Cow-calf Operations Research Articles

Effects of cow feed efficiency, longevity, heterosis, and lifetime productivity on profitability of heifer selection and cow-calf operations

This study investigated factors influencing heifer replacement and cow-calf profitability using 361 cows (born 2011-2018) at the Lacombe Research and Development Centre, Alberta, Canada. Profitability was measured by marginal returns (MR) incorporating feed costs, heifer opportunity cost, calf and cull revenues, and a premium for cows retained in the herd. The study evaluated the linear effects of lifetime productivity, feed efficiency (residual feed intake adjusted for off-test backfat thickness; RFIfat), and genomic retained heterozygosity, an indicator of heterosis, on MR, feed costs, total costs, and net revenue (NR). Lifetime productivity, defined by the cumulative weight of calves weaned, was positively associated with MR and NR (P < 0.01). RFIfat influenced total cost, MR, and NR (P < 0.05), with MR improved by $168.50 cow-1 yr-1 for each unit decrease in RFIfat, although regression and group mean comparisons were not fully consistent. Genomic retained heterozygosity positively impacted MR and NR, with a 10% increase enhanced MR and NR by $21.80 and $20.50 cow-1 yr-1, respectively. Cow breed type did not affect longevity, MR, or NR. In conclusion, RFIfat and genomic diversity were important factors to consider in heifer replacement decisions when lifetime DMI was estimated as described in the present study.

PSV-21 Effects of supplementation programs for cow-calf operations during the dry grazing period under tropical conditions

Abstract The potential for increasing the productivity in cow-calf operation has gained wide acceptance in the last decade among Brazilian farms. Our objectives were to assess the impacts of providing supplementation to pregnant beef cows during the dry grazing period on cow and calf performance. During a 2-yr period, Tabapuã cows (n = 36) were blocked by parity and body weight (BW), and randomly assigned to pastures at the beginning of the rainy season. Brachiaria pastures were assigned to receive i) no application of N and cows were supplemented with mineral mix (CON), ii) application of 165 kg of Nּ ha-1ּ yr-1 and cows supplemented with a commercial product containing 40% of CP, macro and micro minerals, and vitamins (SUP), or iii) application of 165 kg of Nּ ha-1ּ yr-1 and cows supplemented with grass silage (GS). For SUP system, one-half of the paddocks were deferred in late summer. For GS system, one-half of the paddocks were deferred in early summer and silage was made after 90 d of regrowth. During silage making, 21% of DDGs on a dry matter (DM) basis was mixed into grass. After silage harvesting, the area was differed again. At the beginning of the dry period, deferred areas had free access to animals for SUP and GS treatments. The commercial supplement and silage were fed for 140 d (from 116 ± 27 to 256 ± 27 d of gestation). The mineral mix was offered all year round. The PROC MIXED procedure of SAS was used to analyze all variables. The statistical model included supplementation program as a fixed effect. Block, paddock, and year were included as random variables. Initial BW, initial body condition score (BCS), and gestation period of cows were included as covariates. Initial BW and BCS, and final BW and BCS did not differ among treatments. The GS treatment provided the greatest average daily gain (ADG) during prepartum (0.49 kg/d) than CON and SUP strategies (an average of 0.37 kg/d). Whereas ADG during postpartum was not altered by treatments. Considering the full cycle (prepartum and postpartum), supplementation strategies did not affect ADG and BCS. No differences were obtained for birth weight, weaning weight, and ADG in calves. Overall, the supplementation programs adopted in this study did not influence individual gains in both cow and calf. However, BW gain per area may be altered, since supplementation increases stocking rate.

