Browsing by Author "Hall, John B."

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    Body Condition Scoring Beef Cows
    Eversole, Dan Edward; Browne, Milyssa F.; Hall, John B.; Dietz, Richard E. (Virginia Cooperative Extension, 2009-05-01)
    Body condition scoring uses a numeric score to estimate body energy reserves in the cow. Research indicates that there is a strong link between the body condition of a cow and her reproductive performance.
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    Body Condition Scoring Beef Cows
    Eversole, Dan Edward; Browne, Milyssa F.; Hall, John B.; Dietz, Richard E. (Virginia Cooperative Extension, 2005-09-01)
    Body condition scoring uses a numeric score to estimate body energy reserves in the cow. Research indicates that there is a strong link between the body condition of a cow and her reproductive performance.
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    Calm Temperament Improves Reproductive Performances of Beef Cows
    Whittier, William Dee; Kasimanickam, Ramanathan K.; Assay, M.; Schroeder, S.; Kasimanickam, Vanmathy R.; Gay, John M.; Hall, John B. (Virginia Tech. Powell River Project, 2015)
    Profitability of a beef operation is determined by breeding season pregnancy rates and proportion of cows attaining pregnancy early in the breeding season. Many factors including temperament contribute to these reproductive parameters. The objective of this study was to evaluate the effect of temperament on reproductive performances of beef cows. In experiment 1, Angus and Angus cross beef cows (n=1546) from 8 locations received body condition score (BCS; 1-emaciated; 9-obese) and chute-exit and gait score (1 = slow exit, walk; calm temperament; 2 = jump, trot or run; excitable temperament). Cows were grouped with bulls (1:25 to 1:30; with satisfactory breeding potential and free of venereal disease) during the entire 85 day breeding season. Pregnancy status and gestation length of cows was determined by per-rectal palpation at 35 days after the end of the breeding season. Controlling for BCS (P<0.01) and handling facility (P<0.0001) and handling facility by temperament score interaction (P<0.001) the breeding season pregnancy rate was different between excited and calm cows [88.6% (798/901) vs. 94.1% (607/645); P<0.001]. Cows with excitable temperament took 24 more days to become pregnant in the 85 day breeding season compared to calm cows (median days to pregnancy: 35 vs. 59 days; P<0.0001). In experiment 2, Angus and Angus cross beef cows (n=1407) from 8 locations received body condition score (BCS; 1-emaciated; 9-obese) and chute-exit and gait score (1 = slow exit, walk; calm temperament; 2 = jump, trot or run; excitable temperament). All cows were grouped with bulls (1:25 to 1:30; with satisfactory breeding potential and free of venereal disease) during the entire 85 day breeding season. Pregnancy status was determined by per-rectal palpation at 2 and 6 months from the beginning of the breeding season to determine the pregnancy loss. Controlling for BCS (P<0.05), the pregnancy loss was different between excited and calm cows, 5.5 (36/651) vs 3.2 (20/623), respectively (P<0.05) In conclusion, beef cows with excitable temperament had lower reproductive performance than calmer cows. The modified 2-point chute exit-gait scoring method is repeatable and can be used to identify cattle with excitable temperament.
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    Calving Emergencies in Beef Cattle: Identification and Prevention
    Whittier, W. Dee; Currin, Nancy; Currin, John F.; Hall, John B. (Virginia Cooperative Extension, 2005-09-01)
    Calving difficulty, technically called dystocia, is a major cause of death loss in cow-calf herds. Studies indicate that dystocia is responsible for 33 percent of all calf losses and 15.4 percent of beef cattle breeding losses.
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    Cattle Identification: Freeze Branding
    Hall, John B.; Greiner, Scott P.; Gregg, Cynthia L. (Virginia Cooperative Extension, 2005-09-01)
    Freeze branding offers a permanent form of individual animal identification that is easy to read at a great distance, causes minimal damage to the hide, and is less painful than hot branding.
