Beef Cows Research Articles

Social interactions and movement patterns of rangeland-raised beef cows and their calves

Understanding the spatial and temporal relationships between beef calves and their dams is crucial for effective rangeland management. This study investigated these dynamics on semiarid rangeland using GPS collars fitted on cow-calf pairs. Data were collected on 46 crossbred cows and 34 calves grazing two adjacent 219 and 146 ha pastures. The primary objective was to determine the proximity of calves to their dams and other adult cows at different calf ages (1, 2 and 4 mos.). Over a 24 h period, calves spent on average 10.5 and 17.5 h within 5 or 10 m of an adult cow, respectively, and spent 2.6, 5.6 and 2.3 h within 5 m of their dams, other adult cows and a guard cow (cow other than the dam that spent the most time in the proximity of a calf), respectively. Calves spent more time within 5 or 10 m of an adult cow during night vs. daytime hours and spent detectably (P < 0.05) more time within 5 or 10 m of other adult cows vs. their dam (5.6 vs. 2.6 or 10.3 vs. 3.5 h). Calves spent a similar (P > 0.05) amount of time within 5 or 10 m of their dam vs. the guard cow (2.6 vs. 2.3 or 3.5 vs. 3.7 h) regardless of age during both day and nighttime hours. In general, calves spent more time within 5 and 10 m of an adult cow at 2 vs. 1 or 4 mos. of age. Greater mother-offspring clustering occurred at 2 vs. 1 or 4 mos. of age regardless of the spatial threshold considered. Regardless of calf age, calves and nursing cows traveled on average 4.5 and 6.7 km/day, respectively. Calves at 4 mo of age traveled farther than younger calves. Nursing cows traveled farther when calves were 4 mo. vs. 1 or 2 mos. of age and tended to travel farther when calves were 1 vs. 2 mos. old. Calves spent more time close to other nursing cows vs. their dam. These findings suggest that while dams play a crucial role in calf development, other nursing cows may also influence their foraging behaviors. Further research is needed to fully understand the dynamics of these relationships and their implications for rangeland management, such as optimizing grazing strategies and improving calf health and productivity.

A review and future trends of precision livestock over dairy and beef cow cattle with artificial intelligence

Abstract The demand for meat and dairy products is expected to rise significantly in the current demographic and economic growth context. Concurrently, various factors, including financial crises and reduced profitability, have decreased the number of livestock farms. Consequently, the livestock industry is undergoing intensification, with an increased number of cows per farm. This shift makes the management of animals increasingly complex. Amid these challenges, the society’s growing concern for animal health and welfare and the quality of consumed products underscores the importance of systems that aid in the individual and herd-level monitoring and control within livestock operations. In this scenario, precision livestock farming has become essential with the emergence of new sensors and technologies and the evolution of artificial intelligence. Against this backdrop, this paper reviews systems and techniques used in precision livestock farming to detect anomalies caused by reproductive processes and diseases in dairy and beef cattle. The article analyzes sensors and technologies employed, presents key studies conducted, and discusses the most commonly used artificial intelligence techniques in detecting prevalent anomalies.

Seasonal environmental fluctuations alter the transcriptome dynamics of oocytes and granulosa cells in beef cows

BackgroundExamining the mechanistic cellular responses to heat stress could aid in addressing the increasing prevalence of decreased fertility due to elevated ambient temperatures. Here, we aimed to study the differential responses of oocytes and granulosa cells to thermal fluctuations due to seasonal differences. Dry beef cows (n = 10) were housed together, synchronized and subjected to a stimulation protocol to induce follicular growth before ovum pick-up (OPU). Two OPU’s were conducted (summer and winter) to collect cumulus-oocyte-complexes (COCs) and granulosa cells. In addition, rectal temperatures and circulating blood samples were collected during OPU. Oocytes were separated from the adherent cumulus cells, and granulosa cells were isolated from the collected OPU fluid. RNA was extracted from pools of oocytes and granulosa cells, followed by library preparation and RNA-sequencing. Blood samples were further processed for the isolation of plasma and leukocytes. The transcript abundance of HSP70 and HSP90 in leukocytes was evaluated using RT-qPCR, and plasma cortisol levels were evaluated by immunoassay. Environmental data were collected daily for three weeks before each OPU session. Data were analyzed using MIXED, Glimmix or GENMOD procedures of SAS, according to each variable distribution.ResultsAir temperatures (27.5 °C vs. 11.5 °C), average max air temperatures (33.7 °C vs. 16.9 °C), and temperature-humidity indexes, THI (79.16 vs. 53.39) were shown to contrast significantly comparing both the summer and winter seasons, respectively. Rectal temperatures (Summer: 39.2 ± 0.2 °C; Winter: 38.8 ± 0.2 °C) and leukocyte HSP70 transcript abundance (Summer: 4.18 ± 0.47 arbitrary units; Winter: 2.69 ± 0.66 arbitrary units) were shown to increase in the summer compared to the winter. No visual differences persisted in HSP90 transcript abundance in leukocytes and plasma cortisol concentrations during seasonal changes. Additionally, during the summer, 446 and 940 transcripts were up and downregulated in oocytes, while 1083 and 1126 transcripts were up and downregulated in the corresponding granulosa cells, respectively (Fold Change ≤ -2 or ≥ 2 and FDR ≤ 0.05). Downregulated transcripts in the oocytes were found to be involved in ECM-receptor interaction and focal adhesion pathways, while the upregulated transcripts were involved in protein digestion and absorption, ABC transporters, and oocyte meiosis pathways. Downregulated transcripts in the granulosa cells were shown to be involved in cell adhesion molecules, chemokine signaling, and cytokine-cytokine receptor interaction pathways, while those upregulated transcripts were involved in protein processing and metabolic pathways.ConclusionIn conclusion, seasonal changes dramatically alter the gene expression profiles of oocytes and granulosa cells in beef cows, which may in part explain the seasonal discrepancies in pregnancy success rates during diverging climatic weather conditions.