52 Differences in body composition measurements for developing Angus heifers

Abstract The profitability of beef cow-calf operations relies on the reproductive ability of females to calve at 2 yr of age and provide a calf each subsequent year for her lifetime. The management of replacement heifers could affect her ability to conceive early, calve, and rebreed. Common management practices use heifer body weight (BW) (and body condition score (BCS) as indicators of puberty onset but do not indicate body composition and fat deposition. The objective of this study was to use ultrasound measurements of carcass traits to compare the effect of different diet management practices on muscle development and fat deposition of post-weaning heifers. The heifers placed on a higher energy diet are expected to have greater mean carcass trait measurements than the lower energy diet heifers. A total of 124 purebred Angus heifers from the Iowa State University McNay Memorial Research and Demonstration Farm were used for this study. Two diets were administered in this study. One group of heifers (G1; n = 61) was developed on a low-energy roughage diet to reach a target BW of 55% of mature BW at the time of breeding. The second group (G2; n = 63) was developed on a grain diet to reach the target BW of 65% mature BW at breeding. Body weight and ultrasound measurements for backfat (BFAT), ribeye area (REA), and intramuscular fat (IMF) were collected over three time points (0-d, 55-d, and 123-d) during the study to quantify the development of body composition characteristics. The initial measurements were collected 1 wk post-weaning. Significant mean differences between the two groups were observed for BW, BFAT, and REA at 55-d (P = 0.027, P = 0.008, and P < 0.0001, respectively), and 123-d (P < 0.001). The mean differences for BW, BFAT, and REA at 123-d between G1 and G2 were 30.98 kg, 0.10 cm, and 7.81 cm2, respectively No significant difference was found between the groups for IMF measurements at 55-d (P = 0.927) or 123-d (P = 0.169). This suggests IMF is not significantly influenced by diet during the early, post-weaning heifer developmental stage. Although further research is needed, the results from this study suggest the development of weight, BFAT, and REA in early post-weaning beef heifers is influenced by the energy concentration of the diet.

334 Metagenomic- and culture-based characterization of the ocular microbiome in cattle with infectious bovine keratoconjunctivitis

Abstract Pinkeye, clinically known as infectious bovine keratoconjunctivitis (IBK), is one of the most highly contagious diseases impacting cattle at all ages. Despite extensive use of antibiotics and vaccines targeting Moraxella bovis, the primary IBK pathogen, the incidence of pinkeye has been increasing in North American beef cow-calf operations. This highlights the incomplete understanding of the pathogenesis of this disease and the need for novel and alternative approaches to control IBK. The objectives of this study were to: 1) characterize the ocular microbiome of beef cattle with and without IBK using shotgun metagenomic sequencing; 2) investigate the genetic diversity of M. bovis, Moraxella bovoculi, and commensal ocular bacterial isolates; 3) evaluate whether selected ocular probiotic candidate strains inhibit Moraxella pathogen growth in the presence of the ocular microbiome in culture using qPCR. A total of 143 ocular swabs were collected from cattle with (n = 102) or without IBK (n = 42) and before antibiotic treatment from beef herds across North Dakota, USA. Fifty samples from IBK (n = 38) and healthy cattle (n = 12) were also subjected to shotgun metagenomic sequencing. Seven bacterial species were relatively more abundant (P < 0.05) in the healthy cattle ocular microbiome including Bifidobacterium globosum, Bacillus licheniformis, Pasteurella multocida, Ruminococcus sp900316555, and Ruminococcus sp900100595. Arthrobacter luteus was the only bacterial species significantly associated with IBK-affected cattle. From the metagenomes, 37 high-quality dereplicated metagenome-assembled genomes (MAGs) were recovered, nearly a third of which were identified as Mesomycoplasma bovoculi (n = 10). M. bovis (n = 5) and M. bovoculi (n = 13) were also isolated from the ocular swabs of both healthy and IBK-affected cattle. These isolates represented 9 M. bovoculi and 5 M. bovis strains (average nucleotide identity < 99.99%). We also isolated and sequenced several potentially beneficial bacterial species from healthy cattle including Bacillus pumilus, Lactiplantibacillus plantarum, Lentilactobacillus buchneri, Levilactobacillus brevis, and Weizmannia coagulans. Four of these probiotic candidates were also tested for their inhibitory effects against M. bovoculi in co-culture with the ocular microbiome after 24 h incubation using qPCR. The B. pumilus, L. buchneri, L. plantarum, and W. coagulans strains, as well as a mixture of all four isolates, significantly reduced the growth of Moraxella. In summary, our results provide important information on the culturable and non-culturable fraction of the bovine ocular microbiome potentially associated with IBK and suggest that certain bacterial species in the eye may inhibit the growth of Moraxella spp.