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    Determining the Nutritional Status of Mature Beef Cows
    Horsley, Donald Shane (Virginia Tech, 2002-01-09)
    Improved prediction of forage quality and cow performance may enhance the nutritional management of beef cows. In two 12 mo trials, mature beef cows (n=136) grazing tall fescue pastures were used to compare estimates of forage quality and animal performance. Forage quality was estimated by proximate analysis of forage samples (FOR) or by near infrared reflectance spectroscopy of fecal samples (FNIR). Nutritional Balance Analyzer (NutBal), NutBalPro and 1996 NRC Nutrient Requirements of Beef Cattle (NRC) programs were used to predict animal performance. The objectives were to compare FOR and FNIR estimates of CP and TDN and to evaluate the accuracy of cow performance predicted by FNIR-NutBal, FNIR-NutBalPro and FOR-NRC systems. Initial BW, body condition score (BCS), hip height and breed were used to establish cow biotypes for prediction programs. Every 28 d, cow BW and BCS were measured and forage and fecal samples collected. Weather data, cow status and FOR or FNIR results were entered into NutBal, NutBalPro and NRC programs. Forage CP estimated by FNIR (CPFNIR) or FOR (CPFOR) were similar. In trials 1 and 2, correlation coefficients between CPFNIR and CPFOR were r = .24 and r = .43, respectively. Forage TDN estimated by FNIR was greater (P <.05) and lowly or moderately correlated to FOR estimates. Actual BW change between weigh periods (BWCHG) and ADG were similar to NRC predictions, but less (P<.0001) than predicted by NutBal or NutBalPro. The NutBal or NutBalPro mean BCS change between weigh periods (BCSCHG) were greater (P<.001) than NRC or Actual BCSCHG. Actual and NRC BCSCHG were similar (P>.2, trial 1) or tended (P<.1, trial 2) to be similar. Cow performance estimated by NRC was highly correlated to Actual. Absolute differences in animal performance were also investigated for each prediction program. In trials 1 and 2, NutBal and NutBalPro over-predicted BWCHG, ADG and BCSCHG by 40 kg, 1.25 kg/d and .75 BCS, respectively, compared to actual cow performance. It appears that FNIR is a promising predictor of forage CP but not TDN. Also, the FOR-NRC is a satisfactory predictor of cow performance.
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    Effect Of A Cidr Insert And Flunixin Meglumine Administered At The Time Of Embryo Transfer On Pregnancy Rate And Resynchronization Of Estrus In Beef Cattle
    Purcell, Scott Hudson (Virginia Tech, 2004-06-23)
    The objectives of this study were to evaluate the effects of flunixin meglumine (FM), an inhibitor of PGF2a synthesis, administered at the time of embryo transfer (ET) and insertion of an intravaginal progesterone-releasing device (CIDR) at the time of ET on pregnancy rates (PR) and the resynchronization of estrus. Beef cows (n = 796) and heifers (n = 108) at three locations were assigned randomly within age to one of four groups in a 2 x 2 factorial arrangement of treatments with injection of FM (500 mg i.m.; Phoenix Scientific, St. Joseph, MO) 2 to 12 min prior to ET and insertion of a CIDR (1.38 g progesterone; Pfizer, New York, NY) for 13 d immediately following ET as main effects. Fresh or frozen embryos (Stage = 4 or 5; Grade = 1 or 2) were randomly assigned to be transferred to recipients on d 6 to 9 of the estrous cycle. At Location 2 a subset of fresh embryos were split and transferred as fresh half embryos (n = 192). Recipients at Location 2 only (n = 493) were observed for signs of return to estrus beginning 9 d after ET. Recipients that returned to estrus at Location 2 were either bred by AI 12 h after estrus or received an embryo 7 d after estrus. Pregnancy was diagnosed by ultrasonography. Pregnancy rates were analyzed using the LOGISTIC procedure of SAS. Pregnancy rates of split embryo recipients were analyzed separately using the same statistical procedure. Variation in the timing of the return to estrus was determined by an F-test for heterogeneity of variances. Following the initial ET, pregnancy rates of recipients receiving whole embryos were not affected by CIDR administration (P > 0.05; 65% with CIDR, 70% without CIDR), however, there was a significant FM x location interaction on PR (Location 1, 89 vs. 57%; Location 2, 69 vs. 64%; Location 3, 64 vs. 67% for FM vs. no FM, respectively). There was a significant CIDR x FM interaction on PR of recipients receiving split embryos. Pregnancy rates of split embryo recipients receiving CIDR treatment (54%) or FM treatment alone (41%) were less than controls (64%). However, recipients receiving both CIDR and FM had PR similar to controls (60%). The timing of the return to estrus was more synchronous (P < 0.01) for recipients fitted with a CIDR, but PR of recipients bred following a return to estrus did not differ in cows receiving or not receiving a CIDR (P > 0.13; 68 and 62%, respectively). Effects of FM on PR were location dependent and CIDR insertion at ET improved synchrony of the return to estrus.
