Applied Animal Science最新文献

{"title":"Perspective and Commentary: Summary of the Special Issue on calf and stocker performance effects on feedlot performance and thoughts on future research","authors":"Daniel Rivera ,&nbsp;Paul Beck","doi":"10.15232/aas.2025-02716","DOIUrl":"10.15232/aas.2025-02716","url":null,"abstract":"<div><h3>Purpose</h3><div>The objective of this article was to summarize information in 7 original research articles and 2 reviews submitted, reviewed, and accepted for this Special Issue on possible preweaning calf and stocker calf performance factors influencing subsequent feedlot performance. Additionally, thoughts regarding future directions for research are presented.</div></div><div><h3>Sources</h3><div>A call for papers was released in early 2024 for topics that evaluated the effects of postweaning management on subsequent feedlot performance in beef cattle. Seven original research articles and 2 reviews were submitted.</div></div><div><h3>Synthesis</h3><div>This Special Issue represents research findings and reviews of information to expand our understanding of factors in the preweaning and stocker phases that might influence subsequent feedlot performance. Information is presented in the Health, Nutrition, and Production and Management sections. The segmented nature of the beef industry leads to segmented areas of research focused on the individual cow-calf, stocker, and feedlot segments. Thus, there is a dearth of consistent information examining long-term effects of pre- and postweaning treatments and factors across the various segments, including feedlot performance and carcass characteristics.</div></div><div><h3>Conclusions and Applications</h3><div>Our goal for this Special Issue was to identify and address some of the knowledge gaps. As noted in the 2 reviews, data regarding long-term effects needs to be collected in a more standardized and consistent way among various research locations. Although the research findings submitted to this Special Issue add to our body of knowledge, there are still many other avenues to explore. However, given the complexity of a system-type approach to fully explore these questions, it is imperative that researchers and Extension personnel collaborate (across state and regional lines) to find ways to address these needs.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 4","pages":"Pages 399-404"},"PeriodicalIF":1.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Invited Review: Effects of management on performance of stocker cattle and subsequent feedlot performance: A review within Applied Animal Science","authors":"M.A. Snider ,&nbsp;M.S. Gadberry ,&nbsp;J.D. Rivera","doi":"10.15232/aas.2024-02663","DOIUrl":"10.15232/aas.2024-02663","url":null,"abstract":"<div><h3>Purpose</h3><div>The purpose of this review is to summarize relevant research from the journal <em>Applied Animal Science</em> (formerly known as <em>The Professional Animal Scientist</em>) between 1995 and 2024, that explores management practices and concepts as they relate to stocker calf performance and subsequent feedlot performance. A secondary objective of this review is to describe research trends and identify knowledge and research gaps within existing literature.</div></div><div><h3>Sources</h3><div>Sources for this article included peer-reviewed scientific literature obtained from the journal <em>Applied Animal Science</em>, formerly known as <em>The Professional Animal Scientist</em>. Literature used in this review included original research, short communications, technical notes, meta- analyses, and review articles between 1995 and 2024. A primary search excluded literature that were on species other than beef and dairy cattle. From there, a secondary search evaluated literature for inclusion if it contained the following key words: stocker, growing, grazing, yearling, grazing, backgrounding, cow-calf, feedlot(s), and finishing/finisher. Literature was excluded from this review if the study solely evaluated cow-calf or feedlot enterprises. Additionally, literature was excluded if there was not a stocker or grazing component to the study. Sources were further divided by the state or region in which the research was conducted to identify general production system locations and practices.