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Proceedings, Western Section, American Society of Animal Science Vol. 60, 2009 EFFECT OF TARGETED USE OF A CONTROLLED INTERNAL DRUG RELEASING DEVICE (CIDR) IN AN ESTROUS SYNCHRONIZATION SYSTEM FOR POSTPARTUM BEEF COWS J. B. Hall*, A. Ahmadzadeh, R. H. Stokes, J. K. Ahola, C. Stephenson, J. J. England, and J. B. Glaze, Jr. University of Idaho, Moscow, ID ABSTRACT: The objective of this experiment was to determine if BCS, age, and days postpartum could be used as criteria for inclusion of a CIDR in an estrous synchronization program. Crossbred postpartum beef cows (n = 216) were blocked by age and days postpartum and randomly assigned to CO-Synch+CIDR (CO) or modified CO-Synch+CIDR (Target) synchronization system. The CO-Synch+CIDR system consisted of an injection of GnRH (Cystorelin ® , 100μg i.m.) and insertion of a controlled internal drug releasing device (Eazi-Breed CIDR ® , 1.38 g progesterone) on d 0. On d 7, CIDRs were removed and cows were given PGF2α (Lutalyse ® , 25mg i.m.). Cows were bred by fixed-time AI (FTAI) at 60 to 66 h after CIDR removal with GnRH at AI. Cows assigned to the Target system received the same synchronization protocol as CO cows except: 1) cows in BCS ≥ 5, > 3 yr of age, and > 50 d postpartum did not receive a CIDR (n = 53), 2) detection of estrus occurred from CIDR removal until FTAI, 3) cows detected in estrus before FTAI were inseminated 12 h after observed estrus. All cows were fitted with Estrotect estrus detection aids. Pregnancy rates to AI were similar (P > 0.50) for CO (60.7%; 65/107) and Target (52.3%; 57/109) cows. There was a tendency (P = 0.09) for more cows to be in estrus before FTAI in the CO compared to Target system (62.6% vs. 50.5%, respectively). For cows detected in estrus, AI pregnancy rates were similar (P > 0.50) among systems averaging 63.1%. In contrast, for cows not detected in estrus, more CO cows (P < 0.05) were pregnant to AI compared to Target cows (60.0% vs. 38.8%, respectively). Strategic use of CIDRs in the Target system reduced synchronization costs by $4.74 per cow. Also, estimated returns per 100 cows favored the Target system by $338. We conclude that targeted use of CIDRs can reduce cost of estrous synchronization without compromising AI pregnancy rate. However, overall return with the Target system should be considered. Key Words: Postpartum cows, synchronization, cost. Introduction The use of estrous synchronization and AI in commercial herds can improve calf marketability and cow productivity. Research trials or case studies reported enhancements in calf weaning weight, the percentage of cows calving in the first 21 days, and returns to cow as a result of estrous synchronization and/AI (Sutphin, 2007). Despite these benefits of estrous synchronization and AI, less than 8% of the US beef cow herds use estrous synchronization or AI (NAHMS, 2009). The principal reasons producers give for not using estrous synchronization or AI are labor and/or time (39.1% and 37.7%, respectively) and cost (16.8% and 21.1%, respectively; NAHMS, 2009). Labor and time needed for estrous synchronization and AI is reduced by using systems that eliminate estrus detection and inseminate cows at a fixed-time (FTAI). The incorporation of a controlled internal drug releasing device (CIDR) into estrous synchronization greatly improved synchrony of estrus and pregnancy rates to FTAI (Chenault et al., 2003; Larson et al., 2006) In addition to the increased synchrony, the primary advantage of incorporation of a CIDR in an estrous synchronization protocol is increased estrus response and pregnancy rates in acyclic females (Chenault et al., 2003) The percentage of postpartum cows cycling before the beginning of the breeding season is affected by age of cow, days postpartum, and body condition score (Short et al., 1990). In a herd, a greater percentage of mature cows (≥ 4 yr) cycle before the breeding season compared with 2 and 3 yr old cows. The percentage of cows cycling before the breeding season increases with increasing d postpartum (Short et al., 1990). Cyclicity is enhanced in postpartum cows with BCS ≥ 5 (1 = emaciated to 9 = obese) compared with cows with BCS < 5 (Richards et al., 1986). Therefore, mature cows in good body condition that calve early in the calving season should be cycling at the beginning of the breeding season. Many experiments compare the efficacy of estrous synchronization protocols on pregnancy rates to AI; however, few studies compare