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    Effect of Timing of Insemination and Synchronization of Estrus Method on Artificial Insemination (AI) Pregnancy Rates in Beef Heifers
    Dorsey, Benjamin Reese (Virginia Tech, 2005-04-25)
    Objectives were to evaluate time of insemination relative to estrus and synchronization with melengestrol acetate (MGA) plus prostaglandin (PG) or progesterone insert (CIDR) plus PG on AI pregnancy rate in beef heifers (n = 662) during Fall or Spring. Fall heifers (n = 349) received MGA-PG (MGA for 14 d followed by PG on d 18) or CIDR-PG (CIDR for 7 d, PG administered 1 d before CIDR removal). Estrus was monitored by HeatWatch® (n = 200) or visually (n = 149). Spring heifers (n = 313) underwent CIDR-PG with detection of estrus by HeatWatch®. Heifers not in estrus by 96-100 h after PG were bred AI as non-responsive AI (NRAI). Across seasons, 548 heifers were bred following estrus (EAI). Heifers synchronized during the Fall with MGA received more (P < 0.05) mounts than Fall CIDR heifers (76.8 ± 6.7 and 47.6 ± 7.4, respectively), but duration of estrus was similar. Fall CIDR heifers had greater (P < 0.05) mounting activity and duration of estrus (47.9 ± 5.2 mounts and 15.5 ± 1.1 h) compared to Spring CIDR heifers (34.5 ± 3.1 mounts and 12.7 ± 0.6 h). Heifers grouped in 4 h blocks from 0 to 24 h had no difference (P > 0.05) in pregnancy rates (mean 62.5 %). Treatment had no effect (P > 0.05) on EAI pregnancy rates. Pregnancy rates across seasons for EAI, NRAI and overall was 61.0 %, 26.3 %, and 54.5%. In conclusion, a 24 h window may exist to successfully AI heifers.