Silvopastoral systems as a strategy to attenuate the negative effects of heat stress on productivity of beef cows grazing natural grassland

Silvopastoral systems as a strategy to attenuate the negative effects of heat stress on productivity of beef cows grazing natural grassland

New Aspects of Mortellaro’s Disease: A Literature Review

Introduction. All over the word, hoof diseases, and Mortellaro’s disease in particular, are being among the most widespread and difficult to treat diseases in dairy cattle husbandry. They cause irreparable economic damage to the dairy industry by reducing the cattle reproductive ability indicators, feed conversion ratio, which compels to spend considerable amounts on treatment, prevention and culling of animals. Mortellaro’s disease is especially widespread in Europe and Western countries, but the current rate of national economy growth leads to the necessity to purchase the cattle abroad, which results in the increase of the Mortellaro’s disease incidence in Russia: at the farms where cattle has been imported, the percentage of the disease is 14.17±5.15% of the total number of hoof diseases in the herd. The aim of this review is to summarise the results of scientific research on the Mortellaro’s disease pathogenesis over the past 20 years.Materials and Methods. To achieve the stated objective, the criteria of inclusion into the search were defined. It was decided to include in the review the studies/reports presenting the results on: 1) the disease etiology and factors affecting the course of Mortellaro’s disease; 2) symptoms of Mortellaro’s disease manifestation in different species of farm animals; 3) the methods of Mortellaro’s disease treatment. The materials published in Elsevier, ASM Journal, Irish Veterinary Journal, Thieme, American Dairy Science Association, Epidemics, Schweiz Arch Tierheilkd, Journal of Clinical Microbiology, eLIBRARY.RU, Google Scholar have been investigated in the frame of the literature search. The search by the following keywords was done: interdigital dermatitis, Mortellaro’s disease, hoof diseases of cattle, contagious interdigital dermatitis. The time range of sources – those published within the period from 2003 to 2023.Results. In total, 44 articles have been analysed, 33 of which have been included in the present review. According to the studied materials, one of the prerequisites underlying the spread of Mortellaro’s disease in the Russian Federation is the import of the infected cattle, since the measures undertaken during the temporary housing and quarantine periods do not give the desired result. The animals get infected with the bacteria of the genus Treponema, which are localized deep in the hoof tissues, therefore, after the disease is endured, it turns into its chronic form. The specific symptoms of Mortellaro’s disease course in various cattle breeds have been established: in beef cows and buffaloes the interdigital dermatitis is characterised by a low level of pain symptom severity; in sheep – by the ulcerative lesions of the сoronary band, which progress and lead to the destruction of the abaxial hoof wall and loss of the hoof horn. The areas with the erosion are very painful, but the intercellular adhesive junctions are not lost, which allows for positive prognosis of the disease. The main indicators of productivity and fertility are reduced due to the disease, as is the immunity in general, and there is an estrous cycle delay. In the samples of patients sick with the digital dermatitis, an increase of the number of intact and degranulated mast cells is observed, compared to the healthy ones, which indicates that mast cells can play an important role in the pathogenesis of digital dermatitis. Nowadays, the Mortellaro’s disease treatment abroad and in Russia is based on the elimination of symptoms, and not the pathogen itself. The local treatment is mainly represented by the antiseptic baths, surgical treatment, local application of antibiotics to the wound. The experiments on antibiotic susceptibility of Treponema, which are the important step in the search for the specific treatment of Mortellaro’s disease, have been performed. The antibiotic susceptibility tests gave positive results (all isolates of Treponema were sensitive to tiamulin, valnemulin, tylosin, aivlosin, lincomycin, doxyclin), however, the difficulty lies in the method of drug administration into the source of Treponema localization, since the conventional ways of administration of antibiotics entail restrictions on the sale of milk and meat.Conclusion. The presented review of the scientific publications on Mortellaro’s disease made it possible to summarise the currently known results and identify the areas for further research. For example, it should be still investigated why the interdigital dermatitis requires the presence of many Treponema species rather than one? What role do representatives of the Mycoplasma, Porphyromonas and other bacteria play in the pathogenesis of the studied disease? And of course, there is a serious scientific gap in finding treatment of Mortellaro’s disease capable of eliminating the pathogen itself, rather than its symptoms. It should be mentioned that not all Treponema species can be cultivated, which also slows down the scientific process and makes the problem of Mortellaro’s disease treatment relevant worldwide.

Seminal plasma uterine priming alters uterine transcriptomics and negatively impacts embryo growth and uterine artery resistance but not offspring liver transcriptomics in beef cattle.

