Evaluation of the effects of corn silage maturity and kernel processing on steer growth performance and carcass traits.

Two experiments were conducted to investigate the effects of feeding kernel processed corn silage to growing calves at 65% inclusion (dry matter [DM] basis; Exp. 1] and finishing beef steers at 20% inclusion (DM basis; Exp. 2). In Exp. 1, steers (n = 184; initial shrunk body weight [BW] = 388 ± 22.3 kg) were used to evaluate the influence that kernel processing of corn silage has on production responses when fed at 65% diet inclusion (DM basis) during a 46-d growing period. Steers were allotted to 1 of 24 pens (12 replicate pens/treatment). Treatments were based upon corn silage that was either kernel processed or not. In Exp. 2, steers (n = 192; initial shrunk BW = 446 ± 28.3 kg) were used in a 112-d finishing experiment. Treatments were grouped in a 2 × 2 factorial arrangement (24 pens total; 8 steers/pen) to evaluate corn silage harvest maturity (1/2 to 2/3 milk line or black layer) and kernel processing (processed or not) at time of corn silage harvest on finishing steer growth performance and carcass traits when corn silage is fed at a dietary DM inclusion of 20%. Both experiments were analyzed as a randomized completed block design with pen as experimental unit. In Exp. 1, final BW tended (P = 0.07) to be increased by 3 kg in kernel processed corn silage. Daily weight gain and DM intake were increased (P ≤ 0.04) by 6% and 2%, respectively, in steers fed kernel processed corn silage compared to controls; however, gain efficiency was not appreciably influenced by treatment (P = 0.15). In Exp. 2, there were no harvest maturity × kernel processing interactions (P ≥ 0.26) for any growth performance measures or any parameters related to efficiency of dietary NE utilization. No harvest maturity × kernel processing interactions (P ≥ 0.08) were observed for any carcass traits except for the distribution of USDA Prime carcasses (P = 0.04). Steers fed 2/3 milk line and unprocessed corn silage had a lower (P = 0.05) proportion of carcasses grade USDA Prime (0.0%) compared to all other treatments (12.0%). Harvest time (P ≥ 0.07) and kernel processing (P ≥ 0.07) of corn silage had no appreciable influence on any other carcass trait measures. These data indicate that kernel processed corn silage fed to growing calves at 65% diet inclusion (DM basis) enhances intake and daily gain, while kernel processed corn silage fed to finishing steers at 20% diet inclusion (DM basis) does not appreciably influence daily gain, efficiency of gain, or carcass parameters.

Kernel processing of corn silage has yielded inconsistent results on diet digestibility and growth performance in beef cattle. These are likely a function of a variety of factors such as differing dry matter concentration of corn silage at harvest, diet inclusion levels, and length of cut. Two experiments were conducted to determine the effect that kernel processing of corn silage has on production responses in growing (65% dietary dry matter inclusion) and finishing beef steers (20% dietary dry matter inclusion). Data from the growing steer experiment when corn silage was included in the diet at 65% (dry matter basis) indicate that kernel processing of corn silage enhances dry matter intake and daily weight gain of beef steers with no appreciable influence on DM conversion efficiency. Data from the finishing steer experiment indicate that harvest maturity and kernel processing of corn silage have minimal effects on animal growth performance and carcass traits in finishing steers when corn silage is fed at 20% inclusion (dry matter basis). Variable responses could be related to differences in inclusion level, differences in effective roughage level fed, and a variety of other factors. Overall, these results suggest that corn silage fed to growing calves should be kernel processed to enhance dry matter intake and daily weight gain, while kernel processed corn silage fed to finishing steers does not appreciably influence daily gain, efficiency of gain, or carcass parameters.

Perceived Impact of the COVID-19 Pandemic on Physical Activity Among Adult Patients With Rheumatologic Disease.