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    The effect of weekly handling on the temperament of peri-puberal crossbred beef heifers
    Matson, Kimberly Monica (Virginia Tech, 2004-05-12)
    The objectives of this study were to determine the effects of handling peri-puberal heifers for 2 h each week on in-chute behavior, isolation behavior, and the time required for each heifer to leave the testing area; and to determine if the location of the facial hair whorl was associated with any of the behavior scores or social dominance order. Crossbred beef heifers (n = 146) were assigned to be walked through, sorted and moved through a chute for 2 hr each wk for 20 wk (HANDLED) or allowed to remain on pasture unless handling was required to treat an injury or disease (CONTROL). In-chute behavior, isolation behavior and exit times were observed and scored at the beginning (0 wk), middle (10 wk) and end of the experiment (20 wk). The facial hair whorl on each heifer was classified as being high (above the eyes), middle (between the eyes), or low (below the eyes). At the end of the experiment pairs of heifers in the HANDLED group competed for a feed source and a social dominance order was estimated. Weekly handling decreased in-chute behavior scores of heifers with facial hair whorl positions classified as medium or low, but not in heifers that exhibited a hair whorl high on their face. Cattle in the HANDLED treatment group which had an initial isolation score of 2 or 3 had the greatest improvement in temperament over the entire experiment when compared to CONTROL animals with the same initial isolation score. The calmest heifers were not negatively affected by the handling, while the most agitated animals in the HANDLED had a similar overall change in isolation score as those animals in the CONTROL group. This indicates that while weekly handling improved the temperament and behavior of heifers with intermediate temperament rating at the outset of the experiment, weekly handling seemed unnecessary for the calmest heifers and did not have a beneficial effect on the heifers rated as the most nervous and agitated at the beginning of the experiment. Social dominance rankings were positively correlated (P < 0.10) with final in-chute behavior scores, but not with the other behavior scores or heifer body weight. Cattle with the hair whorls in the middle of the forehead had higher mean social dominant rank than those with hair whorls higher or lower on the face (P < 0.03). Overall, the results of this experiment indicate that behavior testing can reveal differences in the temperament of heifers and that, other than the most nervous and agitated heifers; repeated handling could serve to improve the temperament of the animals.
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    Effects of Feeding Supplemental Eicosapentanoic Acid and Docosahexanoic Acid to Beef Females on Reproductive Responses and Free Fatty Acids
    Wuenschel, Jeffrey Carl Jr. (Virginia Tech, 2006-08-09)
    The objective of this study was to determine the effects of dietary supplementation of eicosapentanoic (EPA) and docosahexanoic acids (DHA) on reproduction in beef females. In experiment 1, cows (n = 31) were individually fed rumen protected fish meal (FM) or no fish meal (C) supplements. Estrus was synchronized and ovulation induced on d 37. Ovarian follicular growth and diameter were determined by ultrasound on d 35 and d 37. Serum progesterone (P4) profiles were analyzed on d 37 through d 52. On d 52 cows were cannulated, primed with estradiol-17β at -240 min, and stimulated to release PGF2α by oxytocin injection at 0 min with blood sampled every 15 min from -30 min to 240 min. Supplement type did not affect (P > 0.05) follicular diameter, follicular growth or P4 concentrations. In cows fed FM, prostaglandin metabolite (PGFM) concentrations tended (P ≤ 0.10) to be reduced at 0, 30, and 60 min. In experiment 2, crossbred heifers (n = 214) received FM or C concentrates with corn silage from 30 d before estrous synchronization until 14 d after artificial insemination (AI). Serum fatty acid profiles were determined in five heifers from each group . Estrus detection and AI were conducted from d 37 through d 39. Dietary treatment increased (P < 0.05) EPA and DHA concentrations. Dietary treatment did not affect estrus response or AI conception rates and pregnancy rate. Supplementation of FM increased EPA and DHA concentrations but did not affect reproductive factors.
