Increased yearling weight as a proportion of 21-month weight was associated with increased milk production in dairy heifers     

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   

Evaluation of pathogenicity and aggressiveness of <Emphasis Type="Italic">F. langsethiae</Emphasis> on oat and wheat seedlings relative to known seedling blight pathogens     

Samuel M. Imathiu  Martin C. Hare  Rumiana V. Ray  Matthew Back  Simon G. Edwards 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(2):203-216

Fusarium and Microdochium species are causal agents of seedling blight of small-grain cereal crops where they may contribute to a significant reduction in crop establishment and final yield. Two experiments were carried out to investigate the potential pathogenicity and aggressiveness of F. langsethiae, a recently identified fungus linked with the contamination of cereals with high levels of the trichothecene mycotoxins, HT-2 and T-2. An artificial seed inoculation method involving conidial suspensions was used and the experiments conducted in a growth cabinet set at either 5 or 15°C with a 12 h photoperiod. Known seedling blight pathogens of the genus Fusarium and Microdochium were used for comparison. At 15oC, F. culmorum, M. nivale and M. majus caused seedling blight of oats and wheat with F. culmorum, on average being the most aggressive than the latter two. At 5oC, only F. culmorum and M. nivale caused seedling blight of oats and wheat. Under the experimental conditions employed, F. langsethiae and F. poae failed to produce seedling blight disease indicating that these two species are not pathogenic to oat and wheat cultivars, Gerald and Claire respectively, at the seedling stage of development. They are therefore unlikely to affect crop establishment and other yield components such as tiller number, grain yield per head as well as grain weight if there is no subsequent foot-rot and/or head blight where infected seeds are sown.  相似文献   

Characterisation of midgut digestive proteases from the maize stem borer Busseola fusca     

George D  Ferry N  Back EJ  Gatehouse AM 《Pest management science》2008,64(11):1151-1158

BACKGROUND: Insect damage is a major constraint on maize production. Control of Busseola fusca (Fuller) in sub‐Saharan Africa is relatively ineffective; the major larval digestive enzymes were characterised with a view to developing future control strategies. RESULTS: Using BODIPY‐FL Casein, maximal activity was at pH 9.5, with six protease forms visualised by gelatin‐PAGE. Synthetic substrates and diagnostic inhibitors demonstrated the presence of serine proteases. Chymostatin was a potent inhibitor of general proteolysis (90%), providing strong evidence for the presence of chymotrypsin; it also caused significant inhibition (>95%) with SA₂PFpNA as substrate. The I₅₀ values for chymostatin with casein and SA₂PFpNA were 0.0075 µM and 0.06 µM respectively. Z‐Phe‐Arg‐pNA activity was inhibited by chymostatin and TLCK (50 and 30% respectively), suggesting the presence of trypsin‐like activity. BApNA hydrolysis was also strongly inhibited by chymostatin and TLCK (92 and 75%), suggesting trypsin activity, while SBBI, PMSF, pepstatin and E‐64 had no significant effect. Interestingly, SBBI (I₅₀ = 0.39 µM ) and SBTI both inhibited general proteolysis by approximately 70%, suggesting that SBBI's dual inhibitory role makes this inhibitor a potentially useful candidate for expression in maize for control of B. fusca. CONCLUSION: These results provide a basis for the rational design of insect‐resistant transgenic maize expressing protease inhibitors. Copyright © 2008 Society of Chemical Industry  相似文献   

Resistance pattern and antioxidant enzyme profiles of protoporphyrinogen oxidase (PROTOX) inhibitor-resistant transgenic rice     

Ha Il Jung  Kyoungwhan Back 《Pesticide biochemistry and physiology》2008,91(1):53-65