OBJECTIVE: The objective of this cross-sectional study was to investigate the impact of the COVID-19 pandemic on physical activity (PA) levels of patients with rheumatic and musculoskeletal diseases (RMDs) and to examine factors associated with decreased PA. METHODS: A sample of adult patients with RMDs (n = 7,776) was identified through electronic medical records from an academic health care system in North Carolina. Invitations to participate in an online survey were sent between July 2020 and September 2020 to assess self-reported changes in PA during the COVID-19 pandemic. Descriptive statistics, age-adjusted prevalence odds ratios (PORs), and 95% confidence intervals (CIs) were computed to examine patient characteristics associated with decreased PA. RESULTS: A total of 893 eligible participants completed the survey (mean age 57.8 ± 14.9 years, 75.8% female). The most common primary diagnoses reported among participants included rheumatoid arthritis (27.3%), osteoarthritis (16.0%), and systemic lupus erythematosus (SLE) (13.0%). More than half of participants (56.8%) reported engaging in less PA since the pandemic began. Factors associated with engaging in less PA included lower self-reported general health (POR, 2.21; CI, 1.64-2.97) and a diagnosis of SLE (POR, 1.57; CI, 1.03-2.38). Comorbidities associated with decreased PA included chronic pain (POR, 1.38; CI, 1.04-1.82), depression (POR, 1.48; CI, 1.09-2.01), and hypertension (POR, 1.44; CI, 1.10-1.90). CONCLUSION: The COVID-19 pandemic has exacerbated barriers to PA in patients with RMDs. There is a critical need to provide resources, support, and multifaceted programs to encourage PA in patients with RMDs during the COVID-19 pandemic.

Reduced trabecular bone mineral density and thinner cortices in men with distal forearm fractures.

Men with distal forearm fractures have reduced bone density, an increased risk of osteoporosis and of further fractures. The aim of the study was to investigate the structural determinants of these observations using quantitative CT (qCT). Ninety six men with low-trauma distal forearm fracture and 101 age-matched healthy control subjects were recruited. All subjects underwent a quantitative CT on a standard 64-slice whole body CT scanner. These were analysed on Mindways QCT PRO™ Software to generate volumetric and geometric data at the lumbar spine, femoral neck and total hip, ultra-distal and distal 33 % radius. Biochemical investigations, health questionnaires and measurements of bone turnover were made. Men with fracture had significantly lower total and trabecular vBMD at all sites. The greatest percentage reduction was at the ultra-distal radius (13.5 % total and 11.7 % trabecular vBMD). In the fracture group cortical vBMD was significantly higher in the femoral neck (p < 0.001) and maintained at the ultra-distal radius compared with control subjects. However, cortical cross-sectional area (CSA) and thickness were significantly reduced at the femoral neck (p < 0.001 and p = 0.002 respectively) and forearm sites (CSA ultradistal radius p = 0.001, cortical thickness p = 0.002, CSA distal one third radius p = 0.045 and cortical thickness p = 0.005). Cross sectional moment of inertia (CSMI) and section moduli were significantly reduced at the femoral neck (CSMI1 p = 0.002, CSMI2 p = 0.012 and section moduli Z1 p < 0.001, Z2 p = 0.004) and the ultra-distal radius (CSMI1 p = 0.008 and section moduli Z1 p = 0.018, Z2 p = 0.007). In stepwise logistic regression analysis distal forearm fracture showed the strongest association with a model comprising ultra-distal forearm trabecular vBMD (negative), procollagen type I N-terminal propeptide (PINP, positive) and sex hormone binding globulin (SHBG, negative). In conclusion, these observations explain the structural reasons for the increased fracture risk in men with distal forearm fractures.

Modulation of expression of estrus, steroidogenesis and embryo development following peri-artificial insemination nutrient restriction in beef heifers.