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    Effects of feeding supplemental fat to cows in late gestation on cold tolerance in newborn calves
    Dietz, Richard E. (Virginia Tech, 2000-08-03)
    Two experiments were conducted to investigate the effects of added fat in late gestation cow and heifer diets on thermogenic and neonatal metabolic responses. In Experiment 1, the effects of source of fat in late gestation diets on serum glucose and thermogenic response during short-term cold stress were examined in fall-born neonatal beef calves. Pregnant fall-calving heifers (n = 15) were randomly assigned to three dietary treatments: Control (CON, n=5), Safflower seed (SAF, n=5), or Cottonseed (COT, n=5) supplement. Hay-based isonitrogenous and isocaloric diets met NRC requirements while containing 1.53%, 4.0% and 5.0% fat for CON, SAF and COT diets, respectively. Diets were fed for 47.5 ( 5.4 d before calving. Heifers were weighed weekly and at parturition. At parturition, colostrum samples were taken from the dam, calves weighed, and vigor scores recorded. Calves remained with their dams for 5 h to nurse. At 5.5 h of age, calves were fitted with an indwelling jugular catheter. At 6.5 h of age, calves were placed in a 5°C cold room for 90 min. Shivering scores (1= no shivering, 2 = slight shivering 3 = muscle shivering, 4 = severe muscle shivering), rectal temperatures and blood samples were taken every 15 min. Colostrum samples were analyzed for fat, solids, protein, lactose and IgG concentrations. BW and BCS of heifers at calving, and birth weights and vigor scores of calves were unaffected by diet (P > .5). Mean fat, lactose and IgG concentrations in colostrum were not different (P > .3) among treatments. SAF tended to increase colostral solids (P = .11) and protein (P = .13) compared to COT or CON. During cold stress, calf body temperature increased in a quadratic fashion (P < .03). Mean glucose levels tended (P = .12) to be greater and shivering scores were non-significantly increased in CON compared to SAF or COT calves. Glucose concentrations averaged 74.4, 51.9, and 60.0 ± 7.3 mg/dl, whereas shivering score averaged 2.14, 1.69, and 1.68 ± .24 in CON, SAF and COT calves, respectively. Shivering scores increased in all groups during cold exposure in a linear fashion (P < .001). Vigor scores increased in a linear fashion throughout cold exposure for all groups (P < .04). Cortisol concentrations decreased in a cubic fashion throughout cold exposure for all groups (P < .02). Cortisol concentrations averaged 28.62, 37.7, and 35.65 ± 3.58 ng/ml in CON, SAF and COT calves, respectively. We conclude that calves from dams fed high fat diets containing safflower seeds or cottonseed respond similarly to cold stress, but these responses are not necessarily consistent with greater cold resistance. In Experiment two, pregnant spring-calving cows (n = 75) were randomly assigned to two dietary treatments: Control (CON, n=35) and Cottonseed (COT, n=40). Hay-based isonitrogenous and isocaloric diets met NRC requirements while containing 2.0% and 5.0% fat for CON and COT diets, respectively. Diets were fed for 60 ± 5 d before calving. At parturition, calves were weighed, ambient temperature was recorded and dystocia score was recorded. At 30 min of age, rectal temperature one was recorded and shivering scores (1= no shivering, 2 = slight shivering 3 = muscle shivering, 4 = severe muscle shivering) were recorded. At 180 min postpartum, two blood samples were drawn from each calf to determine blood glucose and cortisol concentrations. At 36 ± 4 h postpartum, two blood samples were again drawn from each calf to determine blood glucose and IgG concentrations. Calf birth weight, calf sex, vigor score, shivering score, time to stand, dystocia score, and serum IgG concentrations were unaffected (P > .5) by diet. Shivering score was affected by ambient temperature (P < .003) and time of calving (P < .006). Calf birth weights were unaffected by diet, calf sex, and the diet x calf sex interaction (P > .2). Mean time to nurse was non-significantly longer (101.2 vs 70.1 min), respectively, for COT calves compared to CON calves. At 30 min (P < .05) rectal temperatures were higher in male than female calves from dams on the COT diet (39.3 vs 39.1°C). Whereas rectal temperatures were lower in male calves than female calves from dams on the CON diet (39.1 vs 39.3°C; diet x calf/sex, P < .05). The same relationship among rectal temperatures was observed at 180 min (diet x calf/sex, P < .05). Changes in body temperature between 30 and 180 min were affected by diet (P < .05) as body temperatures for COT calves increased more from 30 min to 180 min than CON calves. Body temperature at 30 min was affected by time of calving (P < .01). Body temperature at 180 min was affected by ambient temperature at calving (P < .03) and there was a tendency for body temperature at 180 min to be affected by time of calving (P < .09). Serum glucose concentrations at time 180 min were unaffected by diet (P > .3). Serum glucose concentrations at time 36 ± 4 h tended to be affected by sex (P < .07). With glucose levels higher in females (127 mg/dl) than in males (119 mg/dl). Differences in serum glucose at time 180 min and 36 + 4 h were not affected by diet, sex, or diet x sex interaction (P > .7). Serum glucose at 36 ± 4 h was affected by ambient temperature at calving (P < .04). Mean serum cortisol concentrations tended to be higher (47.4 ng/ml vs 36.5 ng/ml) for COT calves compared to CON calves (P < .09). Differences in serum cortisol levels were unaffected by sex or diet x sex interaction (P > .5). When ambient temperature or time of calving were included as covariates, calf weight, calf vigor and serum IgG were unaffected by ambient temperature or time of calving (P > .05).