</div></div><div><h3>Synthesis</h3><div>Stocker and feedlot phases of beef production systems are 2 crucial phases in the beef supply chain, with each phase serving distinct roles in the beef life cycle. Most weaned calves will go directly into stocker/backgrounding programs, thereby making stocker calf management critical. Stocker production management practices may vary based on numerous factors, such as climate, resource availability, and producer goals, potentially affecting subsequent feedlot performance.</div></div><div><h3>Conclusions and Applications</h3><div>Future research should focus on an all-encompassing systems approach, following calves from birth through the retail and marketing processes, and examine effects of health and technology integration.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 4","pages":"Pages 329-349"},"PeriodicalIF":1.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of postweaning management of beef × dairy hybrid steers on performance, efficiency, and carcass characteristics","authors":"Ally Grote ,&nbsp;Olivia Genther-Schroeder ,&nbsp;Blake K. Wilson ,&nbsp;Troy Wistuba ,&nbsp;Paul Beck","doi":"10.15232/aas.2024-02585","DOIUrl":"10.15232/aas.2024-02585","url":null,"abstract":"<div><h3>Objective</h3><div>Our objective was to determine the per- formance, efficiency, and carcass quality in beef × dairy crossbred steers that were either placed directly on feed following weaning (FIN) or following an average stocker grazing period of 217 d (GRW/FIN).</div></div><div><h3>Materials and Methods</h3><div>Beef × dairy hybrid steers (n = 475) from Land O’Lakes Calf Milk Research Facility (Gray Summit, MO) at 12 wk of age were transported to the Willard Sparks Beef Research Center (WSBRC; Still- water, OK) in groups (n = 8) of 57 to 72 steers. Steers in the first group to arrive were allocated to either GRW/FIN or FIN treatment by BW, previous treatment, and breed of sire for each finishing treatment. Subsequent groups were all assigned either to FIN or GRW/FIN finishing treatments. Paired groups of FIN and GRW/FIN with overlapping feeding dates were considered a random block (n = 4) for statistical analysis. At WSBRC, steers were sorted by BW within sire breed and preweaning treatment into pens of 4 to 5 steers each and finished to a targeted 1.3 cm backfat. Data were analyzed using the Mixed pro- cedure of SAS 9.4 (SAS Institute Inc., Cary, NC), with pen within block as the experimental unit.</div></div><div><h3>Results and Discussion</h3><div>Steers in GRW/FIN had greater (<em>P</em> &lt; 0.01) BW and hot carcass weight while re- quiring fewer (<em>P</em> &lt; 0.01) days on feed compared with FIN steers but were 75 d older at harvest. Average daily gain and feed intake were greater but G:F was lesser (<em>P</em> &lt; 0.01) for GRW/FIN. Steers in GRW/FIN had a greater (<em>P</em> ≤ 0.03) ribeye area, marbling score, and percentage of USDA High Choice and Prime carcasses and fewer USDA Select carcasses (<em>P</em> &lt; 0.05) compared with FIN steers.</div></div><div><h3>Implications and Applications</h3><div>Grazing beef × dairy crossbred steers before finishing increased animal performance and improved carcass characteristics but also increased daily feed intake compared with calves placed directly on feed. Beef × dairy crossbred calves offer a viable alternative to straight-bred dairy calves, but it is necessary to determine proper management strategies for these calves.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 4","pages":"Pages 350-362"},"PeriodicalIF":1.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of beef calf health status during receiving on subsequent performance during stocker and finishing phases of production*","authors":"Paul Beck ,&nbsp;Matt R. Beck ,&nbsp;Daniel Rivera ,&nbsp;Beth Kegley ,&nbsp;Gerald Horn","doi":"10.15232/aas.2024-02576","DOIUrl":"10.15232/aas.2024-02576","url":null,"abstract":"<div><h3>Objective</h3><div>The objective of this analysis was to de- termine the effects of purchasing cattle as steers or bulls and bovine respiratory disease (BRD) treatment of stocker calves during receiving on performance during subsequent stages of production.