255 Awardee Talk: Nutritional management to optimize cow-calf production in Southeast

Abstract Nearly one-half of beef cows in the United States are located in southern states where cow-calf operations predominate. Grazing management in cow-calf systems can be affected by environmental and seasonal conditions, often leading to nutrient deficiency, particularly during late gestation of beef females. Maternal nutrition during the last trimester of gestation can influence offspring development and health, and can be explored to optimize maternal and progeny performance. The objective of this presentation is to share nutritional and management strategies for pregnant beef cows and their long-term effects on offspring growth and physiology. Study 1 investigated the effects of timing of maternal protein supplementation during all last trimester of gestation (LATE84), only the first 42 d of last trimester of gestation (LATE42), or no prepartum supplementation (NOSUP) on offspring pre- and post-weaning performance. At weaning, LATE84 calves were the heaviest, followed by LATE42, and NOSUP (P ≤ 0.05). Steer serum parainfluenza-3 titers were greater (P = 0.03) for LATE42 vs. NOSUP and tended to be greater for LATE84 (P = 0.10) vs. NOSUP steers. Marbling and the proportion of steers grading choice were greater (P ≤ 0.04) for LATE42 vs. NOSUP, and intermediate for LATE84. Study 2 evaluated the effects of frequency of maternal protein supplementation on offspring pre-weaning growth. Cows received the same weekly amount of supplement (7 kg·cow⁻¹·wk⁻¹) but with different frequencies: once a week (1X), three times per week (3X), every day (7X), or no prepartum supplementation (NOSUP) during the last 80 d of gestation. At weaning, calves born from 7X cows were the heaviest (P ≤ 0.05), followed by 3X and 1X, which did not differ between them (P = 0.54), and NOSUP calves were the lightest (P ≤ 0.05). Study 3 evaluated the use of monensin supplementation during the last 77 d of gestation and its impacts on offspring performance. Treatments consisted of no prepartum supplementation (NOSUP), supplementation of dried distillers grains at 1 kg·cow⁻¹·d⁻¹ added with 0 (SUP) or 200 mg/d of monensin (SUPMO). At weaning, SUPMO calves were the heaviest (P ≤ 0.05), SUP intermediate, and NOSUP were the lightest. Experiment 4 consisted of pregnant heifers receiving the supplementation of 1 kg/d of soybean hulls dry matter added (BAC) or not (CON) with a Bacillus-based DFM mixture during late gestation (d 0 to 139) and early lactation (d 139 to 242). Post-weaning body weight gain and indicators of humoral immune response post-vaccination were greater for BAC vs. CON calves (P ≤ 0.05). Therefore, changing the time and frequency of supplementation, and the use of additives and probiotics during late gestation of beef females are effective alternatives to improve offspring pre- and post-weaning growth and immune response.

Seasonal Patterns of Injury Characteristics Among Farmers and Ranchers in the U.S. Central States

