Browsing by Author "Wood, Cynthia M."

Now showing 1 - 13 of 13
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    An assessment of the effects of dietary folic acid supplementation on serum folates status, conceptus development and reproductive performance in gilts and sows
    Harper, Allen F. (Virginia Tech, 1992-04-05)
    The effects of dietary folic acid supplementation on serum folate status, conceptus development and reproductive performance in gilts and sows was investigated in a series of experiments. The specific objectives of the study were to: 1) to study the serum folates profile following rapid consumption of a single meal containing different levels of supplemental folic acid; 2) to study the effects of maternal folic acid supplementation on conceptus survival, growth and development prior to mid-gestation in gilts and sows; and 3) to study the effects of multiple levels of dietary folic acid supplementation on sow reproductive performance over four successive parities. In the first experiment (Chapter III), gilts fed a single, rapidly consumed meal, had a rapid increase in serum folates concentration during the first hour postprandial. Within eight hours after feeding, serum folates in the gilts had returned to near prefeeding levels. The results also suggest that supplementing the diet with increasing levels of folic acid over a range of 0 to 4 ppm results in more rapid postprandial uptake and elimination of folic acid from general circulation. In the second experiment (Chapter IV), supplementing the diet of first parity and third parity breeding sows with 2 ppm folic acid had no effect on litter size at day 45 of gestation. However, several measurements associated with placental and fetal growth were increased with folic acid supplementation. Results of a fifth parity trial with four levels of supplemental folic acid were variable and inconclusive. The implications of increased placental and fetal growth up to day 45 of gestation in the first and third parity sows is discussed. In the third experiment (Chapter V), a decline in serum folate concentration in pregnant sows from mating to mid- to late gestation was clearly demonstrated. Supplementing the sow's diet with folic acid over a range of 0 to 4 ppm resulted in a linear increase in serum folate concentration at mating, during gestation and at weaning. However, under the conditions of this experiment, folic acid supplementation had no significant effect on sow reproductive performance.
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    Developing methods to improve welfare in periparturient dairy cows and pre-weaned calves
    Swartz, Turner Harrison (Virginia Tech, 2018-06-06)
    Animal behavior can be used to detect disease and well-being in dairy cattle. In this dissertation, we evaluated the accuracy of an accelerometer to measure step activity, lying time, and lying bouts in pre-weaned dairy calves. The output from the accelerometer was correlated with behavioral measurements taken from video footage. The accelerometer proved to be accurate in identifying step activity (r = 0.99), lying time (r = 0.99), and lying bouts (r = 0.99). The accelerometer was then used to detect behavioral changes occurring around respiratory disease events in pre-weaned calves. Activity declined 1 d prior to clinical disease onset, and this decline persisted for 3 d post-diagnosis. Furthermore, lying bouts declined beginning 2 d prior to diagnosis, and this effect persisted after diagnosis as well. However, aside from a slight reduction in milk intake, feeding behavior was not different between diseased and healthy calves. These data suggest that activity and lying behaviors may be a better measure than feeding behaviors for detection of respiratory disease in pre-weaned dairy calves. Dystocia has detrimental effects on both periparturient dairy cows and newborn calves. We administered a non-steroidal anti-inflammatory drug, meloxicam to periparturient dairy cattle. Treatments included administration prior to calving (MEL-PRE, n = 60), post-calving (MEL-POST, n = 69), or a negative control (CTL, n = 65). We measured the length of labor to determine which cows had easy or difficult calvings. Eutocic MEL-PRE animals produced 6.8 kg/d more milk than eutocic CTL. Regardless of calving difficulty, MEL-PRE animals produced more milk fat, protein, and lactose (kg/d) than the CTL. Additional research is needed to determine appropriate treatments for dystocic calvings. Calves born during the above trial were monitored to determine if meloxicam administration prior to calving impacted newborn calf health and behavior. Calves born difficultly displayed fewer lying bouts for the first few days after birth when compared to calves born easily. No effect of treatment or calving difficulty was noted on calf health. Additional research examining intervention strategies aimed at improving well-being of calves born difficultly is needed.