We quantified the resistance levels of transgenic rice plants, expressing Myxococcus xanthus protoporphyrinogen oxidase (PROTOX) in chloroplasts and mitochondria, to PROTOX inhibitors, acifluorfen, oxyfluorfen, carfentrazone-ethyl, and oxadiazon. We also determined whether active oxygen species-scavenging enzymes are involved in the resistance mechanism of transgenic rice. The transgenic rice line M4 was about >200-fold more resistant to oxyfluorfen than the wild-type (WT). M4 was also resistant to acifluorfen, carfentrazone-ethyl, and oxadiazon, but did not show multiple resistance to imazapyr and paraquat, which have different target sites. Acifluorfen, oxyfluorfen, carfentrazone-ethyl, and oxadiazon reduced the chlorophyll content in leaves of WT, but had minimal or no effect on M4. The PROTOX inhibitors also caused significant lipid peroxidation in the treated leaves of WT rice. However, the malondialdehyde production in M4 was not affected by these herbicides. The WT rice had higher activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase than M4 after treatment with PROTOX inhibitors. A similar response was observed in all cases of antioxidant isozyme profiles analyzed. However, the induction in antioxidant activity in WT was not enough to overcome the toxic effects of a PROTOX inhibitor so the plant eventually died.  相似文献   

Analgesic and anti-hyperalgesic effects of epidural morphine in an equine LPS-induced acute synovitis model     

van Loon JP  Menke ES  L'ami JJ  Jonckheer-Sheehy VS  Back W  René van Weeren P 《Veterinary journal (London, England : 1997)》2012,193(2):464-470

Epidural morphine is widely used in veterinary medicine, but there is no information about the anti-hyperalgesic and anti-inflammatory effects in acute inflammatory joint disease in horses. The analgesic, anti-hyperalgesic and anti-inflammatory effects of epidural morphine (100mg/animal or 0.17±0.02mg/kg) were therefore investigated in horses with acute synovitis. In a cross-over study, synovitis was induced in the talocrural joint by intra-articular lipopolysaccharide (LPS). The effect of epidural morphine was evaluated using physiological, kinematic and behavioural variables. Ranges of motion (ROM) of the metatarsophalangeal and talocrural joints were measured, clinical lameness scores and mechanical nociceptive thresholds (MNTs) were assessed and synovial fluid inflammatory markers were measured. The injection of LPS induced transient synovitis, resulting in clinical lameness, decreased ranges of motion in the talocrural and metatarsophalangeal joints, decreased limb loading at rest and increased composite pain scores. Epidural morphine resulted in a significant improvement in clinical lameness, increased ROM and improved loading of the LPS-injected limb at rest, with no effects on synovial fluid inflammatory markers. Morphine prevented a decrease in MNT and, hence, inhibited the development of hyperalgesia close to the dorsal aspect of inflamed talocrural joints. This study showed that epidural morphine provides analgesic and anti-hyperalgesic effects in horses with acute synovitis, without exerting peripheral anti-inflammatory effects.  相似文献   

Coordinated Expression of Cytosolic and Chloroplastic Glutamine Synthetase During Reproductive Stage and Its Impact in GS1 RNAi Transgenic Rice     

Tieu-Ngoc Nguyen Le  Beomgi Lee  Kyoungwhan Back  Young Soon Kim  Hyeonsook Cheong 《水稻科学》2018,25(5):250-260

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Malignant melanoma of the pelvis as a possible cause of pelvic limb lameness in two gray mares     

de Blaauw JA  Rijkenhuizen AB  van Nieuwstadt RA  Grinwis GC  Back W 《Tijdschrift voor diergeneeskunde》2003,128(17):512-518

Two grey mares, a 12-year-old Arabian and a 13-year-old Lippizaner cross, were referred for chronic pelvic limb lameness and abduction of the limb during the non supporting phase of the stride. The clinical examination revealed melanomas under the tail and on the perineum, and oedema of the proximal lame limb. A mass in the pelvic area was detected on rectal palpation. Laparoscopy was performed and the provisional diagnosis of malignant melanoma was made. Histological examination of the biopsy taken under laparoscopic control from the mass in the pelvis confirmed the diagnosis of malignant melanoma. In the postmortem examination a large black mass in the pelvis and metastases in several organs were diagnosed. The process under the tail showed microscopically the characteristics of dermal melanomatosis. The metastases showed the appearance of a malignant melanoma. The lameness and abduction during the non supporting phase of the stride were possibly caused by a combination of pain, a mechanical limitation, and paresis/paralysis. When an older grey horse with melanomas on the predilection sites is submitted with pelvic limb lameness and abduction of the limb during the non supporting phase of the stride, a malignant melanoma in the pelvis is one of the differential diagnoses and a rectal examination should be performed. Diagnostic laparoscopy in the standing horse can be useful to confirm the provisional diagnosis.  相似文献   