</div></div><div><h3>Materials and Methods</h3><div>This post hoc analysis used mixed steer and bull calves with full health data records (n = 1,965) from 9 experiments, steer calves with receiv- ing health data and subsequent grazing performance data (n = 2,032) from 10 experiments, and steer calves with receiving health data with subsequent grazing and fin- ishing performance data (n = 423) from 2 experiments. Data were analyzed as random effects or generalized linear mixed models with experiment as the random effect in the R software.</div></div><div><h3>Results and Discussion</h3><div>Calves received as intact bulls (n = 1,064) were 2.41-, 2.25-, 2.68-, or 2.94-times more likely to have a first, second, third, and fourth treat- ment, respectively, than calves that were received as steers (n = 901). Bulls were also 1.16-times more likely to have chronic morbidity and 2.27-times more likely to have BRD mortality than steers. As the number of BRD treatments increased, ADG during receiving decreased. This carried over for reduced BW during turnout on pasture and at the end of grazing. When steers were followed through finishing, increased number of BRD treatments during the stocker receiving period reduced BW at slaughter, hot car- cass weight, and marbling and increased the number of days on feed to achieve a calculated 28% empty body fat carcass (based on equations by Guiroy et al., 2001).</div></div><div><h3>Implications and Applications</h3><div>Bovine respiratory disease has long-term implications on performance, not only during the receiving period but also on BW and productivity following the stocker grazing phase and fin- ishing. We observed no compensatory gain on pasture or during finishing from reduced performance due to health issues in the receiving phase. Increased BRD morbidity and less favorable health outcomes for calves arriving as intact bulls would require at least a $0.50/kg discount for intact bulls for equivalent net returns to steers.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 4","pages":"Pages 284-297"},"PeriodicalIF":1.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plane of nutrition through 92 days of age in beef × dairy hybrid steers influences subsequent finishing performance, feed efficiency, and carcass characteristics","authors":"Ally Grote ,&nbsp;Olivia Genther-Schroeder ,&nbsp;Blake K. Wilson ,&nbsp;Troy Wistuba ,&nbsp;Paul Beck","doi":"10.15232/aas.2024-02607","DOIUrl":"10.15232/aas.2024-02607","url":null,"abstract":"<div><h3>Objective</h3><div>Our objective was to determine the effect of plane of nutrition through 92 d of age on subsequent finishing performance, feed efficiency, and carcass characteristics in beef × dairy crossbred steers.</div></div><div><h3>Materials and Methods</h3><div>Beef × dairy crossbred steers (n = 109) were acquired from commercial dairies in blocks (n = 2) with 38 and 72 steers per block and transported to the Calf Milk Research Facility at Purina Animal Nutrition in Grey Summit, Missouri, at 7 d of age. Steers were assigned to either a higher nutrient-dense milk replacer (MR) and starter (HI) or moderate nutrient- dense MR and starter (MOD) plane of nutrition through 92 d of age. Steers were weaned at 49 d and sorted into outdoor pens with 3 steers per pen. On d 84, steers were transported to the Willard Sparks Beef Research Center (WSBRC) in Stillwater, Oklahoma. At the WSBRC, steers were sorted by BW within preweaning treatment into 4 to 5 steers/pen and fed for 308 d. Data were analyzed using SAS 9.4 Mixed procedure (SAS Institute Inc., Cary, NC) for all performance and noncategorical carcass measures. For preweaning measurements, individual calf was used as the experimental unit, whereas for finishing phase measurements pen was the experimental unit.</div></div><div><h3>Results and Discussion</h3><div>Steers fed HI prefinishing exhibited a greater BW through d 168 of the finishing phase and had greater DMI from d 0 to 28 and d 28 to 112, as well as greater percentage USDA Choice. Steers fed MOD had a greater G:F from d 28 to 112 and had greater overall G:F. There were no other differences in carcass characteristics due to preweaning plane of nutrition.