Nutritional changes immediately after insemination cause increased embryonic mortality, but the mechanisms controlling this are not well known. Our objective was to evaluate the impact of nutritional change on estrus expression, steroid concentrations, peripheral and uterine luminal fluid metabolites, and embryo quality in beef heifers. Heifers (n = 139) were assigned to one of two pre-artificial insemination (AI) dietary treatments: LOW (≤ 90% NEm) or HIGH (≥ 139% NEm). Heifers were on treatment for 33-36 days before AI (d0) when half of the heifers in each treatment were randomly reassigned to generate four treatments; HIGH-HIGH, HIGH-LOW, LOW-HIGH, and LOW-LOW. Heifers remained on treatments until embryo collection (d 6-8). Negative energy balance was achieved among LOW heifers as demonstrated by body weight loss and increased NEFA concentrations (P < 0.05). Pre-AI treatment influenced expression of estrus (P = 0.05; HIGH 80.4 ± 4.0% vs. LOW 69.4 ± 4.2%). Estradiol concentrations and interval to estrus were not affected by treatment (P > 0.55); however, progesterone concentrations were reduced among LOW compared to HIGH (3.57 ± 0.27, 4.64 ± 0.26 ng/mL, respectively; P = 0.004), and heifers maintained on the HIGH pre-AI diet had consistently greater concentrations of progesterone from d 0 to d 8 (P = 0.014). Pre-AI treatment influenced embryo stage (P = 0.05; HIGH 3.61 ± 0.32 vs. LOW 2.72 ± 0.30). Post-AI treatment affected embryo grade (P = 0.02; HIGH 1.78 ± 0.23 vs. LOW 2.64 ± 0.27). In summary, pre-AI nutrient restriction caused decreased expression of estrus, reduced progesterone concentrations after AI, and negatively impacted embryo development, while post-AI restriction hindered embryo quality.

Proteomics dataset of epididymal fluid, seminal plasma, and proteins loosely attached to epididymal and ejaculated sperm from Angus bulls.

Peptides and proteins were identified by liquid chromatography with tandem mass spectrometry analysis (LCMS-MS) on an Orbitrap Velos mass spectrometer to further understand biological mechanisms that regulate increased longevity in epididymis compared to ejaculated sperm. Semen from sexually mature bulls were collected and then bulls were slaughtered to collect epididymal samples from the cauda epididymis. All samples were centrifuged to separate spermatozoa from fluids. A high ionic solution was used to remove surface proteins from spermatozoa. Four unique samples were generated: (1) epididymal fluid, (2) seminal plasma (ejaculated fluid), and proteins stripped from (3) epididymal sperm, and (4) ejaculated sperm. Samples were analyzed by LCMS-MS, and data were interpreted with Protein Pilot 5. False discovery rate (FDR) was set at 1%. Unique proteins (n = 458) were identified in ejaculated samples, 178 proteins in seminal plasma and 298 proteins stripped from ejaculated sperm. In epididymal samples, 311 proteins were identified in the fluid, and 334 were identified among proteins stripped from epididymal sperm. This dataset can be useful for further understand of biological mechanisms that control sperm longevity. This dataset is related to the article 'Proteomic analyses identify differences between bovine epididymal and ejaculated spermatozoa that contribute to longevity' by (Zoca et al., 2022).

Proteomic analyses identify differences between bovine epididymal and ejaculated spermatozoa that contribute to longevity.