ABSTRACT Objective In high-risk agricultural environments, tasks, weather, and work conditions vary throughout the year. Also, injuries peak during certain periods. The primary objective of this study was to examine operator- and farm-level characteristics as risk factors for injuries within each of the four seasons. The secondary objective was to examine seasonal differences in the incident location and primary cause of these injuries. Method We analyzed data from the 2018 and 2020 Farm and Ranch Health and Safety Surveys (FRHSS), conducted in seven U.S. states by the Central States Center for Agricultural Safety and Health (CS-CASH), which were collected using a stratified random sampling approach to ensure representativeness. The survey data were merged with operation-level data from the Farm Market iD database. We employed Generalized Estimating Equations (GEE) to examine the association of seasonal injuries with individual and operation-level characteristics. The chi-square test of independence was used to assess the association between injury incident location and season, as well as injury cause and season. Pairwise Z-tests of proportions were conducted to evaluate the differences in the proportions of injuries due to specific combinations of injury location and cause across each pair of seasons. Results Surveys conducted in 2018 and 2020 yielded a combined response rate of 15.9%, with 5,428 responses and 7,915 unique operators. Of these, 903 operators reported at least one injury during the past 12 months. Seasonally, most injuries occurred in spring (34.2%), followed by summer (24.7%). Male operators had higher injury odds in the spring (adjusted OR = 1.42) and summer (aOR = 2.41). Those managing both a farm and a ranch reported increased injury risks in winter (aOR = 1.73) and spring (aOR = 1.48). Operators in cow-calf operations faced higher springtime injury risks (aOR = 1.45). High stress and exhaustion were consistent risk factors across all seasons. The highest proportion of injury incidents occurred in the farmyard (43.6%), and livestock were the most common cause of injury (24.9%). Conclusion Results highlight the need for season-specific prevention and intervention strategies, considering farmers’ and ranchers’ risk characteristics, injury locations, and causes. These findings can inform targeted measures for high-risk populations at optimal times and locations.

Optimal Beef Cow Culling Strategies in the U.S.: A Dynamic Linear Programing Framework

AbstractThis study explores the economics of culling decisions in cow-calf operations in the Southern U.S. with a novel application of a dynamic mathematical programing model. The results provide an optimal culling strategy under the base model and a range of optimal strategies that vary with respect to different components such as fertility probabilities, prices, replacement costs, and pregnancy checking. The results suggest that producers should cull all cows that are older than age 10 and cows that fail to calve once they reach the age of 7. The sensitivity analysis underlines the impact of market conditions, replacement costs, and pregnancy check use on the optimal culling decisions.

Economic utility of Colombian Romosinuano cattle

The objective of this study was to quantify the economic utility in Romosinuano production systems by developing a bioeconomic model assumed cow-calf, cow-calf plus stocker (CCPS), and complete cycle operations. Each system produced males for sale and females for replacement. Input parameters were established from breed data collected by AGROSAVIA. Revenues were estimated using the official cattle price, and production costs were quantified per activity. In the results, for cow-calf operations, the maximum economic utility was 244.12 USD. CCPS, yielded 231.86 USD, and Complete cycle, 268.94 USD. The genetic progress per generation for W240, W480, W24 and CI was + 3.8 kg, + 5 kg, + 5.9 kg, and -1 d, respectively. The price of livestock was the sensitized variable with the greatest impact on maximum economic utility (± 118.64 USD to ± 155.44 USD), followed by mineral supplementation (16.31 USD to ± 37.34 USD). The sensitized variables with the lowest impact were food (± 1.62 USD to ± 1.8 USD) and health plan supplies (± 6.03 USD to ± 9.13 USD). It is concluded that economic utility defined as a composite trait influenced by the characteristics that shape it favors genetic progress and the identification of animals with optimal performance in different bovine production systems.

Soil legacy phosphorus and loss risk in subtropical grasslands

The accumulation of soil legacy phosphorus (P) due to past fertilization practices poses a persistent challenge for agroecosystem management and water quality conservation. This study investigates the spatial distribution and risk assessment of soil legacy P in subtropical grasslands managed for cow-calf operations in Florida, with two pasture types along the intensity gradient: improved vs semi-native pastures. Soil samples from 1438 locations revealed substantial spatial variation in soil legacy P, with total P concentrations ranging from 11.46 to 619.54 mg/kg and Mehlich-1 P concentrations spanning 0.2–187.27 mg/kg. Our analyses revealed that most of the sites in semi-native pastures may function as P sinks by exhibiting positive Soil P Storage Capacity (SPSC) values, despite having high levels of soil total P. These locales of higher SPSC values were associated with high levels of aluminum, iron, and organic matter that can adsorb P. In addition, our results from spatial random forest modelling demonstrated that factors including elevation, soil organic matter, available water storage, pasture type, soil pH, and soil order are important to explain and predict spatial variations in SPSC. Incorporating SPSC into the Phosphorus Index (PI) spatial assessment, we further determined that only 3% of the study area was considered as high or very high PI categories indicative of a significant risk for P loss. Our evaluation of SPSC and PI underscores the complexity inherent in P dynamics, emphasizing the need for a holistic approach to assessing P loss risk. Insights from this work not only help optimize agronomic practices but also promote sustainable land management, thus ensuring the long-term health and sustainability of grass-dominated agroecosystems.

