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RC Handcock N Lopez-Villalobos LR McNaughton PJ Back GR Edwards RE Hickson 《New Zealand veterinary journal》2020,68(5):272-282
ABSTRACT Aims: To examine the relationship between liveweight (LWT) at 12 months as a proportion of LWT at 21 months of age (LWT(12/21)%) and first lactation and cumulative 3-year milk production in dairy heifers in New Zealand. Methods: Liveweight and milk production records were obtained for dairy heifers born from June to December (spring-calving season) between 2006–2007 and 2013–2014 dairy seasons; production records included first lactation (n?=?140,113) and cumulative 3-year (n?=?67,833) milksolids and energy-corrected milk (ECM) yields. Heifers were classified into five breed groups; Holstein-Friesian, Holstein-Friesian crossbred, Jersey, Jersey crossbred and Holstein-Friesian-Jersey crossbred. Within each breed group heifers were categorised into quintiles based on 21-month LWT. The LWT(12/21)% was calculated for each animal. Relationships between LWT(12/21)% and milk production within each breed group and LWT category were estimated using linear mixed effects models including the linear and quadratic effects of LWT(12/21)%. Results: The relationship between LWT(12/21)% and milk production was predominantly curvilinear, with lower milk production at lesser LWT(12/21)% compared with greater LWT(12/21)%. For all breed groups and most LWT categories, heifers that were 55 or 65% LWT(12/21)% produced greater ECM and milksolids yields compared with heifers that were 45% LWT(12/21)%. Holstein-Friesian, Holstein-Friesian crossbred and Holstein-Friesian-Jersey crossbred heifers that were 65% LWT(12/21)% produced greater cumulative 3-year ECM and milksolids yields compared with heifers of the same breed group that were 45% LWT(12/21)% Conclusions and clinical relevance: Heifers that were a greater proportion of their 21-month LWT at 12 months of age produced more first lactation and cumulative 3-year milk yields than heifers that were a lesser proportion of their 21-month LWT at 12 months of age. These results indicate that increased growth in early life of New Zealand dairy heifers is beneficial to future milk production. 相似文献
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Management Strategies Aiming to Improve Horse Welfare Reduce Embryonic Death Rates in Mares 下载免费PDF全文
E Malschitzky AM Pimentel P Garbade MIM Jobim RM Gregory RC Mattos 《Reproduction in domestic animals》2015,50(4):632-636
The objective of this retrospective study was to evaluate the effect of management strategies aiming to improve animal well‐being on pregnancy and embryonic death (ED) rates. Breeding records of a cohort of 1206 Thoroughbred mares brought to a stallion station facility, to be bred with the stallions housed there, were evaluated during ten breeding seasons. Mares were blocked according to management strategies in two groups: Stress and Relax. Strategies used to improve animal well‐being (Relax group) were as follows: stopping the teasing routine, reducing or eliminating stall confinement, reducing the number of mares per group and maintaining herd stability during the breeding season. In barren mares, the pregnancy rate was higher in the Relax group (91.8%) when compared to the observed in Stress group (84.7%). However, no difference in pregnancy rates were observed (Stress = 85.2% vs. Relax = 86.2) in foaling mares. ED rate was higher in barren and foaling mares of the Stress group mares (25.5% and 26.8%, respectively) compared with the Relax group (16.1% and 14.7%, respectively). No significant differences were observed on foal heat pregnancy rate between groups; yet, the embryo loss on foal heat was significant reduced in Relax mares (Relax = 8.7% vs Stress = 24.5%). In conclusion, management strategies aimed to reduce social stress can reduce early pregnancy losses and the average cycles per pregnancy, improving reproductive performance in mares. 相似文献
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The cross pressure (P) and temperature (T) dependence of the elastic moduli (Cij) of single-crystal samples of periclase (MgO) from acoustic wave travel times was measured with ultrasonic interferometry: partial differential2C11/ partial differentialP partial differentialT = (-1.3 +/- 0.4) x 10(-3) per kelvin; partial differential2C110/ partial differentialP partial differentialT = (1. 7 +/- 0.7) x 10(-3) per kelvin; and partial differential2C44/ partial differentialP partial differentialT = (-0.2 +/- 0.3) x 10(-3) per kelvin. The elastic anisotropy of MgO decreases with increasing pressure at ambient temperature, but then increases as temperature is increased at high pressure. An assumption of zero cross pressure and temperature derivatives for the elastic moduli underestimates the elastic anisotropy and overestimates the acoustic velocities of MgO at the extrapolated high-pressure and high-temperature conditions of Earth's mantle. 相似文献
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Clarisse G Cardoso Danilo RC Marques Thiago HM da Silva Ewaldo de Mattos‐Junior 《Veterinary anaesthesia and analgesia》2014,41(6):636-643
ObjectiveTo evaluate the cardiorespiratory, sedative and antinociceptive effects of dexmedetomidine alone or in combination with methadone, morphine or tramadol in dogs.Study designExperimental, blinded, randomized, crossover study.AnimalsSix mixed breed dogs (two males and four females) weighing 10 ± 4 kg.MethodsThe animals were randomly divided into four treatments: D (10 μg kg?1 of dexmedetomidine), DM (dexmedetomidine 10 μg kg?1 and methadone 0.5 mg kg?1); DMO (dexmedetomidine 10 μg kg?1 and morphine 0.5 mg kg?1), and DT (dexmedetomidine 10 μg kg?1 and tramadol 2 mg kg?1). The combinations were administered intramuscularly in all treatments. The variables evaluated were heart rate (HR), respiratory rate (fR), rectal temperature (RT), systolic arterial pressure (SAP), sedation scale and pedal withdrawal reflex. These variables were measured at T0 (immediately before the administration of the protocol) and every 15 minutes thereafter until T105.ResultsA decrease in HR and fR occurred in all the treatments compared with T0, but no significant difference was observed between the treatments. The RT decreased from T45 onward in all the treatments. The SAP did not show a difference between the treatments, but in the DT treatment, the SAP was lower at T30 and T45 compared with T0. The D treatment had lower scores of sedation at T15 to T75 compared with the other treatments, and the DMO and DM treatments showed higher scores at T60 and T75 compared with DT.Conclusions and clinical relevanceThe treatments with morphine and methadone added to the dexmedetomidine showed higher sedation scores than the control treatment and the treatment with tramadol added to the dexmedetomidine showed no relevant differences in any of the variables evaluated in the study. 相似文献
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Barbara C. Reynolds Jennifer Hamel Jason Isbanioly Leonardo Klausman Kevin K. Moorhead 《Pedobiologia》2007,51(4):273-280
Our study compared decomposition and litter microarthropod abundance among five plant communities in a mountain floodplain/fen complex located in the southern Appalachian Mountains, USA. We found that the least disturbed plant communities, red maple in particular, have the quickest decomposition, the greatest number of litter microarthropods, the highest soil organic carbon, and the lowest soil pH. Positive correlations were shown between soil organic carbon and total microarthropods; negative correlations were found between soil pH and total microarthropods. No correlations were found between soil moisture and decomposition or total microarthropod numbers. We conclude that soil characteristics related to disturbance, rather than to the presence of a closed canopy, are the main influences on decomposition and litter microarthropods. 相似文献