the relative cost of different protocols (Johnson and Jones, 2005, 2008) as well as their economic impact on cow and calf productivity. Incorporation of economic and calf performance data with reproductive data may increase producer adoption of estrous synchronization systems. We hypothesized that estrous synchronization costs could be reduced by not using CIDRs in potentially cyclic cows, and that pregnancy rates and/or estimated returns to cow would not be affected by targeted use of CIDRs. The objectives of this experiment were 1) to determine if BCS, age, and d postpartum could be used as criteria for inclusion of a CIDR in an estrous synchronization program, and 2) estimate the economic impact of targeted usage of a CIDR for estrous synchronization and AI. Materials and Methods Two hundred and sixteen crossbred postpartum beef cows were blocked by age and d postpartum and
andomly assigned to CO-Synch+CIDR (CO) or modified CO-Synch+CIDR (Target) synchronization system (Figure 1). The CO-Synch+CIDR system consisted of an injection of GnRH (Cystorelin ® , 100μg i.m., Merial, Duluth, GA) and insertion of a controlled internal drug releasing device (Eazi-Breed CIDR ® , 1.38 g progesterone, Pfizer, New York, NY) on d 0. On d 7, CIDRs were removed and cows were given PGF2α (Lutalyse ® , 25mg i.m., Pfizer). All CO cows were bred by fixed-time AI (FTAI) at 60 to 66 h after CIDR removal with GnRH at AI. Cows assigned to the Target system received the same synchronization protocol as CO cows except: 1) cows in BCS ≥ 5, > 3 yr of age, and > 50 d postpartum did not receive a CIDR (n = 53), 2) detection of estrus occurred from CIDR removal until FTAI, 3) cows detected in estrus before FTAI were inseminated 12 h after observed estrus. Any Target cow not detected in estrus was bred by FTAI at 60 to 66 h after CIDR removal with GnRH at AI. Cows were inseminated by a single AI technician to 1 of 7 bulls. Bulls were pre-assigned to balance bulls over treatment, cow age, d postpartum, and FTAI d. To ensure cows could be inseminated in a timely manner, half of the cows in each treatment began synchronization treatments 24 h before the remaining cows. Therefore, a maximum of 108 cows could be inseminated at FTAI. Cows were assigned to insemination d to ensure d postpartum, cow age, and bull were not confounded with FTAI d. Estrus detection was conducted three times daily at 0800, 1300, and 1800 h from injection of PGF 2α until the morning of FTAI. To facilitate estrus detection, all cows were fitted with Estrotect® (Estrotect, Inc., Spring Valley, WI) estrus detection aids. Day and time of observed estrus was recorded on all treatments. However, only cows on the Target treatment were inseminated 12h after observed estrus. CO-Synch + CIDR or Target Synch (Cows with CIDR) GnRH PG CIDR ® .. 60-66 hr .. 0 7 Treatment Day Target Synch (Cows without CIDR) GnRH PG .. 60-66 hr .. 0 7 Check Heat Treatment Day GnRH AI 9 GnRH Figure 1. Estrous synchronization protocols for cows receiving CO-Synch+CIDR or Target treatments. Estrus was detected on all cows. Cows on the Target protocol that were observed in estrus were bred AI at 12 h after estrus. At 60 to 66 h after PGF2α, Target cows not observed in estrus and all cows receiving CO-Synch+CIDR were bred by fixed-time AI (FTAI) with GnRH. GnRH = 100µg gonadorelin HCl; PG = 25mg PGF2α (dinoprost); CIDR = 1.38g P4 internal drug releasing device. AI 9 Clean-up bulls were introduced 14 d after FTAI, and remained with cows for 45 d. Pregnancy diagnosis was performed via ultrasound on d 55 after FTAI, and final pregnancy diagnosis was via palpation at 90 d after FTAI. Economic calculations were based on cost and returns per 100 cows with the assumption of a 96% overall pregnancy rate and a 93% weaning rate. Distribution of calves into AI, first natural service and second natural service was based on results from the current project. Prices used for cost of estrous synchronization materials were based on local prices. Cost per dose of CIDR, PGF 2α , and GnRH were $8.50, $2.50, and $4.25, respectively. The Target treatment had an extra charge of $150 for additional labor. Calf value was based on the prices obtained from calves sold from the University of Idaho NMCREEC in the fall of 2008. Average price for all calves was $113.00/45 kg for a 250 kg calf with a $6.00/45 kg slide. Average weight of calves was set at 267.6 kg, 244.9 kg, and 226.8 kg for AI, first natural service, and second natural service calves, respectively. The percentage