Seminal plasma uterine priming is important for pregnancy and offspring phenotype in mice and swine; however, impacts on the uterus of the dam and her offspring in cattle are unknown. We sought to determine the effects of seminal plasma uterine priming at estrus on uterine transcriptomics, early gestation (d 35, 40, and 45) embryo morphometrics, mid- to late-gestation (d 140 to 220) uterine artery hemodynamics, birth morphometrics, and liver transcriptomics in offspring at 30 d of age. Multiparous Angus-based commercial beef cows were randomly assigned to receive treatment at estrus: 0.5mL pooled seminal plasma in the uterine body (n = 31, seminal plasma primed) or no treatment (n = 31, control). Seven d later a subset of cows (n = 4/treatment) underwent uterine biopsies, and the remaining cows underwent embryo transfer. Embryo crown-rump length and uterine artery hemodynamics were measured during gestation using ultrasonography. Morphometrics of the calf were collected within 24h of parturition. Liver biopsies were collected at 30 d of age. Data were analyzed by ANOVA in a completely randomized design for the effect of treatment. Myosin heavy chain I (JSP.1) was downregulated [Benjamin-Hochberg adj P (BH) <= 0.05] and ABO alpha 1-3-N-acetylgalactosaminyltransferase and alpha 1-3-galactosyltransferase (ABO) was upregulated (BH adj P <= 0.05) in the uterus of seminal plasma primed cows 7 d after treatment. Embryo crown-rump length was less (P < 0.05) in seminal plasma primed cows. Mid- to late-gestation (d 140 to 220) uterine artery resistance was increased (P < 0.05) in seminal plasma primed cows. Seminal plasma priming did not alter birth weights or curve-crown-rump length, but heart girth was increased (P < 0.05) in offspring from seminal plasma primed cows. There were no differentially expressed genes (BH adj P <= 0.05) in offspring liver at 30 d of age; however, myosin light chain, phosphorylatable, fast skeletal muscle (MYLPF) was absent in all liver samples from calves from seminal plasma primed cows. In contrast, vomeronasal 1 receptor bosTauV1R414 (BOSTAUV1R414) was present in 6 of the 7 liver samples from calves from seminal plasma primed cows. Seminal plasma uterine priming alters uterine transcriptomics, negatively impacts early gestation embryo growth and mid- to late-gestation uterine artery resistance suggesting downstream vascular anomalies. However, these in utero conditions did not impact offspring from birth to 30 d of age.

Analysis of Factors Affecting Beef Cattle Business Income (Case in Cipari Village, Cigugur District, Kuningan Regency)

The purpose of this study is to find out the factors that affect the income of beef cattle business in Cipari Village, Cigugur District, Kuningan Regency. This research was carried out at the Beef Cattle Farm Owned by Cipari Village, Kalibaru Village, Cigugur District, Kuningan Regency, West Java Province. The time of this research will be carried out in May - July 2024. The method in this study uses a quantitative descriptive method with a survey approach. The sampling technique in this study is to use saturated sampling (census). The sample in this study is all cattle breeders in Cipari Village consisting of 17 farmers with the ownership of 2 to 4 beef cattle. The Data Analysis Techniques carried out in this study include descriptive analysis quantitative, i.e. Multiple linear regression analysis. The results of the study show that (1) The number of beef cattle, the selling price of livestock, the labor cost factor, the price of beef cattle, the feed price factor, and the price of medicines, simultaneously have a significant effect on the income of the beef cattle business in Cipari Village, Cigugur District, Kuningan Regency; (2) The most influential factor on the income of the beef cattle business is the Number of Beef Cow Factor, because the number of beef cattle has the most significant influence on income.

Bovine abortion caused by leptospirosis

AbstractA 3‐year‐old, 255 kg, mixed breed beef cow has an abortion at the last trimester of gestation, approximately 8 months. The cow was from a 1200‐hectare farm, with 1200 animals. The farm owner reported a total of 13 abortions between June and September 2022, all of them in the last trimester of gestation. Additional serological screening for Leptospira was performed in 40 cows from the herd by microscopic agglutination test with seropositive animals to serovars Icterohaemorrhagiae. Gross postmortem examination yielded icterus, pleural and peritoneal effusions. Histopathological findings were lymphoplasmacytic interstitial pneumonia and nephritis, with intraluminal spirochetes within the renal tubules, hepatic necrosis, and cholestasis. PCR on a fresh tissue pool was positive for Leptospira spp. (LipL32). Leptospirosis is a zoonotic disease, caused by the infection of the bacterial spirochetes belonging to the genus Leptospira spp. Serovars Pomona and Icterohaemorrhagiae cause acute systemic leptospirosis in cattle after incidental infections due to poor husbandry conditions and cause abortion loss in cattle in occasional outbreaks.

PSV-25 Investigating the effects of Chromium Propionate supplementation on productive and reproductive performance of beef cows