</div></div><div><h3>Implications and Applications</h3><div>Providing calves with lesser nutrient-dense diets during the preweaning period, such as MOD treatment of the current research, did not result in enhanced performance through compensatory gain. Based on this study, a higher preweaning plane of nutrition allows heavier BW through 29 wk of age and improved carcass quality.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 4","pages":"Pages 307-318"},"PeriodicalIF":1.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of flexible prepartum supplementation strategies on cow-calf and subsequent progeny feedlot performance in a May-calving herd","authors":"Jacki A. Musgrave ,&nbsp;Kacie L. McCarthy ,&nbsp;J. Travis Mulliniks","doi":"10.15232/aas.2024-02597","DOIUrl":"10.15232/aas.2024-02597","url":null,"abstract":"<div><h3>Objective</h3><div>The objective of this study was to evalu- ate the effects of minimal and flexible supplementation strategies on reproduction, cow BW, and subsequent calf performance in May-calving mature cows grazing upland native range.</div></div><div><h3>Materials and Methods</h3><div>Cows received one of 3 sup- plementation strategies: (1) 0.227 kg per day of a 30% CP distillers-based supplement (HalfSupp), (2) 0.454 kg per day of a 30% CP distillers-based supplement (Supp), or (3) brief and intermittent supplementation of Supp at 0.454 kg/cow based on periods of acute environmental stress, such as snow cover and wet winter events, which is best described as flexible supplementation (Flex). Supple- mentation was initiated in January each year and termi- nated approximately 30 d before the start of the calving season in April. After weaning, steers grazed subirrigated meadow with a dried distillers grain supplement until May. In May, all steers grazed subirrigated meadow with- out additional supplement until August/September when steers were shipped to the feedlot. Steers were placed in a GrowSafe feeding system for the rest of the finishing feeding period.</div></div><div><h3>Results and Discussion</h3><div>Cow BW was not different at the initiation of supplementation in January. However, cows fed HalfSupp had a lighter BW at precalving and tended to have a lighter BW at prebreeding than their counterparts. After a 45-d breeding season, pregnancy rates were not influenced by prepartum supplementation strategies. Prepartum supplementation strategies did not influence preweaning calf BW at birth, prebreeding, and weaning. In addition, steer backgrounding BW was also not influenced by their dam’s prepartum supplementation strategy. Upon entry into the feedlot, steer feedlot perfor- mance (BW, ADG, and feed efficiency) was not influenced by their dam’s prepartum supplementation strategy. After slaughter, no carcass characteristics were affected by the dam’s prepartum supplementation strategy.</div></div><div><h3>Implications and Applications</h3><div>Considering the cost of prepartum supplementation, feeding a protein supple- ment just during environmentally stressful periods during gestation appears to be a viable alternative to more conventional methods and reduces winter feed costs.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 4","pages":"Pages 298-306"},"PeriodicalIF":1.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extended effects of postweaning management in southeastern beef calves","authors":"S. Maggie Justice ,&nbsp;M. Kimberly Mullenix ,&nbsp;Manuel F. Chamorro ,&nbsp;D. Alex Tigue ,&nbsp;S.L. Dillard ,&nbsp;W.B. Smith ,&nbsp;S.P. Rodning","doi":"10.15232/aas.2024-02589","DOIUrl":"10.15232/aas.2024-02589","url":null,"abstract":"<div><h3>Objective</h3><div>Understanding the effects of postweaning management strategy on calf performance and health can help producers add value to their operations and further strengthen the viability of the beef supply chain. Our objective with this study was to evaluate the effects of weaning and postweaning management practices and potential carryover effects on calf immune system viability and performance through the feedyard finishing phase.