Sperm are stored for extended periods of time in the epididymis, but upon ejaculation motility is increased and lifespan is decreased. The objective of this study was to identify differences in proteins between epididymis and ejaculated samples that are associated with longevity. Ejaculated semen was collected from mature Angus bulls (n = 9); bulls were slaughtered and epididymal semen was collected. Epididymal and ejaculated semen were centrifuged to separate sperm and fluid. Fluids were removed and sperm pellets were resuspended in a high ionic solution and vortexed to remove loosely attached proteins. Sperm samples were centrifuged, and the supernatant was removed; both fluid and sperm samples were snap frozen in liquid nitrogen and stored at -80 °C. Protein analysis was performed by LCMS/MS. A different group of yearling Angus cross bulls (n = 40) were used for sperm cultures. Ejaculated (n = 20) and epididymal (n = 20) semen were diluted and cultured in a commercial media at pH 5.8, 6.8 and 7.3, at 4 °C. Sperm were evaluated for motility and viability every 24 h until motility was lower than 20%. There was an effect of pH, time and pH by time interaction for motility and viability for both ejaculated and epididymal sperm (P ≤ 0.05). At 216 h of incubation epididymal sperm at pH 7.3 and ejaculated sperm at pH 6.8 reached motility below 20%. A total of 458 unique proteins were identified; 178, 298, 311, and 344 proteins were identified in ejaculated fluid, ejaculated sperm, epididymal fluid and epididymal sperm, respectively. There were 8, 24, 10, and 18 significant KEGG pathways (FDR <0.05) for ejaculated fluid, epididymal fluid, ejaculated sperm, and epididymal sperm, respectively. The metabolic pathway was identified as the most important KEGG pathway; glycolysis/gluconeogenesis, pentose phosphate, and glutathione metabolism pathways were significant among proteins only present in epididymal samples within the metabolic pathway. Other proteins identified that may be related to epididymal sperm's increased longevity were peroxidases and glutathione peroxidases for their antioxidant properties. In summary, energy metabolism in the epididymis appears to be more glycolytic compared to ejaculated and epididymis sperm have a larger number of antioxidants available which may be helping to maintain sperm in a quiescent state. Epididymal sperm remained viable (membrane integrity) longer than ejaculated sperm when cultured at the same pH.

Impact of trace mineral source on beef replacement heifer growth, reproductive development, and biomarkers of maternal recognition of pregnancy and embryo survival.

Trace minerals are known to play important roles in early embryo development. The study objective was to determine effects of trace mineral source on heifer reproductive performance. Beef heifers (n = 129) were randomly assigned to one of two treatments. From weaning through breeding, all heifers were individually fed a basal diet supplemented with cobalt (Co), copper (Cu), manganese (Mn), and zinc (Zn) either from organic sources (COMP; Cu, Mn, and Zn amino acid complexes and Co glucoheptonate; Availa-4, Zinpro Corporation, Eden Prairie, MN) or inorganic sources (INORG; Cu, Mn, and Zn hydroxychlorides; Intellibond C, M, and Z, Micronutrients, Indianapolis, IN) and Co as CoSO4. Blood samples and a reproductive tract score (RTS) were collected to determine pubertal status. All animals were synchronized and artificially inseminated. Pregnancy status was determined by lymphocyte gene expression, circulating concentrations of pregnancy-associated glycoproteins (PAGs), and by transrectal ultrasonography after artificial insemination. Embryonic loss was defined as when a previously pregnant animal was subsequently diagnosed not pregnant. Data were analyzed using the MIXED procedure in SAS. Puberty (P = 0.44), pelvic area (P = 0.74), RTS (P = 0.49), and estrus expression (P = 0.82) were not influenced by treatment. There was no effect of treatment (P = 0.37) or treatment by time (P = 0.19) on pregnancy, but there was a tendency (P = 0.13) for decreased embryonic loss among COMP heifers (27 ± 6%) compared to INORG heifers (38 ± 6%). There was a treatment by pregnancy status by time interaction (P < 0.01) on circulating PAG concentrations with PAG concentrations tending (P = 0.08) to be greater on day 25 among heifers in the COMP treatment compared to heifers in the INORG group. In summary, source of trace mineral did not affect puberty, RTS, pelvic area, or overall pregnancy success, but feeding complexed trace minerals tended to increase circulating PAG concentrations and embryo survival.

Evaluation of Bacillus subtilis PB6 on feedlot phase growth performance, efficiency of dietary net energy utilization, and fecal and subiliac lymph node Salmonella prevalence in spring placement yearling beef steers fed in southeastern South Dakota,.