Abstract We investigated the effects of Chromium Propionate supplementation on reproductive performance of beef cows from pre-partum to weaning. Suckled beef cows at nine locations were enrolled in the study. Within location, cows were stratified by parity, dam age, and day postpartum (DPP) and randomly assigned to one of two treatments: 1) Control, supplementation of a mineral product at 113 gּ animal-1ּ d-1 (n = 464 cows; 13 experimental units); or 2) CrP, supplementation of mineral product at 113 gּ animal-1ּ d-1 containing 1.4 g of Chromium Propionate (0.4%KemTRACE Chromium 0.4%, Kemin Industries, Inc., Des Moines, IA; n = 489 cows; 13 experimental units). Treatments were initiated at approximately 37 d pre-calving until weaning for a total of 250 ± 12 d. Cows were enrolled in the 7-d CO-Synch+CIDR fixed-time artificial insemination (TAI) protocol followed by natural service for a 70-d breeding season. Pregnancy diagnosis was performed by ultrasonography at 55 d after TAI protocol and 40 d after the end of the breeding season. Cow body weight (BW) and body condition score (BCS) were recorded at initiation of the TAI protocol (d -10), at pregnancy diagnosis (d 55 and 110), and at weaning (d 285). Within group, mineral disappearance was determined by the difference in weight between offered mineral and refusals. Data were analyzed using the GLIMMIX and MIXED procedures of SAS with pasture/group as the experimental unit with the effect of treatment and included group (treatment × location), cow (group), and location as random variables. Age, DPP, d -10 BCS, and BW were similar (P &amp;gt; 0.05) between treatments (5.4 and 5.3 ± 0.61 yr, 79.2 and 79.9 ± 4.61 d, 5.1 and 5.2 ± 0.05, 515.7 and 515.6 ± 15.11 kg for Control and CrP, respectively). Mineral disappearance was similar (P = 0.999) between treatments (165.5 and 152.9 gּ animal-1ּ d-1, for Control and CrP, respectively). Cow BW was similar (P &amp;gt; 0.05) between treatments on d 55, 110 and 285 (558.5 and 551.4 ± 14.50 kg, 580.8 and 594.6 ± 13.51 kg, and 574.2 and 570.9 ± 14.32 kg for Control and CrP, respectively). Similarly, cow BCS did not differ (P &amp;gt; 0.05) between treatments on d 55, 110 and 285 (5.4 and 5.4 ± 0.09, 5.3 and 5.3 ± 0.10, and 5.1 and 5.2 ± 0.10 for Control and CrP, respectively). Calf birth and weaning BW were similar (P &amp;gt; 0.05) between treatments. However, CrP-supplemented cows tended (P = 0.081) to have greater estrus expression (60.2 and 68.3 ± 3.1 %, for Control and CrP, respectively) and CrP-supplemented cows had greater (P = 0.045) TAI pregnancy rate when compared with Control cows (49.9 and 55.2 ± 2.1 %). Supplementation of Chromium Propionate to beef cows from pre-partum through weaning did not affect cow BW and BCS, tended to increase estrus expression and increased TAI pregnancy rate.

PSXII-26 The influence of protein supplementation in beef cows during early lactation on growth performance, carcass characteristic and meat quality of progeny

Abstract At 11 ± 4 d of lactation, 30 multiparous Angus cows [body weight (BW) = 476 ± 17 kg, body condition score (BCS) = 4.5 ± 0.3) were stratified by BW and allotted in 6 pens (5 cows/pen). During 75 d of experiment, all pens received ad libitum low quality hay (Panicum italicum; 54.7% TDN, 6.1% CP DM basis) and were randomly assigned to one of two treatments: 1) PS; cows received ad libitum 30% CP supplement including an intake limiter component (Controlmix, Nutralmix SRL, Argentina), or 2) NS; cows were not supplemented. After the experimental period, dams and their calves (PS: 7 males and 8 females; NS: 8 males and 7 females) were managed on improved pastures as a single group until weaning at 213 d of age. After weaning, heifer and steer calves were reared on improved pastures until 448 d of age, then placed into a feedlot with a finishing diet during 73 d until slaughter. Pens were considered the experimental unit and data were analyzed using the PROC MIXED of SAS, considering treatment and sex as a fixed effects and pen as a random effect. Overage dry matter intake (DMI) of hay was not affected by treatments (P &amp;gt; 0.10), and DMI of supplement in PS cows was 4.4 kgּ cow-1ּ d-1. Milk production was greater in PS than NS cows (PS: 5.3, NS: 3.6 kgּ cow-1ּ d-1; P &amp;lt; 0.01). Progeny from PS cows increased BW at weaning (PS: 180, NS: 141 kg; P &amp;lt; 0.01), BW at initial feedlot phase (PS: 300, NS: 252 kg; P = 0.01) and final BW (PS: 415, NS: 354 kg; P = 0.01). After slaughter, progeny from PS cows tended to have increased dressing percentage (PS: 59.0, NS: 58.1%; P = 0.09), had an increased hot carcass weight (PS: 227, NS: 191 kg; P &amp;lt; 0.01), and increased Longissimus muscle (LM) area (PS: 68.5, NS: 60.1 cm2; P = 0.02), while rib fat thickness was not affected by treatments (PS: 7.8, NS: 7.6 mm; P = 0.68). There was no effect of protein supplementation on color (L*, a*, b*) and pH of LM at 24 h postmortem (P &amp;gt; 0.10). In addition, moisture, ether extract and shear force of LM after 4 d of aging were similar between treatments (P &amp;gt; 0.10). There was no treatment × sex interaction for any variables (P &amp;gt; 0.10). This study showed that protein supplementation during early lactation improved growth performance and carcass quality, but did not result in enhanced meat quality of progeny.