</div></div><div><h3>Materials and Methods</h3><div>A 2-yr study was conducted using 429 steer calves from 3 Auburn University research farms. Calves were randomly assigned based on weaning weights to 1 of 3 different weaning method groups: fence-line weaning, nose-flap weaning, or abrupt weaning. After the weaning period (14 d), calves were brought to a centralized farm and began a 60-d backgrounding period where they were randomized according to previous weaning management, farm of origin, and BW to 1 of 3 nutritional management strategies in a 3 × 3 split-plot design: cool-season baleage and 1% BW dried distillers grain (DDGS), bermudagrass hay and 1% BW DDGS, or grazing of mixed warm-season annuals and 1% BW DDGS. Body weights were collected throughout the trial to measure growth and performance. Blood samples were collected throughout the backgrounding period to measure vaccination response. Following backgrounding calves were transported to a commercial feedyard and followed until finishing.</div></div><div><h3>Results and Discussion</h3><div>Fence-line-weaned calves had the greatest ADG (<em>P</em> = 0.02) in the first 30 d of the backgrounding period regardless of backgrounding diet type. Calves fed the bermudagrass-hay-based diet also had a greater ADG (<em>P</em> &lt; 0.0001) than both the grazing and baleage diet groups in the first 30 d of backgrounding. Steers on both the warm-season annual grazing and cool- season baleage diets supported greater ADG (<em>P</em> = 0.0041) during the last 30 d of the backgrounding period.</div></div><div><h3>Implications and Applications</h3><div>Results indicate that weaning and backgrounding management strategies may influence calf performance during the transition period into the postweaning phase and performance in the feedyard phase.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 4","pages":"Pages 363-376"},"PeriodicalIF":1.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review: Vaccination against respiratory pathogens during the cow-calf phase: Effects on productive and health responses of feedlot cattle","authors":"Kelsey M. Harvey ,&nbsp;Reinaldo F. Cooke ,&nbsp;W. Isaac Jumper","doi":"10.15232/aas.2024-02592","DOIUrl":"10.15232/aas.2024-02592","url":null,"abstract":"<div><h3>Purpose</h3><div>Bovine respiratory disease (BRD) remains one of the costliest diseases affecting the beef industry, and vaccination is a key strategy to mitigate disease risk. This article discusses current knowledge of vaccine use and strategies during the cow-calf phase of beef production.</div></div><div><h3>Sources</h3><div>The primary source of information reviewed herein was independent, published, scientific peer-re- viewed literature.</div></div><div><h3>Synthesis</h3><div>Producers prioritize vaccination protocols as cattle progress through the segments of the beef pro- duction system, with BRD vaccine adoption rate increas- ing as cattle age. Vaccination against BRD pathogens dur- ing the cow-calf phase and before stressful events such as weaning, transportation, or feedlot entry enhances vaccine efficacy and health responses in feedlot cattle.</div></div><div><h3>Conclusions and Applications</h3><div>To maximize vac- cine effectiveness and ensure optimal protection from disease, the timing of vaccinations against BRD pathogens relative to disease challenge must be considered. Research is warranted to further explore the benefits of vaccination against BRD pathogens during the cow-calf phase on cattle health and performance during the feed- lot period.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 4","pages":"Pages 273-283"},"PeriodicalIF":1.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of stocking rate on perinatal cows and subsequent growth and performance of calves from birth to carcass: A long-term epigenetic analysis","authors":"Douglas R. Tolleson ,&nbsp;Dan Quadros ,&nbsp;Charles R. Long ,&nbsp;Kelli D. Norman ,&nbsp;Monte Rouquette Jr.","doi":"10.15232/aas.2024-02605","DOIUrl":"10.15232/aas.2024-02605","url":null,"abstract":"<div><h3>Objective</h3><div>Our objective was to analyze long-term cow-calf records to document effects of perinatal stocking rates on subsequent cow and calf performance from birth to slaughter.</div></div><div><h3>Materials and Methods</h3><div>Over 1,900 cattle records from F-1 (Hereford or Angus × Brahman) cows calving in the fall or winter and stocked on bermudagrass at 3 distinct stocking rates (i.e., low [LO; 2.4 cow-calf pairs {CC} per hectare], moderate [MOD; 3.8 CC per hectare], or high [HI; 5.8 CC per hectare]) were analyzed. At termination of the stocker period, calves were shipped to a commercial feedlot. When most of the cattle in a pen reached a visual backfat of 1.25 cm, they were weighed and shipped 50 km to an abattoir for slaughtering and carcass grading. Carcass traits included hot carcass weight, DP, backfat, marbling score, predicted YG, longissimus muscle area, and KPH percentage.