Yearling crossbred beef steers [N = 238; initial shrunk body weight (BW) = 402 ± 31.2 kg] were used to investigate the influence of a Bacillus subtilis probiotic on animal growth performance, efficiency of dietary net energy (NE) utilization, carcass characteristics, and fecal and subiliac lymph node Salmonella prevalence during a 140-d finishing period at the Southeast Research Farm in Beresford, SD. Steers were allotted to 1 of 24 pens (N = 9-10 steers/pen) and assigned to 1 of 2 dietary treatments (12 pens/treatment): no probiotic (CON) or 0.5 g/steer/d of a B. subtilis PB6 probiotic (CLOSTAT500, Kemin Industries, Des Moines, IA; CLO). Bunks were managed according to a slick bunk management approach. Fecal samples were collected on study days 1, 28, 56, 112, and 140 from a subsample of steers from each pen (N = 5 steers/pen) via rectal palpation and composited by pen for the determination of Salmonella prevalence using selective enrichment and culture media. Upon harvest, subiliac lymph nodes were obtained from an equal number of steers from each treatment (collected from every other steer) following evisceration and hide removal. Data were analyzed as a randomized complete block design and pen served as the experimental unit; an α of 0.05 determined significance. Live-basis final BW and average daily gain tended (P ≤ 0.06) to be reduced for CLO. No differences were detected (P ≥ 0.11) between treatments for dry matter intake or gain efficiency. Treatment neither altered the efficiency of dietary NE utilization nor calculated dietary NE content based upon observed performance (P ≥ 0.46). No differences were detected between treatments for any carcass traits (P ≥ 0.15). No Salmonella was recovered in any fecal samples collected on study days 1, 28, or 56. On day 112, steers from CLO had a numerically lower (P = 0.17; 25.0 vs. 8.3%) incidence of fecal Salmonella compared to CON. On study day 140, fecal Salmonella incidence did not differ between treatments (P = 0.34; 0.0 vs. 8.3%) for CON and CLO, respectively. Upon harvest, no Salmonella was recovered in any subiliac lymph nodes. These data indicate that B. subtilis PB6 did not influence feedlot phase growth performance or fecal Salmonella prevalence. Additionally, Salmonella was not observed in the subiliac lymph nodes of any steers upon harvest.

Paget's Disease of the Bone: Patterns of Referral to Secondary Care Following Diagnosis on X-rays.

Paget's disease of bone (PDB) is the second commonest metabolic bone disorder in the UK after osteoporosis and is both underdiagnosed and undertreated. PDB is often found incidentally on plain X-rays. There is effective treatment so identification of affected individuals is important. The aim was to conduct an audit to determine what proportion of individuals with X-ray evidence of PDB were referred to secondary care. A retrospective audit of X-rays reports in men and women over 55 years of age was undertaken over 18 months searching for the key word "Paget's." The images of possible cases were reviewed and the presence of PDB confirmed. The proportion already known to secondary care was determined and those that had had isotope bone scans and treatment. Data recorded included site of lesion, age, gender, level of total alkaline phosphatase (ALP) and complications. A total of 68,873 X-rays were screened and 43 cases found. Pelvic images had the highest proportion of positive findings at 0.2% and 65% of the cases. 74% had not been referred to secondary care. The mean age was 86.7 years (range 65-95) and the ALP was elevated in 65% with a mean of 189u/L (range 47-804u/L). In 33 individuals, PDB had been recorded in the reports of previous X-rays. The rate of referral for specialist care remains low. The prevalence of the condition appears to be falling.

South Dakota State University Beef 2020 increases participant knowledge of the beef industry.