CattleReview

Introduction: In this Cattle Review we consider two papers recently published in the same journal investigating cow-calf contact in dairy production and a paper looking at omphalitis in beef suckler (cow-calf) operations.

Practical guide to the bovine necropsy

Food animal veterinarians often have the opportunity to deter­mine the cause of death of bovine patients based on grossly vis­ible pathological changes alone, without the need for additional diagnostic testing. In some production systems (e.g., feedlot, stocker, and some cow-calf operations), a field necropsy is per­formed for almost every mortality; however, for one reason or another, some veterinarians and producers are reluctant to consistently take advantage of performing this procedure. The information collected from postmortem necropsies facilitates ongoing monitoring of disease rates in populations, feeds back into various animal health protocols, and guides decisions per­taining to disease outbreaks. Developing a standardized pro­cedure and employing the appropriate equipment can usually produce a diagnosis very quickly. Furthermore, with the imple­mentation of commonly used technologies, the same principles can be utilized to assist with expanding the geographic area in which diagnoses are made.

Trace mineral testing in Ontario cow-calf operations

There is much confusion surrounding trace mineral supple­mentation in cattle, particularly on cow-calf operations. Because a total mixed ration is rarely utilized, it can be chal­lenging to determine the amount of mineral that cattle are con­suming on a daily basis. When producers have health concerns in their herd that may be tied back to trace mineral consump­tion, the veterinarians struggle to determine if supplementa­tion was appropriate and which tests are the most effective to examine trace mineral status in the cows. The objective of this study was to examine the trace mineral status of cows on cow-calf operations in Ontario and understand more about the sup­plementation strategies that were being used.

Cow-calf chute side data collection in the field and its role in cow-calf consultation

Cattle Health and Reproduction LLC is a private vet practice located in the Snake River valley of Idaho servicing east Idaho and southwest Montana. It primarily serves beef cattle produc­ers with a major focus on large cow-calf operations with herds of 250 to 3,500 mother cows. The practice also services stocker/ yearling/feedlot operators and has a growing embryo transfer division. The practice retains a strong service-oriented approach with significant involvement in the herd management of its cli­ents. Data collection and information management has been a focus of the practice over the past couple of years and has aided in the development of a consultation leg of the practice.

An Evaluation of a Parenteral Antibiotic Treatment of Cattle with Non-Healing Claw Horn Lesions.

Non-healing claw horn disorders are a serious problem in dairy herds because of the long duration of the disorder and the chronic pain derived from it, seriously affecting animal welfare and causing decreased production and premature culling from the herd. In a clinical trial, 40 cows in 13 herds (12 dairy herds and 1 herd with cow-calf operations) with toe necrosis (TN, 27x) or a non-healing white line disorder (NHWLD, 13x) were treated topically with an unguent-containing zinc sulphate and acetyl acid in combination with a parenteral injection of tilmycosin. An evaluation was conducted 3 months after treatment using locomotion scoring (LS), a clinical observation of the lesion, and the lactation value (the lactation value is the Net Profit of the individual animal divided by the average Net Profit of the entire herd. The mean is 100, so >100 is related to better production (combination of kg milk, %fat, and protein)) (LV) before and after treatment. The mean LS improved significantly from 4.0 (SD: 0.2) before treatment to 1.2 (SD: 0.4) 3 months after treatment (p < 0.001). The clinical presentation showed that all of the cows were cured from horn shoe infection (both TN and NHWLD). The LVs of the treated cows increased significantly from 111.2 (SD: 12.2) to 116.8 (SD: 15.1; p = 0.003).