</div></div><div><h3>Results and Discussion</h3><div>Calving season, cow age, calf sex, gestation stocking rate (for a given CC and for the cow’s previous calf), and lactation stocking rate had various effects on cow, suckling calf, feedlot yearling, and carcass measures. High stocking rate generally decreased calf performance, yearling feedlot performance, and carcass parameters.</div></div><div><h3>Implications and Applications</h3><div>Stocking rate during gestation had substantial implications for cow, fetus, and calf nutrition and, thus, subsequent offspring performance from birth to slaughter. Stocking rate, particularly during the calf rearing period, was a critical component of grazing management within the context of weather, site production potential, and operational strategy.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 4","pages":"Pages 377-398"},"PeriodicalIF":1.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vitro and in situ estimation of ruminal and intestinal digestion of lobster and crab shell meal","authors":"T.C. Stahl ,&nbsp;L.J. Valentine ,&nbsp;A. Abend ,&nbsp;T. Islam ,&nbsp;P.S. Erickson","doi":"10.15232/aas.2024-02632","DOIUrl":"10.15232/aas.2024-02632","url":null,"abstract":"<div><h3>Objective</h3><div>This experiment compared in vitro dry matter digestibility (IVDMD), in vitro intestinal protein degradability, and in situ degradability of lobster shell meal (LM), crab shell meal (CM), soybean meal (SBM), and blood meal (BM), and chitin degradability of LM and CM.</div></div><div><h3>Materials and methods</h3><div>The 48-h IVDMD was determined in rumen fluid. For in situ DM and CP degradability, 4 Holstein cows were used to test the degradation rates of SBM, BM, LM, and CM. Samples were removed after 2, 4, 8, 12, 24, and 48 h. Protein fractions and degradation rates were determined. Fraction A was the washout before rumen suspension. Fraction C was the material remaining after 48 h. Fraction B was the initial sample − (A + C). The CP degradation rate was calculated by converting fraction B to the natural log and calculating the slope. The effective CP degradability was calculated by multiplying the sum of fractions A and B by the CP degradation rate and dividing that by the sum of the CP degradation rate and the outflow rate (2%, 5%, or 8%). For intestinal digestibility, Dacron bags (Ankom R510, pore size 50 μm, Ankom Technology) were removed from the rumen at 12 h, incubated with HCl and pepsin for 1 h, and then incubated for 12 h with protease and buffer to mimic intestinal digestion. After removal, sample bags were dried for 48 h at 55°C.</div></div><div><h3>Results and Discussion</h3><div>Soybean meal was more soluble than other feeds, and BM tended to be less soluble than LM or CM. Similarly, 12-h DM degradability was greater for SBM than for BM, LM, and CM; and BM was less than LM and CM. Intestinal DM digestibility was similar among feeds. Blood meal intestinal digestibility was estimated to be more than that of LM or CM. Rumendegradable protein was greater for SBM than for the other feeds. Blood meal was more degradable than LM and CM. Protein fraction A was similar for LM and CM, whereas fraction B and fractions A + B tended to be greater for CM than LM and fraction C tended to be greater for LM than CM. Soybean meal had greater fraction B and the sum of fractions A and B than the other feeds, and lesser fraction C. Degradation rates were greater for SBM than they were for the other feeds. Soluble chitin was greater for CM than LM, but degradability rates at 12 h and 48 h were similar.</div></div><div><h3>Implications and applications</h3><div>Results indicate that crustacean shell wastes may be used in cattle diets. More research should be conducted on feeding them to cattle.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 3","pages":"Pages 148-155"},"PeriodicalIF":1.4,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144263197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}