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    The effects of resynchronization of estrus using the 5 d CO-Synch + CIDR system in beef heifers
    Liles, Amanda Gail (Virginia Tech, 2008-08-05)
    Recent efforts have improved synchronization systems that facilitate timed insemination in beef cattle. However, synchronization systems utilizing a single fixed-time artificial insemination (FTAI) frequently result in 25-40% non-pregnant heifers. The purpose of this study was to determine the effectiveness and define economic parameters of a FTAI resynchronization protocol in beef heifers after synchronization using a 5d CO-Synch + CIDR system. Estrus was synchronized in crossbred heifers (n=176) using 5 d CO-Synch + CIDR with FTAI at 72 h. After the initial AI, open heifers received either resynchronization (RS) or natural service (NS) return service treatments. The RS treatment was diagnosed for pregnancy 29 d after the initial AI, and all open heifers were resynchronized using the 5 d CO-Synch + CIDR with FTAI at 72 h. Heifers diagnosed pregnant following initial AI received no further treatment. Heifers in the NS treatment were exposed to fertile bulls from d 14 to d 66 following initial AI. Return to estrus data were collected using the Heat Watch Estrus Alert System. Total AI pregnancies tended to be higher (P=0.07) for RS (69.7%) than NS (56.5%) heifers. Overall pregnancy rate was greater for NS (89.4%) than for RS (69.7%) at the end of the breeding season (P < 0.01). The cost of RS was $128.63 and for NS was $82.50 per pregnancy. The expected average calf value per heifer exposed was $195.84 for RS treatment and $357.62 for NS treatment. This difference was attributed to the increased number of open heifers in the RS treatment. The resynchronization of estrus after the initial FTAI yielded a limited number of pregnancies in the breeding season in this study. However, the resynchronization program also cost more per pregnancy. Further investigation into resynchronization should focus on both biological and economic impacts.
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    Efficacy of Synthetic Gonadotropin Releasing Hormone Analogs for Control of Ovulation During Estrus Synchronization Protocols
    Cline, Mark A. (Virginia Tech, 2002-01-30)
    Two experiments were conducted to determine efficacy of GnRH analogs, Cystorelin (CYS, gonadorelin diacetate tytrahydrate) and Factrel (FAC, gonadorelin hydrochloride), for use in beef timed AI synchronization. In Experiment one 342 beef cows from 7 herds were assigned CYS or FAC treatment as part of the Ovsynch protocol (GnRH d 0 and 9, Lutalyse d 7). Cattle treated with FAC had greater tendency (P=.09) to be pregnant at d 45. One individual herd demonstrated FAC-treated cows had more pregnancies at day 45. In Experiment two, 18 beef cows received either CYS or FAC as part of the Ovsynch protocol, intensive blood samples, from time -30 to 525 min post GnRH, were collected at each GnRH injection. Ultrasounds were conducted daily over the course of the protocol. A treatment by phase interaction (P=.03) was found for the time to maximum LH concentration, where CYS-treated follicular cows had a shorter interval than did FAC treated follicular or luteal cows. The duration of detectable LH response showed a treatment by phase interaction (P = .02) where follicular and luteal CYS-treated cows had shorter interval than follicular or luteal FAC-treated cows. The variables maximum LH concentration, and area under LH curve did not differ. Cows treated with CYS had more (P=.02) non-dominant follicles. In Experiment three, 16 ewes randomly received either CYS, FAT or Fertagyl (FER; gonadorelin diacetaate tytrahydrate), and FAT's induced LH maximum concentration occurred sooner (P=.02) than CYS. We conclude that either product may be used in beef cows without compromising fertility.