Quantitative electromyographic examination in myogenic disorders of 6 horses     

Wijnberg ID  Franssen H  Jansen GH  Back W  van der Kolk JH 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(2):185-193

Electromyographic needle examination (EMG), including the semiautomatic quantitative analysis of motor unit action potential (MUAP), is an important diagnostic tool for myopathy in humans. The diagnostic possibilities of this technique have not been fully explored in horses; however, recent studies have shown that MUAP analysis can be performed in conscious horses. To determine the diagnostic possibilities of EMG in horses, we compared the EMG results of the subclavian muscle, the triceps, and the lateral vastus muscle in 6 equine patients thought to have myogenic disorders with those in 7 normal control horses. The EMG results were compared with the results of the histopathologic examination of the lateral vastus muscle in patients and controls. Histopathologic examination showed muscle disease in 3 patients. In the patient group, several types of abnormal spontaneous activities were observed (mainly fibrillation potentials and positive sharp waves), and the MUAPs of the patient group had a markedly shorter duration and lower amplitude than those of the control group. In the subclavian muscle, triceps, and lateral vastus muscle of affected horses, the MUAP duration was 5.0 +/- 0.4 (mean +/- SD), 3.9 +/- 0.3, and 4.7 +/- 1.1 milliseconds, respectively. The MUAP amplitude was 217 +/- 55, 150 +/- 74, and 180 +/- 54 microV; the number of phases was 2.4 +/- 0.2, 2.5 +/- 0.3, and 2.3 +/- 0.1; and the number of turns was 2.6 +/- 0.2, 2.4 +/- 0.2, and 2.8 +/- 0.5, respectively. In conclusion, it appears that the EMG may be a more sensitive method than other techniques for examining muscle biopsies for diagnosis of early-stage myopathy in horses.  相似文献   

Relationship of duration of estrus to pregnancy rate in normally cycling, nonlactating mares     

L D Burwash  B W Pickett  J L Voss  D G Back 《Journal of the American Veterinary Medical Association》1974,165(8):714-716

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Development, characterization, and preliminary evaluation of a temperature-sensitive mutant of Ornithobacterium rhinotracheale for potential use as a live vaccine in turkeys     

Lopes VC  Back A  Shin HJ  Halvorson DA  Nagaraja KV 《Avian diseases》2002,46(1):162-168

A temperature-sensitive (Ts) mutant strain of Ornithobacterium rhinotracheale (ORT) was developed after exposure of the wild-type organism to N-methyl-N'-nitro-N-nitrosoguanidine. The Ts mutant strain grew at 31 C but had its growth inhibited at 41 C unlike wild-type parent strain. The Ts mutant and parent strains were characterized. Morphologic and biochemical properties of wild-type and mutant strains did not show any differences. The strains were also characterized by polymerase chain reaction (PCR)-based fingerprinting methods. Results showed similar patterns in repetitive sequences by repetitive PCR (enterobacterial repetitive intergenic consensus, highly conserved repeated DNA elements present in Streptococcus pneumoniae (BOX), repetitive extragenic palindromic, and Salmonella enteritidis repetitive element primers); however, random amplified polymorphic DNA fingerprinting was able to differentiate mutant and parent strains showing a unique pattern for each of the ORT strains. The rationale for the use of a Ts strain as a vaccine is based on the ability of the mutant to colonize the upper respiratory tract but not the lower respiratory tract and systemic system of the birds, where the wild-type strain causes severe lesions. In a preliminary evaluation, Ts strain of ORT was recovered from tracheas and choanae of Ts-treated turkeys for 13 days postadministration of the strain either in drinking water or by oculonasal instillation. Humoral immune response was detected in Ts-vaccinated but not in control group birds after 3 wk postadministration. Results suggest that Ts strain of ORT has promising potential use as a live vaccine for ORT.  相似文献