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    The Effect of Exercise on Lactating Sow Performance
    Higgins, Erinn E. (Virginia Tech, 2011-06-23)
    The objective of this study was to determine the effect of light, daily exercise on body condition score (BCS), soundness (SS), injury (IS), lesions (LS) weaning wt (WW), and back fat (BF) of lactating sows housed in farrowing crates. A total of 24 sows were used in four trials. Body weight (BW), BF, BCS, SS, IS, and LS were recorded at placement into the farrowing barn and again at weaning. A scale of 1 (poor) to 5 (excellent) was used for BCS, SS, and IS. Prior to farrowing, sows were grouped by BW and parity, and assigned to control (no exercise) or experimental (exercise) groups. After farrowing, the exercise sows (n=3) were removed from their crates for 1h/d for 17-19 d and encouraged to exercise; the control sows (n=3) remained in crates 24h/d. Saliva samples were collected 30 min prior to exercise and at 30 and 60 min after exercise for cortisol analysis. Piglets were weaned between 18 and 26 days of age. No difference was found between treatments for sow WW, BCS, IS, average daily feed intake, weaning litter wt, day 7 wt/d of age or piglet survivability. Exercise sows were leaner, sounder, and had more lesions at weaning than control sows (P<0.05). Exercise sows also had higher levels of salivary cortisol on average than control sows (P<0.05). These results indicate that increased movement of sows during lactation led to a decrease in back fat and an increase in soundness, with no affect on piglets.
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    The effect of feeding varying levels of Bifidobacterium globsum a on the performance, scouring index, gastrointestinal measurements and immunity of weanling and growing-finishing pigs
    Agar, Gary A. (Virginia Tech, 1991-08-14)
    Four trials using 312 weanling pigs (average initial wt of 7.2 kg) were conducted to examine the effectiveness of Bifidobacterium globsum a (BGA) on the growth performance, scour scores, humoral and cell-mediated immune response and pH and chloride ion concentration (CIC) of feces and gastrointestinal section contents. The effect of continuous feeding of BGA from weaning to market weight on performance and carcass characteristics was evaluated using pigs from Trial 3 (n=80). Dietary treatments were 0, 5.0 x 104 , 6.7 x 106 and 7.5 x 108 colony forming units (CFU)/d in Trial 1 and 0, 6.0 x 104 , 5.0 x 105 and 5.0 x 106 CFU/d in Trials 2 through 4 and the grower-finisher trial. In Trial 1, ADG was effected quadratically at wk 1-2 and 1-5 (P < .05) and wk 3-5 (P < .01) with pigs fed the medium (6.7 x 106 ) BGA level having higher ADG than control pigs. Quadratic diet effects were also observed for average daily feed intake (ADFI) at wk 1-2, 1-5 (P < .10) and 3-5 (P < .05) with pigs fed the medium level of BGA having greater ADFI than control.
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    The Effects of Genotype, Chromium Picolinate Supplementation, Sex, and Their Interactions on Growth Performance, Carcass Characteristics, and Muscle Quality in Pigs
    Green, Brent Kenneth II (Virginia Tech, 1997-08-22)
    Two trials (n = 160) were conducted to evaluate the effects of the halothane gene, chromium picolinate supplementation, and sex on growth performance, carcass characteristics, and meat quality in pigs. Halothane negative (NN) and halothane carrier (Nn) pigs (barrows, gilts) were supplemented with either 0 or 200 ppb chromium picolinate from 28.7 to 107.3 kg. There were no differences between genotypes for ADG or G/F. Chromium had no significant effect on any growth, carcass, or muscle quality characteristics, although chromium-fed pigs were slightly fatter. Barrows gained faster (P < .001) and consumed more feed (P < .001) than gilts, yielding heavier (P < .001) carcasses, and heavier (P < .05) wholesale cuts. Gilts had less backfat (P < .001) and larger (P < .01) LMA, and tended to gain more efficiently than barrows. Carrier pigs had lower pH values, higher CIE L* values, higher drip loss, and lower protein solubility (P < .05), all indicators of decreased quality. Chromium supplementation resulted in pork with higher (P<.05) CIE a*, CIE b*, and Chroma C values. Halothane carrier barrows and all gilts that were not fed chromium had lower lipid muscle content than NN barrows (P < .05). Gilts had higher CIE L* and a* values (P < .001), less lipid, and higher moisture percentage (P < .02) than barrows. Chromium picolinate did not negatively affect pork muscle quality.