Grazing Management Plan Adoption and Objective Prioritization in U.S. Cow-Calf and Stocker Operations

AbstractThis study examines the grazing management plans (GMPs) adoption and prioritization of environmental and economic objectives among U.S. cow-calf and stocker operations, utilizing 2020–2021 survey data and logistic regression analysis. Findings reveal regional adoption differences, with higher rates in the Midwest. Operations with succession plans, larger grazing lands, and stocker activities are more likely to adopt GMPs. Operations with more privately owned land and smaller herd sizes prefer environmental goals, while those with less grazing land prioritize economic outcomes due to resource concerns. The study provides insights for policies promoting GMP adoption and sustainability in the U.S. beef sector.

Economic Analysis of Calving Assistance on Western Canadian Cow-Calf Operations

AbstractThe objective was to estimate the difference in cost, revenue, and profit between unassisted and assisted calvings on western Canadian cow-calf operations. Historical records of individual animal production measures from 2015 to 2020 and industry-described inputs were used in a modified decision tree model. The incidence of assisted calvings in heifers and cows was 4.6 and 2%, respectively. Assisted heifers and cows had an expected profit of −$227.43 and −$67.06 CAD per calving, respectively, while unassisted heifers and cows had an expected profit of −$76.11 and $120.12 CAD per calving, respectively. Calving assistance can impact the profitability of western Canadian cow-calf operations.

Optimizing ReBreed21 II: Fertility and reproductive efficiency in different parities during a shortened breeding season in beef cattle

This study evaluated the efficiency of a rapid reinsemination program allowing timed AI (TAI) every 21d (ReBreed21) in a commercial beef cow-calf operation. Nelore females from different parities (n = 2085) were synchronized for first TAI (D0 = TAI) using an estradiol/progesterone (E2/P4) protocol and assigned to one of three reinsemination programs: Resynch33 (n = 753), traditional resynch program with second TAI at D42 after first TAI; ReBreed21 (n = 687); or ReBreed21+EC (n = 670). The ReBreed females (n = 1357) received intravaginal P4 insert on D12, on D19 P4 was removed, and a dose of equine chorionic gonadotropin (eCG) was administered, then, ReBreed21 females received 0.6 mg of EC (ReBreed21+EC) or nothing (ReBreed21) and on D21, nonpregnancy (NP) was determined using Doppler ultrasound to detect corpus luteum (CL) blood flow (BF) (NP: <25 % BF pixels of total CL area) and NP cows received immediate TAI and GnRH to induce ovulation. Pregnancy diagnosis was performed at D33 after TAI following all TAIs. Cows considered pregnant at D21, based on CL BF, but NP on D33 were designated False-Positives (FP) and false negatives (FN) were number of nonpregnant cows/heifers on d21 based on the CL BF found to subsequently be pregnant on D33 divided by the total number pregnant. Pregnancy/AI (P/AI) did not differ for the first TAI (55.1 %) among the treatments. Heifers had similar P/AI at the second AI in all groups and similar to the first AI. Primiparous had greater P/AI in ReBreed21+EC and Resynch33 at s TAI compared to ReBreed21, 51.7 %, 55.8 %, 34.2 %, respectively. Multiparous had greater P/AI at second TAI in Resynch33 (60.9 %) than ReBreed21 programs (34.7 %). The percentage FP and FN among ReBreed21 programs did not differ, 13.8 and 0.2 %, respectively. Overall accumulative pregnancies on D21 of the breeding season were greater for ReBreed21 and ReBreed21+EC than Resynch33 (69.7 %, 71.6 %, and 55.5 %, respectively). However, on D42 of the breeding season, only heifers had greater pregnancies in ReBreed21 programs than Resynch33 (73.3 %, 74.3.6 %, and 63.2 %, respectively). Average days to pregnancy were less (P = 0.01) for ReBreed21 and ReBreed21+EC than Resynch33. Thus, the ReBreed21 strategy can improve the efficiency of TAI programs in beef cattle. Of interest, ReBreed21 was particularly effective in nulliparous, somewhat effective in primiparous when EC was added to the program, but relatively ineffective in multiparous beef cattle.