of cows in estrus before FTAI, pregnancy rate to AI, AI pregnancy rate of cows in estrus before FTAI, AI pregnancy rate of cows not observed in estrus, and overall pregnancy rate were analyzed by Chi Square. Economic data were not subjected to statistical analyses as the data were calculated from group means rather than individual calf performance. Results Originally 221 cows were used in the project. Five cows were removed from the project for reasons not related to the experiment (i.e. footrot, injury, temperament). The remaining 216 cows were distributed to CO (n = 107) or Target (n = 109) treatment. Target and CO cows were similar (P > 0.50) in age (avg. 4.9 ± 0.3 yr), d postpartum (avg. 66.4 ± 1.3d), and BCS (avg. 5.8 ± 0.1). The percentage of cows receiving a CIDR was 100% and 51.4 % for CO and Target cows, respectively. More cows tended to be detected (P < 0.09) in estrus before FTAI in the CO (62.6%) compared with the Target system (50.5%). However, pregnancy rate to AI was similar (P > 0.5) among treatments (Figure 2). There was an interaction between synchronization treatment and observed estrus on pregnancy rate to AI. Pregnancy rates were similar (P > 0.50) for cows that exhibited estrus regardless of treatment. However, of cows that did not exhibit estrus, FTAI pregnancy rate was lower (P < 0.05) in Target vs. CO cows (Figure 3). Within the Target group, there was no difference (P > 0.24) in pregnancy rates for cows receiving a CIDR compared with cows not receiving a CIDR (50.0 vs. 54.7%, respectively). Similarly, there was no effect of a CIDR regardless of estrus response in the Target group. Strategic use of CIDRs in the Target system reduced synchronization costs by $4.74 per cow (Table 1). Estimated gross calf sales per 100 cows were $140 more for the CO vs. Target system (Table 2). However, estimated returns per 100 cows favored the Target system by $338 over the CO system due to reduced synchronization costs (Table 3).
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PROCEEDINGS Volume 60 American Soci
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Associations of Prolactin Receptor
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Analysis of Estrone Sulphate, Testo
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Duration of Daily Bull Exposure on
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Effects of Time of Transporting Pri
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Academic Quadrathlon D.C. Rule (Uni
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4. Strategic Plan. The A&C committe
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California, Davis are participating
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WSASAS Symposium Budget: (based on
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Proceedings, Western Section, Ameri
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costs) as “free money” or “pr
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Relative expression Relative expre
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Results and Discussion Calves were
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0.10). Mixed model analyses of thes
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to be 0.11 and 0.14 in the two herd
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efficiency have significant implica
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pilot study that warrants more inve
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steer left the squeeze chute and a
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Gregory, M. E., C. T. Blunn, and M.
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et al. (1990) estimated heritabilit
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Effective population size (N e ), d
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Literature Cited Aho, A. V., B. W.
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Table 3. Estimates of genetic param
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261.98±20.24, 268.30±9.57, 298.50
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Table 1. Least squares means for bi
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DNA, then DNA was washed with EtOH
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Table 1. Least squares means and st
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(Table 1). Cows were combined into
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Rhoades, R. D., J. E. Sawyer, K. Y.