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    Effects of nursery floor space allowance on growth, physiology, and immunology of replacement gilts
    Callahan, Stuart Russell (Virginia Tech, 2013-10-16)
    In U.S. swine herds, sow removal rates due to death and voluntary and involuntary culling exceed 50% annually. This loss poses an economic problem for producers because the cost of acquiring replacement females is great. Although research has shown that crowding in the nursery has negative impacts on growth, research describing effects of crowding on subsequent reproductive performance and longevity in sows is lacking. This experiment was conducted to determine the impacts of crowding during the nursery phase of production on growth, physiology, and immunology in replacement gilts. Gilts (22.3 ± 3.2 d of age and 5.6 ± 0.6 kg BW) were subjected to floor space allocations of 0.15, 0.19, or 0.27 m2/pig during a 7-wk nursery period. Floor space allocations were achieved by altering the number of pigs per pen (14, 11, and 8 gilts/pen, respectively). As was expected, reduced floor space allowance in the nursery negatively affected growth performance although there was inconclusive physiological and immunological evidence to suggest that pigs were experiencing highly stressful conditions. Although feed intake was not measured, changes in blood counts and blood chemistry for gilts allowed reduced floor space were similar to other studies that reported negative effects of crowding on feed consumption. Further study of the gilts involved in this study will aim to determine if there are any links between the effects of crowding during the nursery and subsequent reproductive performance and longevity in the breeding herd.
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    Evaluation of a copper lysine complex and copper sulfate in weanling and finishing pigs, and the effect of copper supplementation on circulating growth hormone and IGF-1 levels
    Apgar, Gary Allen (Virginia Tech, 1994-12-12)
    The objectives of this research were 1) to evaluate CuS0₄ and a CU lysine complex (CuLys) as growth promotants for weanling pigs, 2) to assess the effects of feeding growth stimulating levels of Cu from both sources on dry matter digestibility (DMO) and mineral balance of finishing pigs, and 3) to examine the effect of feeding elevated CU on serum growth hormone and IGF-1 levels. Two trials (176 pigs) were conducted in which pigs were fed 0, 100, 150, or 200 mg/kg Cu from CUS0₄ or CuLys. Elevated Cu increased daily gain and feed intake linearly, with no difference between the sources. Dietary CU linearly increased liver, kidney (P < .001), and brain (P < .05) Cu stores. In the liver, the linear response between the sources was different (P < .001); pigs fed 200 mg/kg Cu from CuLys had the highest CU concentration. Serum CU increased linearly with no difference between the two sources. Serum mitogenic activity increased linearly during wk 1 to 2 and 1 to 5 (P < .05), with no difference between the two sources. Twenty-four barrows were used to examine the effect of Cu additions from both Cu sources on digestibility and mineral balance. Pigs fed Cu from CuLys tended to have greater DMD when compared with controls (P < .10), but percentage of Cu absorbed was not different among the treatments. Pigs fed Cu from both sources absorbed more eu than controls (P < .01), with no difference between sources. Pigs fed CuS0₄ (P < .027) and CuLys (P < .101) absorbed more Fe than controls but Zn balance was not affected. Twelve pigs were cannulated after 7 wk of growth to quantify the effect of elevated dietary Cu on circulating growth hormone and IGF-1 levels. Growth performance was not improved by added Cu, but efficiency of gain was greater for pigs fed Cu when compared with controls (P < .101). Baseline growth hormone secretion was greater in pigs fed Cu (P < .06) for three of four days; however, average concentrations were not affected by diet. Concentrations of IGF-1 were higher in control pigs (P < .05).
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    Influence of treating corn stover and sorghum forage with different nitrogen sources on nutritive value for ruminants
    Ali, Iftikhar (Virginia Tech, 1991-05-06)
    Experiments were conducted to determine: 1) the fermentation characteristics and in vitro dry matter digestibility (IVDMD) of corn (Zea mays) stover treated with different sources of N; 2) digestibility, N utilization and palatabi1ity in sheep fed corn stover treated with different N sources; and 3) fermentation characteristics and nutrient utilization by sheep of sorghum (Sorghum bicolor L., Moench) forage treated with urea an poultry litter. In a small silo study, corn stover was ensiled untreated or after treatment with 3% aqueous NH₃, 50% and 75% poultry litter, 5.8% urea alone or with 10% cattle waste, 1.5% urease powder or 5% soybeans (Glycine max), DM basis. All treatments resulted in substantial increases (P < .01) in CP of corn stover. Lactic acid was detected in substantial levels only in the stover which was untreated and treated with 50% poultry litter. Ammonia and urea treatments decreased NDF content of stover by 4 to 7 percentage units. Increases (P < .01) of IVDMD of 9 to 14 percentage units resulted from treatment with NH₃ or urea. Use of urease sources did not enhance IVDMD.