South Dakota State University has developed a hands-on program that addresses the preharvest management factors that influence beef carcass value to aid producers in their management and marketing decisions. The 3-d program includes live cattle and carcass evaluation, beef carcass fabrication, a harvest demonstration, sensory panel, and presentations on topics including live market cattle evaluation, health, and disposition in relation to carcass quality, feeding and management, and value-added beef cuts. To evaluate program effectiveness, data were collected from all programs held between 2013 and 2019. Participants were asked to evaluate their perceived value for each program component, as well as their knowledge of the industry prior to and after completing the program. Upon completion of the 2018 Beef 2020, a focus group of program alumni was assembled to better understand participant experiences, application of the material, and guide future programming. The recommendations of the focus group were implemented during the 2019 program. Component value scores are reported in a box and whisker plot and participant knowledge was evaluated using a paired t-test with significance determined at P < 0.05. Special attention was given to the results of 2019 compared to previous years to determine the efficacy of the program changes. Overall, the average value scores for the sessions all ranked above 8 on a scale of 1-10, indicating a relatively large value to participants. Knowledge of carcass traits, carcass value, and management factors that influence those traits increased after participation in the Beef 2020 program (5.18 vs. 7.67 ± 0.16; P < 0.0001). The use of a focus group was concluded to be an effective means of assessing program value, strengths, and weaknesses. The Beef 2020 program can be used as a model for other Extension professionals to create programs intended to link livestock producers to their end products.

Effect of progesterone supplementation in a resynchronization protocol on follicular dynamics and pregnancy success.

The objective of this study was to evaluate the necessity of a controlled internal drug releasing device (CIDR) in a fixed-time AI resynchronization protocol as well as to compare a commercially available blood pregnancy test with transrectal ultrasonography for Day 28 pregnancy detection. Over a two-year period, beef cows and heifers from twelve herds were inseminated using the 7-day CO-Synch + CIDR protocol. On Day 21 following the first insemination, the protocol was repeated, with animals receiving either a CIDR or no CIDR. Pregnancy status (AI1) was determined on Day 28 by both transrectal ultrasonography and the IDEXX Rapid Visual Pregnancy Test. Non-pregnant animals by both methods (CIDR: n = 190 cows, n = 228 heifers; no CIDR: n = 185 cows, n = 223 heifers) received an injection of Prostaglandin F2alpha and were inseminated at the appropriate time or bred following detection of estrus. Corpora lutea (CL) number and largest follicle diameter were recorded on a subset of non-pregnant animals (CIDR: n = 66 cows, n = 46 heifers; no CIDR: n = 76 cows, n = 41 heifers) at time of pregnancy diagnosis on Day 28. Final pregnancy status was determined a minimum of 31 days following the second AI (AI2). The GLIMMIX procedure of SAS was utilized for estrus and pregnancy data; while the MIXED procedure was utilized for analyses of CL number and largest follicle diameter. There was no effect (P ≥ 0.55) of treatment on AI1 pregnancy, AI2 pregnancy, or overall pregnancy rates. The presence of a CIDR during the resynchronization increased (P < 0.001) estrus expression prior to AI2. There was an effect of treatment by age on AI2 pregnancy (P < 0.01); heifers that received a CIDR had greater AI2 pregnancy rates than heifers that did not receive a CIDR (P = 0.04), but there was no difference between cows with and without a CIDR. Treatment had no effect (P > 0.10) on embryonic loss (between the first and second pregnancy diagnosis), CL number, or follicle diameter. Although, there was a tendency for the interaction of treatment by age on follicle size (P = 0.07), with cows having larger follicles than heifers in the no CIDR group but not the CIDR group. In conclusion, use of a CIDR in this resynchronization protocol increased estrus expression, increased AI2 pregnancy for heifers, but did not improve pregnancies in cows, and did not influence overall pregnancy or embryonic loss.

Effect of inclusion rate of silage with or without alpha-amylase trait on finishing steer growth performance, carcass characteristics, and agronomic efficiency measures.

