Housing system and herd size interactions in Norwegian dairy herds; associations with performance and disease incidence

Background

According to the Norwegian animal welfare regulations, it has been forbidden to build new tie-stall barns since the end of 2004. Previous studies have shown that cow performance and health differ between housing systems. The interaction between housing system and herd size with respect to performance and disease incidence has not been evaluated.

Methods

Cow performance and health in 620 herds housed in free-stall barns were compared with in 192 herds housed in tie-stall barns based on a mail survey and data from the Norwegian Dairy Herd Recording and Cattle Health Systems. The housing systems herds were comparable with respect to herd size (15-55 cows). Associations between performance/disease incidence and housing system, herd size and year of building the cow barn were tested in general linear models, and values for fixed herd size of 20 and 50 cows were calculated. On the individual cow level mixed models were run to test the effect of among others housing system and herd size on test-day milk yield, and to evaluate lactation curves in different parities. All cows were of the Norwegian Red Breed.

Results

Average milk production per cow-year was 134 kg lower in free-stall herd than in tie-stall herds, but in the range 27-45 cows there was no significant difference in yields between the herd categories. In herds with less than 27 cows there were increasingly lower yields in free-stalls, particularly in first parity, whereas the yields were increasingly higher in free-stalls with more than 45 cows.In free-stalls fertility was better, calving interval shorter, and the incidence rate of teat injuries, ketosis, indigestions, anoestrus and cystic ovaries was lower than in tie-stalls. All of these factors were more favourable in estimated 50-cow herds as compared to 20-cow herds. In the larger herd category, bulk milk somatic cell counts were higher, and the incidence rate of mastitis (all cases) and all diseases was lower.

Conclusion

This study has shown that there is an interaction between housing system and herd size, and that performance and health is not universally better in small free-stalls than in tie-stalls.     

Bovine respiratory syncytial virus seroprevalence and risk factors in endemic dairy cattle herds

The herd seroprevalence of bovine respiratory syncytial virus (BRSV) was studied in 59 dairy cattle herds using serology on random selected animals stratified by two age classes (heifers, cows). Risk factors for primary infections in heifers were investigated using a questionnaire on management conditions and data on bovine viral diarrhoea (BVD) status. At least one seropositive cow was present in all the herds. In 25% of the herds all individual were seropositive and 22% of herds had all heifers seronegative. Analysis of the influence of risk factors retained summer pasture and BVD status. In particular, absence of summer pasture and the BVD positive status of heifers were associated with an increased risk of BRSV infection in heifers group.     

Retrospective comparison of three locoregional techniques for pelvic limb surgery in dogs

ObjectiveTo retrospectively compare the efficacy and duration of effect of three commonly used locoregional blocks in dogs undergoing pelvic limb orthopaedic surgery.Study designRetrospective clinical study.AnimalsA total of 236 dogs that underwent pelvic limb surgery and were administered a locoregional technique.MethodsA total of 236 hospital records were reviewed and 230 included in statistical analysis. Dogs were grouped as following: electrostimulation-guided pre-iliac femoral and sciatic nerve block (group PFS, n = 70); ultrasound-guided saphenous and sciatic nerve block (group SS, n = 76); or lumbosacral epidural (group EPI, n = 84). In group EPI, bupivacaine 0.5% or ropivacaine 0.75% was used with morphine. Dogs were pain scored (short form of the Glasgow Composite Measure Pain Scale) hourly following recovery from anaesthesia. Analysed data included: time to first postoperative dose of methadone, pain score at that time, intraoperative rescue analgesia, intraoperative hypotension and ability to walk and urinate overnight. Separate analyses were performed including all pelvic limb surgeries and including only elective stifle surgeries. Kruskal–Wallis and Mann–Whitney tests were performed. A p value < 0.05 was considered significant. The median (range) is reported.ResultsFor all pelvic limb surgeries, the time to first postoperative methadone was 530 (110–1337), 440 (140–1030) and 466 (135–1094) minutes in groups EPI, PFS and SS, respectively, and was not significantly different. Postoperatively, 10/84, 15/70 and 12/76 dogs in groups EPI, PFS and SS, respectively, did not require methadone (nonsignificant). Significantly fewer dogs in group EPI (18%) required intraoperative rescue analgesia compared with group SS (38%), but not compared with PFS (30%). Significantly more dogs in group EPI had hypotension intraoperatively (30%) and urinary retention postoperatively (62%).Conclusions and clinical relevanceIntraoperative analgesia may be superior with EPI than SS for some surgeries of the pelvic limb, but not for stifle surgeries. All three techniques provided similar requirement for postoperative analgesia, but EPI caused higher incidence of intraoperative hypotension and postopertive urinary retention.     