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    Investigating the effect of dexamethasone on productivity, immune function, and behavior in dystocic periparturient dairy cattle
    Bryant, Dana Marie (Virginia Tech, 2022-01-20)
    Dairy cows are increasingly predisposed to diseases in the periparturient time period due in part to immunosuppression. Dystocia amplifies the disease risk due to the increased tissue trauma and stress the animal endures during the lengthened parturition. To decrease the increased inflammatory response seen in dystocic animals and improve their well-being in the postpartum period, we administered either a potent steroid, dexamethasone (DEX), or a saline control (CON) to cows within 12 hours after a dystocic parturition. The inflammatory marker haptoglobin was measured as well as behavioral and production measures. We observed that primiparous DEX cows exhibited a greater haptoglobin concentration on d 3 and d 7 postpartum compared to primiparous CON cows. Behavior was seen to be altered between the treatments, with DEX cows having reduced locomotion and increased lying times in the week following parturition. These measures could indicate pain reduction, suggesting improved comfort. Milk yield was affected, with a reduction of 7.3 kg/d in multiparous DEX cows in comparison to CON cows for almost the entirety of the first month following dexamethasone treatment. No treatment effects were seen for milk production of primiparous cows. Additional research is needed for further investigation of the immunological and production effects of steroids on postpartum dairy cows, especially between parities.
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    Livestock Update. February 2011
    Greiner, Scott P.; McCann, Mark A.; Whittier, W. Dee; Stanley, Thomas; Wood, Cynthia M.; Kyle, Ashley (Virginia Cooperative Extension, 2011-01-27)
    Contains articles on February beef management, spring calving, preventing scours, bull selection benchmarks, upcoming beef webinar, southwest bull test, expansion decisions for part-time sheep producers, and a tentative schedule for the youth swine education day.
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    Synchronization of estrus, conception rate, and embryonic mortality in beef cattle following treatment with progesterone-releasing intravaginal devices or melengestrol acetate in conjunction with PGF₂α
    Hall, Stacey J. (Virginia Tech, 1991-07-05)
    The objective of these experiments was to determine the effects of and/or interactions among estrous synchronization treatments, reproductive status, and stage of the estrous cycle on estrous response (ER), first service conception rates (CR), pregnancy rates (PR), and embryonic mortality (EM) after 25 d of gestation. Angus or Angus crossbred cattle (n=391) at two locations were assigned to receive either melengestrol acetate for 7 d (MGA-PGF; .5 mg/hd/d, n=136) or progesterone releasing intravaginal device for 7 d (PRID-PGF; n=139) or to serve as untreated controls (n=116). All animals in MGA and PRID treated groups coincidentally received 25 mg prostaglandin F₂α (PGF) on the final day of treatment. Real time, B-mode, ultrasound with a 7.5 mHz linear-array transducer was used to conduct three ovarian scans at 7-d intervals beginning 7 d prior to initiation of treatment. Jugular blood samples were collected at each scanning period. Serum was harvested and stored at 4°C until radioimmunoassayed for progesterone (P4). Serum P4 levels in conjunction with ovarian scans were used to determine cycling status and stage of the estrous cycle at initiation of treatment. Cattle treated with PRID-PGF exhibited a greater synchronized ER (P < .06) than MGA-treated cattle. Cycling animals had a greater ER than noncycling animals, regardless of treatment (P < .01). Anestrous postpartum cows and prepubertal heifers treated with PRID-PGF exhibited a greater ER (P < .05) within 7 d than either MGA-treated or untreated control animals. Conception rates of cattle treated with PRID-PGF beginning late (> Day 16) in the estrous cycle were improved over those of MGA-treated cattle (P < .13) at the same stage. Pregnancy rate at 21 d was higher in PRID-treated cattle than untreated controls (P < .01). Ultrasound scans for embryonic viability were conducted at 25, 45, and 65 d of gestation. Calving data was collected to characterize EM between 65 d and term. The majority of embryonic loss occurring after 25 d of pregnancy occurred before 45 d. Synchronization treatment had no effect on the extent of EM occurring after 25 d of gestation. Embryonic mortality occurring between d 45 and 65 (2%) and between d 65 and term (3%) when combined were similar in magnitude to EM occurring between 25 and 45 d of gestation (4.8%). In conclusion, PRID for 7 d combined with PGF was a superior synchronization treatment for the mixed group of cyclic and anestrous cattle.