One hundred ninety-two Continental × British steers [initial body weight (BW) = 420 kg (standard deviation = 24.7)] were used in a randomized complete block design finishing study to evaluate the effects of feeding two types of silage germplasm at two inclusion rates. A 2 × 2 factorial arrangement of treatments was used with either a conventional hybrid (Golden Harvest G07B39-311A, Syngenta Seeds LLC, Minnetonka, MN; CON) or a hybrid with increased expression of alpha-amylase (Syngenta Enogen Feed corn, Golden Harvest E107B3-3011A-EVT5, Syngenta Seeds, LLC; ENO) fed at either 12% (12SIL) or 24% (24SIL) of diet dry matter. Steers were blocked by source and location (source 1: first three pen replicates, n = 10 steers per pen with a fourth pen replicate of six steers per pen; source 2: one pen replicate, n = 12 steers per pen) and assigned randomly within block to treatments, resulting in five pens and 48 steers per treatment. Steers were harvested after 126 (12SIL) or 140 (24SIL) days on feed (DOF). There were no silage hybrid by inclusion rate interactions detected for live growth performance (P ≥ 0.15). Silage hybrid did not affect average daily gain (ADG), gain-to-feed ratio (G:F), or final BW (FBW; P ≥ 0.35). Feeding 24% silage reduced ADG (P = 0.04) and increased G:F (P = 0.01) but increased FBW (P = 0.02) because of greater DOF compared with 12SIL. A hybrid by inclusion rate interaction was detected (P = 0.04) for calculated yield grade (YG) with steers fed 24SIL having increased YG within CON but not ENO. Hot carcass weight and rib fat were unaffected by silage hybrid (P ≥ 0.81) but were increased by feeding 24SIL (P = 0.03 and P = 0.02, respectively). Feeding increased amounts of silage increased beef produced per hectare (P = 0.05). Source of silage did not affect feedlot growth performance of cattle but, because of slight differences in estimated silage yield, conventional silage produced more kilograms of beef per hectare (P < 0.01). Feeding increased amounts of silage reduced G:F on both a live and carcass-adjusted basis but increased kilograms of beef produced per unit of land, which is paramount to cattle feeders who grow their own feedstuffs.

Influence of Sexcel™ (gender ablation technology) gender-ablated semen in fixed-time artificial insemination of beef cows and heifers.

Previous research has indicated that gender-sorted semen has decreased conception rates compared to conventional semen. A new method to skew the gender ratio of semen has been developed that does not use traditional sorting technology. Thus, the objective of this study was to evaluate the use of gender-ablated semen in a fixed-time AI protocol. Beef heifers and cows (n = 878) from six herds were synchronized with the 7-d CO-Synch plus CIDR protocol, and artificially inseminated (AI) after CIDR removal (cows 60-66 h; heifers 52-56 h). Estrus detection aids were applied at CIDR removal and estrus activity was determined at time of AI. Animals remained separated from bulls for at least 10 d after AI. Pregnancy success and fetal age were determined between d 28 and 70 after AI. Semen from five sires was utilized in this study, with two sires used in each herd. Sire 1 was used in all herds and the use of the second sire varied by herd (both conventional and gender-ablated semen from each sire was used in each herd). Data were analyzed using the GLIMMIX procedure in SAS and included the influence of semen type, estrus expression, semen type by estrus expression, dam age, and sire in the model. Herd was included as a random variable. Overall, conventional semen had greater conception rates compared to gender-ablated semen (P < 0.01; 67% vs 52%), and cows that had fully activated patches and partially activated patches had greater conception rates compared to animals that had not exhibited estrus (P < 0.01; 69%, 65%, and 45%). There was no semen type by estrus expression interaction (P = 0.24). Conception rates tended to be greater for conventional semen among animals that had activated patches (P = 0.06; 73% vs 65%) and partially activated patches (P = 0.06; 72% vs 59%). Conception rates were greater for conventional semen (P < 0.01; 56% vs 33%) among animals that did not exhibit estrus. There was no effect of dam age (P = 0.40) or sire (P = 0.92) on conception rates. In conclusion, Sexcel™ gender-ablated semen can successfully be used in fixed-time AI protocols among animals that exhibit estrus, but caution should be used among animals that do not exhibit estrus.

Estimates of diet selection in cattle grazing cornstalk residues by measurement of chemical composition and near infrared reflectance spectroscopy of diet samples collected by ruminal evacuation.