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    Estrus Synchronization for Heifers
    Hall, John B.; Liles, Amanda Gail; Whittier, W. Dee (Virginia Cooperative Extension, 2005-09-01)
    By using estrus synchronization and artificial insemination, you can increase the number of heifers calving early in the calving season, reduce dystocia, use superior sires, and increase calf weaning weights.
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    GnRH Based Estrus Synchronization Systems for Beef Cows
    Hall, John B.; Whittier, W. Dee; Myers, Jim; Cline, Mark A.; Cuddy, David (Virginia Cooperative Extension, 2005-09-01)
    New systems of synchronizing estrus in cows for artificial insemination have been developed using Gonadotropin Releasing Hormone (GnRH). These systems allow producers to artificially inseminate cows with little or no heat detection
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    Induced Cervical Dilation in Sheep: Evaluation of the Effects on Fertilization Rates and Embryonic Development
    Hensley, Erika L. (Virginia Tech, 1999-07-12)
    Experiments were conducted to determine the effects of a treatment used to dilate the cervix for transcervical AI and embryo transfer on pregnancy or fertilization rates in sheep. Experiment 1 was conducted as a 2 × 2 factorial, with the main effects of estradiol-17β (E2) and oxytocin (OT). On d 6 of pregnancy, ewes received (i.v.) 100 μg of estradiol-17β, or saline; 10 h later, ewes received (i.v.) 400 USP units (20 mL) or saline. Blood samples were collected for progesterone analysis. Transrectal ultrasonography was used to determine pregnancy on d 25. Treatment did not affect (χ² , P > .05) pregnancy rates. For nonpregnant ewes, the period × E2 × OT interaction (P < .01) was significant. Experiments were conducted to evaluate the effects of oxytocin and(or) cervical manipulation on fertilization rates. In Exp. 2, nulliparous ewes were assigned to one of two randomized treatment groups: 1) saline or 2) oxytocin. In Exp. 3, multiparous ewes were assigned to one of two randomized treatment groups: 1) saline-cervical manipulation or 2) oxytocin-cervical manipulation. Ewes in Exp. 2 and 3 were laparoscopically inseminated. In Exp. 2 and 3, ewes received (i.v.) either 400 USP units of oxytocin or 20 mL of saline. In Exp. 2 and 3, oocytes and(or) embryos were collected. Treatment did not affect recovery, fertilization, or pregnancy rates in Exp.2 and 3. In conclusion, the treatment used to dilate the cervix in ewes to facilitate the transcervical AI or ET does not seem to affect fertilization or pregnancy rates.
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    Making the Most of Tall Fescue in Virginia
    Smith, S. Ray; Hall, John B.; Johnson, Glenn D.; Peterson, Paul R. (Virginia Cooperative Extension, 2009)
    Tall fescue is a cool-season perennial that is well adapted to Virginia's soils and climate. It is the predominant forage species on over one million acres of hay and pastureland in Virginia.
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    Nutrition and feeding of the cow-calf herd : digestive system of the cow
    Hall, John B.; Silver, Susan (Graduate teaching assistant) (Virginia Cooperative Extension, 2001)
    Cow-calf producers need to understand basic digestive physiology, types of nutrients, and requirements of the cow to become competent on-farm nutritionists.
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    Nutrition and feeding of the cow-calf herd : essential nutrients, feed classification and nutrient content of feeds
    Hall, John B.; Seay, William W.; Baker, Scott M. (Virginia Cooperative Extension, 2001)
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    Nutrition and feeding of the cow-calf herd : production cycle nutrition and nutrient requirements of cows, pregnant heifers and bulls
    Hall, John B.; Seay, William W.; Baker, Scott M. (Virginia Cooperative Extension, 2001)
    Provides an overview of the nutrient requirements during the beef cow production cycle and provides tables to assist in calculating requirements.