PSVII-30 Winter-feeding high concentrate diets reduces enteric methane emissions pre-calving in beef cows

Abstract Objectives were to evaluate the effects of winter-feeding forage (2.02 Mcal/kg dietary ME) vs. concentrate (2.84 Mcal/kg of dietary ME) diets pre- and post- calving on enteric methane emissions, dry matter intake (DMI), and performance of beef cows. Forty-six pregnant (210 ± 10 d of gestation) Angus and Simmental-Angus cows [n = 46; body weight (BW) = 630 ± 12.0 kg) were blocked by breed, age, and BW and assigned to one of two treatments: 1) Ad-libitum feeding of forage-based diet (HFOR; n = 23); or 2) a concentrate corn-based diet with a restricted intake of 1.2% BW (HCON; n = 23). Cows were housed in a group-pen at the South Dakota State University Cow-Calf Education and Research Facility (Brookings, SD). Feed consumption was tracked using an electronic feeder (Insentec, The Hague, Netherlands) and enteric methane emissions were monitored using the GreenFeed trailer system (C-Lock Inc., Rapid City, SD). Body weight measurements were taken bi-weekly. Treatments started being applied on d 50 (± 10) pre-calving and will continue to be applied up to d 84 post-calving. Preliminary data reported herein was collected from d 42 pre-calving up to d 42 post-calving. Performance and dry matter intake data were analyzed as repeated measures using the MIXED procedure of SAS with treatment, period, and their interaction as fixed effects and animal as a random effect. Enteric emissions were analyzed using a linear mixed effects model with animal as a random effect in R, with a post-hoc contrast among treatments. Pre-calving, HFOR had greater (P &amp;lt; 0.01) CH4 emissions than HCON (264 ± 9.19 g/d and 246 ± 9 g/d for HFOR and HCON, respectively). Both groups presented dynamic changes in CH4 emissions over time (P &amp;lt; 0.01). Post-calving, no differences were observed between treatments (P = 0.55); however, temporal changes (P &amp;lt; 0.01) and treatment × d interaction (P &amp;lt; 0.01) persisted, indicating ongoing diet-temporal interplay. No treatment × period interactions (P ≥ 0.16) were observed for DMI and performance. As designed, dry matter intake was less (P &amp;lt; 0.01) for HCON (8.66 ± 0.45 kg) than HFOR (17.3 ± 0.45 kg) cows. Further, dry matter intake was less (P &amp;lt; 0.01) pre-calving (11.11 ± 0.28 kg) than post-calving (14.85 ± 0.48 kg). Cows in the HFOR group were heavier (P = 0.01) than HCON (646.22 ± 14 kg vs. 593.43 ± 14 kg, respectively) likely due to ruminal fill; and as expected cows were heavier (P &amp;lt; 0.01) pre- than post-calving, with the greatest BW observed on d 14 pre-calving (639.52 ± 9.92 kg). These data indicate that high concentrate corn-based diets may be used in dry-lot settings to optimize nutritional management and reduce methane emissions when compared with conventional high forage winter-feeding strategies.

PSLBI-12 Screening and isolation of Fusobacterium necrophorum and Fusobacterium varium from seminal, and vagino-uterine microbiota of healthy cattle and sheep

Abstract Fusobacteria necrophorum is an important opportunistic bacterial pathogen associated with liver abscesses, foot rot, necrotic laryngitis and endometritis in both dairy and beef cattle. Recently, we identified F. necrophorum as one of the taxa in the uterine microbiota that are positively associated with pregnancy outcome in beef cows, and that Fusobacterium was identified as the most dominant genus in the bovine seminal microbiota. These findings indicate that Fusobacterium spp. may have a role in reproductive health and cattle fertility. Our objectives were to detect and isolate the F. necrophorum subsp necrophorum (FNN), F. necrophorum subsp. funduliforme (FNF) and F. varium (FV) in seminal, vaginal and uterine microbial ecosystems as well as fetal samples by culture and real-time PCR (qPCR) methods. The qPCR was performed on the DNA (n = 215) extracted from bull semen (n = 37), ram semen (n = 100), and vaginal (n = 25) and uterine swabs (n = 32), caruncles (n = 9), allantoic fluid (n = 6), and amniotic fluid (n = 6) from pregnant beef cows. The qPCR targeted the hgdA gene, and leukotoxin promoter regions (lktA-n and lktA-f) to detect and quantify FV, FNN and FNF, respectively. Cryopreserved samples (n = 174; 57 bull semen, 10 ram semen, 38 vaginal, and 47 uterine swabs) were cultured to detect and isolate FNN, FBF and FV by direct plating and after culturing in anaerobic peptone-yeast extract broth containing sodium lactate broth with josamycin, vancomycin and norfloxacin for selective enrichment of FN and FV. Also, 28 samples of 6-mo-old bovine fetuses caruncles, allantoic and amniotic fluids, and intestinal tissue) were screened for Fusobacterium species. By qPCR, FNF was detected in 75.7% of bull semen, and 8.0% of vaginal swabs as well as 33.3% of both allantoic fluid and caruncles, but was undetected in ram semen, uterine swabs, and amniotic fluids. Subspecies necrophorum was identified in 37.8% of bull semen, 3% of ram semen, 8.0% of vaginal and 15.6% of uterine 55.6 % of caruncles, 50% of allantoic fluid samples, but was not detected in amniotic fluid samples. Meanwhile FV was only detected in vaginal, uterine swabs and caruncles at 4%, 6.3%, and 11.1%, respectively. The culture method detected FNF in 63.2% of bull semen and 5.3% of vaginal samples, while FNN was identified in 1.8% of bull semen and 2.1% of uterine samples. F. varium was not isolated from any of the samples. Overall, FNF was the most prevalent subspecies present in the seminal microbiome of bulls. Identification of FNN subspecies and FV in seminal, vaginal, and uterine microbiota of healthy cattle, as well as in healthy calf fetus-associated samples suggests potential transfer from bulls to cows and then on to offspring, and potential involvement of the Fusobacterium spp. in cattle fertility.