Combining Embryo Transfer and Artificial Insemination to Achieve Twinning in Beef Cattle, and Effects of Different Twin Calf-Raising Methods on Neonatal Behavior and Growth

As the beef industry moves towards efficient animal production to improve sustainability in agriculture, new production and management approaches are emerging. Among the many facets of the beef industry, cow–calf operations have the most opportunity for efficiency improvement, including improvements in fertility. This project accounts for measures and methods of (1) twinning reproductive technologies and (2) twin calf perinatal care and pre-weaning rearing. The overall objective was to produce twin calves using two reproductive technologies—embryo transfer and artificial insemination. The subobjectives were to determine accuracy of twin pregnancies embryo/fetal losses using ultrasonography, evaluate parturition and dystocia, and determine the effects of different twin-raising methods on neonatal behavior and growth. A fixed-time artificial insemination (FTAI) protocol was applied to 77 multiparous Angus-cross cows from a commercial beef herd in northcentral South Dakota during the summer of 2019. Cows were assigned to two different treatments groups: only artificially inseminated (AI) or received an embryo transfer following artificial insemination (ET + AI). They were estrous-synchronized, artificially inseminated (AI) with black Angus semen at day 0, and received and embryo transfer (ET) at day 7. Ultrasound examination detected 56% pregnancy risk for both groups, with sensitivity, specificity, and accuracy of 75%, 100%, and 90.5%, respectively, for bilateral twin detection. Calves were born during spring 2020. Twin calves (n = 34) and singleton calves (n = 11) were assigned to one of three raising methods: (1) twin born and twin raised (TT; n = 16), (2) twin born and single raised (TS; n = 18), and (3) single born and single raised (S; n = 11). Neonatal nursing behavior and birth weights were recorded, and adjusted day 200 and day 280 were calculated measures of vitality and growth. Blood samples were collected at age 24 h for colostrum intake measures (total serum protein, IgG1, and IgM). Twin calves were born 20% (p &lt; 0.05) lighter in body weight than singletons; however, weights did not differ at day 280 between TT and S calves. TS calves had the shortest average latency to stand, but immunoglobulin concentrations did not differ among treatments. At weaning, cows that had birthed and raised twins produced more kilograms of live weight per pregnancy than cows birthing and raising singletons. Using ET + AI proved to increase twinning rate, and growth was maintained when raising both twins with their dam.

Evaluation of risk factors of omphalitis in newborn beef calves with indoor housing

