications: Data suggest that lasalocid supplementation improved calf ADG during the immediate postweaning period. During the grower phase, calves fed a high-concentrate diet had increased performance compared with those fed a higher-forage diet.