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    Use of Triptorelin Acetate for Inducing Ovulation and Facilitating Fixed Time Artificial Insemination of Sows Weaned on Small-Scale and Niche Market Pig Farms
    Fabi, Amanda Jean (Virginia Tech, 2017-04-11)
    Developing a single fixed-time artificial insemination (FTAI) protocol would benefit small-scale and niche market pork producers by decreasing semen costs and labor associated with detection of estrus. The objective of this study was to test the efficacy of an artificial insemination (AI) breeding system using triptorelin acetate, a GnRH agonist (OvuGel®; JBS United Animal Health, LLC, Sheridan, IN) that induces ovulation. A total of 96 sows (parity, 3.5 ± 0.2; body condition score (BCS), 2.5 ± 0.07) were weaned (h 0) after a 24.8 ± 0.6 d lactation on five participating small swine farms and allocated to one of four treatment groups: 1) TRT1: (n = 24) OvuGel applied intravaginally at h 96 and AI at h 120; 2) TRT2: (n = 24) P.G. 600® (400 IU eCG and 200 IU hCG, Merck Animal Health, Inc., De Sota, KS) injected intramuscularly at weaning, OvuGel at h 96 and AI at h 120; 3) TRT3: (n = 24) P.G. 600 at weaning, and AI at 0 and 24 h after first detection of estrus; and 4) TRT4: (n = 24) AI at 0 and 24 h after first detection of estrus. Treatments 1 and 2 were FTAI protocols with sows being inseminated without regard to estrus onset. Treatments 3 and 4 were consistent with current industry AI practices. The proportion of females displaying estrus by d 7 post-weaning was greater (P < 0.05) for sows that received OvuGel (94.5 %) compared to sows that did not receive OvuGel (82.2 %). There were no effects (P > 0.05) of P.G. 600 or P.G. 600 x OvuGel on females displaying estrus by d 7 or d 10 post-weaning. Weaning to estrus interval was decreased (P < 0.05) for sows that received P.G. 600 (4.9 ± 0.4 d) compared to sows that did not receive P.G. 600 (5.4 ± 0.4 d). There were no effects (P > 0.05) of OvuGel or P.G. 600 x OvuGel on the weaning-to-estrus interval. There were no effects of P.G. 600, OvuGel or P.G. 600 x OvuGel (P > 0.1) on pregnancy rate (total sows pregnant/inseminated) (61.2 %), total litter size (11.3), number born dead (1.0) or number of mummies (0.2). There was an effect (P < 0.05) of P.G. 600 x OvuGel on total born live (10.2). Sows treated with OvuGel had a greater number of live piglets born per semen dose (5.4) compared to sows that did not receive OvuGel (3.2) (P < 0.05). These results suggest that FTAI protocols may be employed on small-scale pig farms without compromising reproductive performance.
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    Using Commercially Available Hormones to Enhance Swine Reproductive Efficiency in Batch Management Systems
    Petrone, Rosalie Catherine (Virginia Tech, 2015-07-23)
    The U.S. hog industry's shift to vertically-integrated, intensively-managed operations brought about a variety of management systems for breeding herds, including batch farrowing. In this system, groups of sows are weaned in 2- to 5- week intervals, making estrus synchronization of new gilts and sows critical to maintaining reproductive efficiency in the herd. The use of commercially available hormones to synchronize estrus in this system has not been extensively studied. This experiment was conducted to determine whether the use of commercially available hormones (MATRIX® and P.G. 600®; Merck Animal Health, De Sota, KS) in a 5-week batch management system had a positive impact on reproductive efficiency in gilts and sows over the course of 3 parities. Gilts were allocated to an Entry Group (A, B, or D) and then assigned to a treatment, Hormone-Assisted (HA) (5 mL P.G. 600 injection 5 days and/or fed 15 mg/day of MATRIX for 14 consecutive days prior to the breeding week) or Control (no exogenous hormones). Gilts and sows were checked daily for estrus with a mature boar, and a group was bred using AI during a 7-day breeding period every 5 weeks and allowed to farrow up to 3 parities. Among groups, there was a tendency (P = 0.08) for more HA than control gilts to display estrus and be mated on schedule. For gilts within Group A, more (P < 0.01) HA than control females displayed estrus and were mated. Body weight at first service for gilts in Groups A and B were higher than Group D (P < 0.01). Overall, there was no effect of treatment on (P = 0.20) non-productive days. There was a strong tendency for HA sows to have a greater (P = 0.07) number of parities completed than control sows; Total pigs born (P < 0.05) and total pigs born alive (P < 0.05) were greater for HA sows than control sows. In Parity 1, Group D sows had a lesser number of pigs born (P < 0.01) and pigs born alive (P < 0.02) than Groups A and B; The number of pigs weaned differed between entry groups (P < 0.05) (Group B > Group A > Group D); Control sows weaned more pigs (P < 0.02) and had a greater litter weaning weight (P < 0.01) than HA sows; HA sows had a lower (P < 0.05) wean-to-estrus interval than control sows. No significant effects of group or treatment were observed in Parities 2 and 3. The use of exogenous hormones to synchronize estrus had a positive impact on reproductive efficiency in HA gilts/sows in a 5-week batch management system.