PSVI-22 Effects of supplementation of beef cows during gestation on progeny backgrounding frame size and performance

Abstract The implications of supplementation during gestation on growth and efficiency of offspring have gained interest worldwide. The hypothesis of this study was that supplementation of cows during gestation results in favorable progeny growth and nutrient utilization. Our objectives were to assess the impacts of providing supplementation to pregnant beef cows during the dry grazing period on progeny backgrounding performance. During a 2-yr period, Tabapuã cows (n = 36) were managed on Brachiaria pastures, which were assigned to 1 of 3 treatments as follows: no application of N on pasture and cows supplemented with mineral mix (CON), 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), and application of 165 kg of Nּ ha-1ּ yr-1 and cows supplemented with grass silage (GS). At the beginning of the dry period, 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. Bull (n = 18 in yr 1 and 12 in yr 2) and heifer progeny (n = 13 in yr 1 and 17 in yr 2) were weaned with average age of 203 ± 18 d in yr 1 and 229 ± 15 d in yr 2. After weaning, progeny were weighed and allocated in individual pens and adapted to a growing diet over 90 in yr 1 and 89 d in yr 2. For both years, rations were formulated to provide 0.9 kg/d (Dietary NEm = 1.68 Mcal/kg and dietary Neg = 1.07 Mcal/kg, on average). The PROC MIXED procedure of SAS was used to analyze all variables. The statistical model included supplementation program as a fixed effect and sex (male or female) as a random variable. Initial BW, weaning age, estimated progeny difference, and d on feed were included as covariates. No differences were obtained for initial BW, final BW, ADG, DM intake, and G:F. Frame size (e.g., heart girth, hip height) was also unaffected by dam supplementation. Overall, supplementing pregnant beef cows, during the dry grazing period, with a commercial supplement or silage does not affect progeny performance during backgrounding.

PSV-16 Evaluation of upper respiratory and fecal microbiomes in neonatal beef calves

Abstract There is a critical lack of information on the timing of colonization of bovine respiratory disease-related bacteria in the upper respiratory tract, potentially affecting calf health and disease onset. The objective of this study was to evaluate the upper respiratory tract and fecal microbiomes of neonatal beef calves during the first 24 h of life compared with their dams at the time of birth. Late-gestation commercial beef cows (n = 28) were assigned to individual, soil-surfaced pens (6.25 x 2.29 m) fitted with canvas tarps on shared fences to limit contact between unrelated pairs. Left nasal (LN), right nasal (RN), fecal, and vaginal swab samples were collected from cows at a single time point promptly after parturition. Swabs of the LN, RN, and rectum were collected from calves at birth (0 h), 6, 12, and 24 h post-parturition. Samples were flash-frozen and stored at -80°C until processing. DNA was extracted from swabs using Power Soil Pro kit. Extracted DNA was used to prepare DNA libraries for full-length 16S rRNA gene sequencing on a MinION Mk1C device. Sequenced reads were classified using Centrifuge and used in microbiome analyses conducted in R to estimate the changes in the microbiome according to animal type (cow versus calf), time of collection, and sample type (nasal, fecal, or vaginal). Upper respiratory microbiomes significantly differed (P &amp;lt; 0.005) between cows and their offspring at birth. In nasal microbiomes, animal type explained 12.6% (P = 0.002) and 18.5% (P = 0.001) of variance in beta diversity in left and right cavities, respectively. Animal type explained 42.1% of the beta diversity variance in fecal microbiomes (P = 0.001). Nasal microbiomes at birth were significantly more dispersed in dams compared with their calves in both the LN (P = 0.03) and RN (P = 0.03). Similarly, fecal microbiomes of dams were significantly more dispersed (P &amp;lt; 0.0001) than those of their offspring. There was a clear transition of the microbial communities associated with calf age in the upper respiratory and fecal niches. Calf age accounted for 2% (P = 0.02), 3.5% (P = 0.001), and 28% (P = 0.001) of the variance in the beta diversity of the LN, RN, and fecal microbiomes, respectively. After adjusting for calf age, the laterality of nasal microbiomes was not significantly (P = 0.682) associated with the composition of microbial communities. In conclusion, calf microbial communities were dissimilar to that of their dam at birth. Additionally, microbial community transition was evident with each subsequent sampling time point, potentially influenced by the presence of the dam.

PSVI-3 Finishing-based diets degradability of beef cows supplemented with a Bacillus-based probiotic