BackgroundOmphalitis is the third most common cause for diseases and infections in newborn calves. Its risk factors are well described in dairy production, but data in beef production is limited. ObjectiveTo identify and quantify the risk factors of omphalitis in cow-calf operations with seasonal indoor calving period. AnimalsNine hundred sixty-four calves included from 22 cow–calf operations in central France were included. MethodsA prospective cohort study involved data collection during two visits for each calf. Simple and multivariable logistic regression analyses evaluated the association between omphalitis and the variables. ResultsAmong 964 included calves, 311 (32.3%) calves had an omphalitis. Accounting for farms’ random effect, risk factors for omphalitis highlighted by the univariable analysis were: absence of navel disinfection (odds ratio (OR) = 2.3, [1.45–3.04]), wetness of bedding calving area (OR = 1.8–2.1, [0.78–2.83]-[0.63–3.57]), cleanliness of calves’ pen (OR =1.6–2.8, [1.22–2.27]-[2.02–3.84]), wetness of calves’ pen bedding (OR = 1.7–3.2, [1.12–2.06]-[3.08–3.84]), calf weight at birth >50 kg (OR = 2.0–5.0, [1.02–2.38]-[1.51–11.1]), umbilical cord length <3 cm (OR = 2.2–2.3, [1.53–3.11]-[1.24–4.38]), and sex (male vs female) (OR = 2.6, [2.08–3.69]). The multivariable analysis, accounting for farms’ random effect, showed that the absence of navel disinfection (OR= 2.2, [1.44–3.09]), wetness of bedding calving area (OR = 1.9–2.4, [0.55–2.83]-[0.59–3.28]), calf weight at birth >50 kg (OR = 1.9–2.6, [1.03–2.56]-[1.43–12.5]) and sex (male vs female) (OR =2.4, [2.09–3.49]) were risk factors for omphalitis. Conclusions and clinical importanceThese observations may help identify animals at early risk (>50 kg, male, short umbilical cord) and pay particular attention to the wetness of bedding and cleanliness of housing. This study highlights the importance of calving-pen bedding, calf characteristics and navel disinfection.

144 Utilizing invasive pigweed (Amaranthus Spinosus) as a novel methane mitigation strategy in beef cattle feed: A sustainable approach

Abstract By 2050, the US beef industry must produce an extra 40 million tons of beef to satisfy the global demand, while reducing methane (CH4) emissions. This surplus of cattle will be provided mostly by cow-calf operations, which rely primarily on grazing. Those pastures are often infested with weeds such as pigweed (Amaranthus spinosus), one of the most invasive in the US, known for its increased polyphenols concentration. Despite the known effect of polyphenols on CH4 reduction, few studies have explored pigweed as a feed additive. Our objective was to evaluate the effect of in vitro addition of pigweed on ruminal fermentation, digestibility, and CH4 production. We collected ruminal fluid from three American Aberdeen steers (374 ± 21 kg) receiving a backgrounding diet (80:20% corn silage:cotton gin trash, as fed). We incubated (24 h, 39°C) diet (0.7 g) plus the inclusion of 0, 2.5, 5, or 10% (of diet DM) of roots, stems, leaves, seeds, or the whole pigweed plant (WHO). Volatile fatty acids (VFA), CH4 (mmol g-1 organic matter), ammonia, pH, gas, in vitro dry matter, and organic matter digestibility (IVDMD and IVOMD) were determined. Using the MIXED procedure of SAS, data were analyzed as a randomized complete block design with a 5 × 4 factorial arrangement of treatments with plant part (n = 5) and inclusion level (n = 4) as fixed main factors. Incubation and bottle within incubation were random effects. Polynomial orthogonal contrasts were used to determine linear, quadratic, and cubic effects of inclusion level. Plant × level interactions were detected in acetate, propionate, and butyric molar proportion, total VFA, CH4 production, and IVDMD (P &amp;lt; 0.01). Increasing levels of stems increased acetate concentration (P = 0.03), while those from WHO led to a linear reduction of acetate (P &amp;lt; 0.01). The inclusion of 2.5% of leaves, seeds, and WHO increased propionate concentration (P = 0.05), but greater levels decreased it (P &amp;lt; 0.01). Increasing levels of all parts decreased acetate:propionate proportion (P &amp;lt; 0.001). Increasing levels of WHO resulted in a linear reduction of CH4 production (P &amp;lt; 0.05), while increasing inclusion of roots and stems increased CH4 production (P &amp;lt; 0.01). Quadratic reductions in CH4 production were observed after increasing the addition of leaves, seeds, and WHO (P &amp;lt; 0.001). Increasing levels of leaves and roots decreased ammonia concentration (P &amp;lt; 0.01) while stems increased it (P = 0.01). Except for stems and roots, there was a linear decrease in IVDMD with increasing levels of all parts (P &amp;lt; 0.001). The inclusion of low levels of seeds, leaves, and WHO promoted ruminal changes leading to a reduction of CH4 production without significantly compromising the digestibility.