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pregnancy rate was determined via t
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Table 1. Effect of heifer developme
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determined via transrectal ultrason
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Table 1. Effect of winter system on
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increased HCW of steers born earlie
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Proceeding, Western Section, Americ
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degrees of freedom method was used
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Table 2. Supplement × physiologica
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to water and a loose macro- and mic
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Table 2. Effects of calving body co
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ased on average quality and availab
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1 See figure legends for descriptio
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the most important criterions in ra
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Results Perceptions of profitabilit
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input cost into the system. Sand an
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Physiological state has also been h
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Table 3 Percent crude protein (CP),
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conducted for 90 d from Dec 1, 2007
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In f o Proceedings, Western Section
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identified in the commercially avai
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The absence of shade in pen decreas
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T e m Figure 2. Impact of three pre
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weaning date can have a positive im
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Table 1. Systems Backgrounding Perf
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Results and Discussion Maximum and
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Figure 2. Oxygen levels of two comp
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contemporary groups where two intac
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Sund, J. M. and M. J. Wright. 1956.
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thiamin), or 4) HIGH (150 mg·hd -1
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Literature Cited Buckner, C. D., T.
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Serum estradiol concentrations were
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Literature Cited AOAC. 1999. Offici
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Results The BFTH contained four and
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The genetic correlation between MS
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Acknowledgements Red Angus Associat
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absorbed from the small intestine (
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ather than May (P < 0.10). Differen
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May July Low Mod High SE Table 3. R
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Aubrey, TX) to achieve a concentrat
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hormone concentrations in stallions
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* * Figure 3. Mean cortisol concent
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in psyllium-supplemented horses but
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References AOAC. 1990. Official Met
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Implications If available and cost
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Page 195 and 196: Slaughter Characteristic of Ram and
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Page 203 and 204: than animals fed 24% CP-diet during
Page 207 and 208: Over complete 28 days fattening exp
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Page 215 and 216: Todd, A. L., L. M. M. Surber, S. D.
Page 219 and 220: 2006. Effects of supplementing drie
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Page 235 and 236: Table 1. Percentages of heifers tha
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Page 251 and 252: ultrasound examinations of each ova
Page 253 and 254: Fernandez, D. L., J. G. Berardinell
Page 255 and 256: Statistical analysis Data were anal
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Medical Solutions Diagnostics, Los
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LITERATURE CITED Camacho, L. E., J.
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lood vessels occur in a physiologic
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after removal of the P4. This possi
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Results of this experiment indicate
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evaporation). The 2 nd component
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15 ng / mL de Progesterone 12 9 6 3
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collections were performed and tota
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Table 2. Effects of corn condensed
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characteristics of the maize grain
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Proceedings, Western Sections, Amer
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lovegrass straw supplemented with d
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Table 1. Dietary treatments Alfalfa
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dairy cows experienced a post-partu
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etention time and the extent of DMD
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Acknowledgement: Research supported
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BW was affected by supplementation
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(NOAA, 2007, 2008; data not shown).
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particles in the diet (Leonardi and
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indicative of larger villi that wou
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treatment, day, and all possible in
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Table 1. Ingredient composition of
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dried distiller’s grains (DDGS; D
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cattle tend to cost 39% more (Ferna
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and those where WDGS and DDGS were
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of preconditioning. This outcome is
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period prior to harvest. Although L
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Plain, R. 2006. Feeding distiller
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were maintained on a single, dorman
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Table 1. Botanical composition of d
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Leu, L-Val, L-Met, L-His, L-Lys, L-
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Table 2. Effects of abomasal Trp in
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Table 1. Experimental supplements c
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Chen, P. S, T. Y. Toribara and H. W
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stimulate ad libitum intake and ort
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concentrate on the nutritive value
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Results and Discussion Dry matter i
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Crouse J.D., J. R. Busboom, R. A. F
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Table 2. Performance of weaned calv
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important role in enteric methane p
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Figure 1. Dynamics of rumen oxidati
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Table 1. Diet composition Item DM b
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120 +LPS -LPS 10.0 8.0 +LPS -LPS To
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(EE), respectively. Sunflower oil (
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Table 4: Fatty acid concentrations
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Kennely, J.J. 1996. The fatty acid
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Davis, K. C., 248 Davis, N. E., 372
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Orosco, G., 409 Ortega, J., 414, 42
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