Abstract Probiotics, sometimes referred to as direct-fed microbials (DFM), are live microorganisms that, when given in sufficient quantities, confer health benefits to livestock animals. Research has indicated that probiotics based on Bacillus enhance the dry matter and neutral detergent fiber digestibility of various feed sources, animal feed, and commercial total mixed rations (TMRs) in vitro. Given that, the aim of this study was to evaluate the influence of a Bacillus-based probiotic supplementation on nutrient degradability of commercial finishing-based diets. Ruminally fistulated Angus × Hereford cows (n = 15; 6.1 ± 1 yr of age; body weight = 658 ± 57) were used in complete randomized designs and housed in individual pens with water, and forage intake monitored daily. Treatments consisted of 1) 500 g of protein supplement (dry distillers grain + mineral mix) without probiotic (CON n = 8), and 2) 500 g of protein supplement + 3 g of a probiotic containing Bacillus licheniformis and B. subtilis (BOV; n = 7; 2.2 ×109 CFU of the mixture/g; Bovacillus, Novonesis, Hørsholm, Denmark). The experimental period lasted 33 d, consisting of 21 d of adaptation and 12 d of collection. From d 28 to 32, four different commercial finishing diets (4 g; Table 1) were fitted in Dracon bags and incubated in the rumen for 0, 12, 24, 48, 72, and 96 h in reverse order so that all bags were removed at the same time and immediately washed until clear water was obtained. After washing, the bags were dried at 56 ºC for 72 h to determine the dry matter. Subsequently, the NDF and ADF content was determined. A treatment effect was detected (P ≤ 0.05) for dry matter degradability in 3 out of 4 finishing-based diets used herein, which increased by approximately 4% in cows supplemented with BOV vs. CON. Supplementing beef cows with BOV also enhanced (P ≤ 0.05) neutral detergent fiber degradability by 12.1, 22.3, and 24.0% in finishing diets A, B, and C, but not D (P = 0.52), compared with CON cows, respectively (Table 2). Cows receiving BOV had greater (P = 0.04) acid detergent fiber degradability in finishing diet A and a tendency (P = 0.07) for finishing diet C compared with CON cows, whereas acid detergent fiber degradability was similar (P ≥ 0.13) among treatments for finishing diets B and D. In conclusion, Bacillus-based products could be used as a nutritional alternative tool to increase nutrient degradability of finishing-based diets.

107 Intrauterine infusions of Flunixin Meglumine on gestational day 30 resulted in pregnancy loss in beef cows

Abstract The physiological mechanisms underlying late embryonic/early fetal mortality in beef cows are largely unknown. Our lab, as well as others, have documented that cows undergoing late embryonic mortality have significantly decreased circulating concentrations of prostaglandin F2a metabolite (PGFM) and increased concentrations of prostaglandin E2 metabolite (PGEM) during gestational d 30 to 38, coinciding with the time of active placentation. Thus, the overall objective of this study was to analyze the physiological effect of inhibiting local prostaglandin synthesis during late embryonic development in beef cows. To determine the appropriate dosage and drug required for the sufficient knockdown of uterine-derived prostaglandins, three pilot studies were conducted. In pilot study one and two, indomethacin was administered intravenously or intrauterine into cyclic cows at a dose of 80 mg/d (n = 4) or, 160 mg/d (n = 4), directly into the jugular of pregnant cows at a dose of 270 mg/d (n = 1) or directly into the uterine artery of pregnant cows at a dose 360 mg/d (n = 2). Administration of indomethacin did not significantly knockdown PGFM or PGEM (P &amp;gt; 0.05). However, in pilot study three, a 720 mg/d dose of flunixin meglumine (FM; Banamine, Merck Animal Health, NJ) infused intrauterine into cyclic beef cows (n = 5) resulted in a treatment by day interaction (P &amp;lt; 0.001) in which luteolysis in treatment cows was inhibited as well as the synthesis of both prostaglandin F2a and prostaglandin E2. Following this validation, the next study was performed using multiparous beef cows that were subjected to a 7-d CO-Synch + CIDR synchronization protocol with insemination occurring on d 0. Pregnancy was confirmed by the presence of a fetal heartbeat on d 28 via ultrasonography and subsequent blood collections every 8 h via venipuncture (n = 9). Intrauterine infusions began on d 29 and occurred every 8 h via infusette catheter consisting of either 240 mg of FM diluted in 10 mL of flush media (ABT; FMTrt; n = 6), or 10 mL of flush media (CON; n = 3). Both infusion solutions were corrected to a pH of 7.4. Serum concentrations of PGFM were measured with a validated commercial ELISA (Cayman Chemical, MI). Though all cows were confirmed pregnant on d 28, concentrations of PGFM were significantly greater on d 28 (P &amp;lt; 0.01) and d 29 (P &amp;lt; 0.05) in the FMTrt cows than the CON cows. There was a significant decline in circulating PGFM within the FMTrt cows (P &amp;lt; 0.05) post infusion on d 29. After two infusions, CON cows had significantly greater PGFM concentrations compared with the FMTrt group (P &amp;lt; 0.01). By d 30, after three infusions, all FMTrt cows had terminated their pregnancies; however, CON cows maintained their pregnancies. Perhaps, these data indicate the importance of prostaglandins during this critical period of pregnancy. Further research is required to fully understand the physiological contribution that prostaglandins elicit in regard to pregnancy.

Metabolic and productive adaptive response of beef cows to successive short-nutritional challenges

This study aimed to analyze the response of lactating beef cows to repeated short nutritional challenges with their performance parameters and plasma metabolites. Multiparous lactating beef cows were subjected to three repeated nutritional challenges in the fourth month of lactation. Each challenge consisted of a 4-d feed restriction (55 % of their average energy and protein requirements), followed by a 3-d refeeding period (100 % requirements). Cows were classified into two groups differing in their performance (milk yield) and metabolic adaptation [non esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB)] to diet changes (metabolic response, MR): High and Low MR cows, where the High MR cows showed a faster and larger response to diet changes than the Low MR cows (P < 0.001). The loss in milk yield during restriction was the smallest in challenge 1 (P < 0.001). Milk urea increased during restriction in challenges 1 and 2 (P < 0.001). The High MR cows had greater NEFA concentrations than their Low MR counterparts during restrictions, and greater BHB concentrations during the restriction of challenge 2 (P < 0.001). Restriction increased NEFA, BHB (only in the High MR cows) and urea (P < 0.01). During refeeding, both milk yield and plasma metabolites recovered basal values (P > 0.05). These results highlight the ability of beef cows to respond to and recover from successive short-term nutrient restrictions, and that despite a certain degree of sensitization of milk yield may have occurred, there were only minimal changes in the metabolic strategies triggered to cope with repeated underfeeding.