Six ruminally cannulated cows (570 ± 73 kg) fed corn residues were placed in a 6 × 6 Latin square to evaluate predictions of diet composition from ruminally collected diet samples. After complete ruminal evacuation, cows were fed 1-kg meals (dry matter [DM]-basis) containing different combinations of cornstalk and leaf and husk (LH) residues in ratios of 0:100, 20:80, 40:60, 60:40, 80:20, and 100:0. Diet samples from each meal were collected by removal of ruminal contents after 1-h and were either unrinsed, hand-rinsed or machine-rinsed to evaluate effects of endogenous compounds on predictions of diet composition. Diet samples were analyzed for neutral (NDF) and acid (ADF) detergent fiber, acid detergent insoluble ash (ADIA), acid detergent lignin (ADL), crude protein (CP), and near infrared reflectance spectroscopy (NIRS) to calculate diet composition. Rinsing type increased NDF and ADF content and decreased ADIA and CP content of diet samples (P < 0.01). Rinsing tended to increase (P < 0.06) ADL content of diet samples. Differences in concentration between cornstalk and LH residues within each chemical component were standardized by calculating a coefficient of variation (CV). Accuracy and precision of estimates of diet composition were analyzed by regressing predicted diet composition and known diet composition. Predictions of diet composition were improved by increasing differences in concentration of chemical components between cornstalk and LH residues up to a CV of 22.6 ± 5.4%. Predictions of diet composition from unrinsed ADIA and machine-rinsed NIRS had the greatest accuracy (slope = 0.98 and 0.95, respectively) and large coefficients of determination (r2 = 0.86 and 0.74, respectively). Subsequently, a field study (Exp. 2) was performed to evaluate predictions of diet composition in cattle (646 ± 89 kg) grazing corn residue. Five cows were placed in 1 of 10 paddocks and allowed to graze continuously or to strip-graze corn residues. Predictions of diet composition from ADIA, ADL, and NIRS did not differ (P = 0.99), and estimates of cornstalk intake tended to be greater (P = 0.09) in strip-grazed compared to continuously grazed cows. These data indicate that diet composition can be predicted by chemical components or NIRS by ruminal collection of diet samples among cattle grazing corn residues.

Comparison of fertility of liquid or frozen semen when varying the interval from CIDR removal to insemination.

Cryopreservation allows for long-term storage of semen; however, it leads to damage of sperm that may result in complete loss of viability or changes that possibly decrease sperm functionality. Liquid semen is not exposed to these stressors and may result in a longer lifespan in the female reproductive tract, thus increasing the range in timing of insemination without affecting fertility. The objective of this study was to compare fertility of liquid and frozen semen when varying the interval from CIDR removal to AI using the 7-day CO-Synch+CIDR protocol for synchronization of time of estrus. Within age group, crossbred cows (n=389) were randomly assigned to insemination at 36 or 60h after CIDR removal with either liquid or frozen semen (36L, 60L, 36F, and 60F) from one of two Angus bulls. Cows were monitored for estrous activity from CIDR removal until 60h thereafter. Cows that failed to exhibit estrus received GnRH (100µg, i.m.), and a blood sample was collected for analysis of estradiol concentration. There was no difference in pregnancy rates when liquid or frozen semen (53% and 52%) was used, but cows inseminated at 60h had a greater (P<0.01) pregnancy rate than those inseminated at 36h (72% and 31%). There was no time of AI by semen type interaction (P=0.57). Estrus was detected in 63%, 61%, 56%, and 62% of 36F, 36L, 60F, and 60L, respectively (only 5% and 1% of 36F and 36L were detected in estrus before insemination). Overall cows that exhibited estrus had a greater pregnancy rate compared with cows that did not (P<0.01; 79% compared with 24%). Among cows that did not exhibit estrus, those inseminated with liquid semen tended to have greater pregnancy rates than those inseminated with frozen semen (P=0.06). Cows that became pregnant had greater (P<0.01) concentrations of estradiol at 60h than those that did not (10.7±0.55 compared with 7.9±0.26pg/mL). In summary, there was no difference in pregnancy success between liquid and frozen semen. However, cows that exhibited estrus and were inseminated at 60h after CIDR removal had greater pregnancy success compared to cows that did not exhibit estrus.