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.

100 Impact of luteal blood perfusion and estrus expression on pregnancy rates of beef cows exposed to embryo transfer

Abstract This study aimed to evaluate the impact of luteal blood perfusion and estrus expression on pregnancy rates of beef cows exposed to fixed-timed embryo transfer (FTET). Postpartum beef cows (n = 763) from 22 locations were exposed to a 7-d Select Synch + controlled internal drug releasing (CIDR) and breeding indicator patches were affixed upon CIDR removal. Estrus expression was assessed twice daily for 72 h and a 100-µg injection of gonadotropin-releasing hormone was administered to cows that failed to express estrus 72 h after CIDR removal. Brightness mode ultrasonography of the corpus luteum (CL) was conducted to select recipients for FTET 9 d after CIDR removal. Suitable recipients were assigned to receive a single fresh or frozen embryo derived from either in vitro (IVF) or in vivo (IVD) method. After embryo recipient selection, CL morphometries and blood perfusion (BP) were then assessed at the time of embryo transfer via transrectal ultrasonography. Embryo recipients were categorized according to CL area [small (&amp;lt; 3 cm²), medium (3 to 4 cm²), or large (&amp;gt; 4 cm²)] and based on the percentage of luteal area with blood perfusion signals [low (&amp;lt; 25%), medium (25 to 45%), or high (&amp;gt; 45%)]. Pregnancy diagnoses were performed between d 60 and 90 of gestation. Cows that failed to express estrus prior FTET had decreased (P ≤ 0.02) luteal area, luteal diameter, and pregnancy rates compared with cows that expressed estrus. Luteal area category had no effect (P = 0.61) on pregnancy rates. Embryo recipients that expressed estrus had similar (P = 0.12) luteal blood perfusion compared with recipients that failed to express estrus. Embryo recipients with high (P = 0.02) and medium (P = 0.05) BP had greater pregnancy rates compared with embryo recipients with low BP. There was no interaction between estrus expression and luteal BP (P = 0.84). In summary, estrus expression and luteal BP positively impacted pregnancy rates to embryo transfer and may be used to facilitate embryo recipient selection.

232 Influence of melatonin supplementation on uterine and coccygeal artery hemodynamics of pregnant multiparous crossbred beef cows grazing endophyte-infected tall fescue

Abstract The objective was to determine the influence of melatonin supplementation on uterine and coccygeal artery hemodynamics of pregnant beef cattle grazing toxic, endophyte-infected (E+) tall fescue during mid-late gestation. Multiparous crossbred cows were artificially inseminated with sex-sorted semen (Y chromosome-bearing sperm) from a single Red Angus sire and maintained on pastures free from E+ fescue prior to the start of the treatment period. Pregnant cows (n = 50) were assigned to one of three treatment groups with two replications per treatment: non-toxic, novel endophyte-infected (NE+) fescue without melatonin supplementation (NE+/NM; n = 16), E+ fescue with melatonin supplementation (E+/M; n = 16), and E+ fescue without melatonin supplementation (E+/NM; n = 18). Treatments were administered over a 70-d period between May and July (d 147 ± 1 to 217 ± 1 of gestation). A commercially available feed was mixed with or without melatonin [100 µg/kg body weight (BW)] and hand-fed daily. Cows were weighed at d 0, 14, 28, 42, 56, and 70 relative to the start of the treatment period. Measures of uterine and coccygeal artery hemodynamics included artery diameter, pulsatility index (PI), resistance index (RI), blood flow (BF), and blood flow as a proportion of BW (BF/BW) and were determined by color Doppler ultrasonography at the conclusion of the 70-d treatment period. Plasma prolactin was determined at the end of the 70-d treatment by radioimmunoassay. After the treatment period, cattle were maintained together as a single group on pastures that were free from E+ fescue. Body weights were analyzed using the MIXED procedure of SAS specific for repeated measures with treatment, time, and the interaction as fixed effects and replicate as random. Prolactin and arterial hemodynamics were analyzed using the MIXED procedure of SAS with treatment as a fixed effect and replicate as random. There was an effect of time and a treatment by time interaction on cow BW (P &amp;lt; 0.01). Prolactin was decreased (P = 0.02) in E+/NM (71.8 ± 14.0 ng/mL) and E+/M (86.9 ± 14.9 ng/mL) relative to NE+/NM (128.9 ± 14.9 ng/mL) cows. Coccygeal artery PI was decreased (P &amp;lt; 0.02) in E+/M (0.86 ± 0.1) relative to NE+/NM (1.06 ± 0.1) cows. Coccygeal artery RI was decreased (P &amp;lt; 0.01) in E+/M (0.53 ± 0.02) relative to NE+/NM (0.62 ± 0.02) cows. There were no other effects of treatment (P &amp;gt; 0.05). Preliminary results suggest limited effects of melatonin on uterine and coccygeal artery hemodynamics in pregnant multiparous crossbred beef cows grazing endophyte-infected tall fescue.