Subsoil improvement in a tropical coarse textured soil: Effect of deep-ripping and slotting

In many coarse textured soils, limited root development and biomass production are attributed to adverse physical conditions in the subsoil. The current study was undertaken on an Arenic Acrisol located in Northeast Thailand (i) to assess whether subsoil physical characteristics influence crop rooting depth, and (ii) to compare the benefits associated with conventional tillage with that of localised subsoil loosening on crop performance and selected soil attributes. Control plots consisted of disk ploughing; the implemented treatments were conventional deep-ripping and localised slotting below the planting line. A crop rotation consisting of a legume followed by maize was established annually to assess the impact of these treatments on crop performance. In the control treatment, root development was restricted to the topsoil (0–20 cm) due to high subsoil bulk density (>1.6 Mg m⁻³). After deep-ripping, no improvement was observed in bulk density, rooting depth and in crop performance. The implementation of a slotting treatment systematically improved root development in the slotted subsoil, root impact frequency increasing from <0.2 to 0.6–0.8 (P = 0.01) despite no change in the bulk densities of the subsoil. This systematic improvement in root development could be explained by (i) reduced slumping that enable root development prior to recompaction and/or (ii) preferential drainage in the slot and therefore decreased resistance to root penetration. In a dry year maize yield was improved by 78% (P = 0.01); the deep-rooting legume Stylosanthes was tested only a wet year and its biomass production increased by >40% (P = 0.03). This study highlights the detrimental impact of subsoil compaction on root development and the potential role of slotting in coarse textured soils as a long-term management tool in addressing adverse subsoil physical characteristics that limit deep-rooting.     

Cloud-radiative forcing and climate: results from the Earth radiation budget experiment

The study of climate and climate change is hindered by a lack of information on the effect of clouds on the radiation balance of the earth, referred to as the cloud-radiative forcing. Quantitative estimates of the global distributions of cloud-radiative forcing have been obtained from the spaceborne Earth Radiation Budget Experiment (ERBE) launched in 1984. For the April 1985 period, the global shortwave cloud forcing [-44.5 watts per square meter (W/m(2))] due to the enhancement of planetary albedo, exceeded in magnitude the longwave cloud forcing (31.3 W/m(2)) resulting from the greenhouse effect of clouds. Thus, clouds had a net cooling effect on the earth. This cooling effect is large over the mid-and high-latitude oceans, with values reaching -100 W/m(2). The monthly averaged longwave cloud forcing reached maximum values of 50 to 100 W/m(2) over the convectively disturbed regions of the tropics. However, this heating effect is nearly canceled by a correspondingly large negative shortwave cloud forcing, which indicates the delicately balanced state of the tropics. The size of the observed net cloud forcing is about four times as large as the expected value of radiative forcing from a doubling of CO(2). The shortwave and longwave components of cloud forcing are about ten times as large as those for a CO(2) doubling. Hence, small changes in the cloud-radiative forcing fields can play a significant role as a climate feedback mechanism. For example, during past glaciations a migration toward the equator of the field of strong, negative cloud-radiative forcing, in response to a similar migration of cooler waters, could have significantly amplified oceanic cooling and continental glaciation.     

Liquid chromatography/mass spectrometry and liquid chromatography/nuclear magnetic resonance as complementary analytical techniques for unambiguous identification of polymethoxylated flavones in residues from molecular distillation of orange peel oils (Citrus sinensis)

Liquid chromatography/mass spectrometry and liquid chromatography/nuclear magnetic resonance techniques with ultraviolet/diode array detection were used as complementary analytical tools for the reliable identification of polymethoxylated flavones in residues from molecular distillation of cold-pressed peel oils of Citrus sinensis. After development of a liquid chromatographic separation procedure, the presence of several polymethoxy flavones such as sinensetin, nobiletin, tangeretin, quercetogetin, heptamethoxyflavone, and other derivatives was unambiguously confirmed. In addition, proceranone, an acetylated tetranortriterpenoid with limonoid structure, was identified for the first time in citrus.     

Evaluation of an iscom ELISA used for detection of antibodies to Neospora caninum in bulk milk

The intracellular parasite Neospora caninum is increasingly recognized as an important cause of abortion and stillbirth in cattle. Presence of specific antibodies indicates infection, and the immunostimulating complex (iscom) enzyme-linked immunoassay (ELISA) has previously been evaluated for use on individual milk and sera. In the present study, this test is investigated for use on bulk milk. In this study, 124 herds were used to analyse the relationship between within-herd prevalences based on individual sera and bulk milk optical densities. The individual test results were translated into a herd-level result, which enabled comparison of the bulk milk test result to the aggregate of individual serum results. The relative contribution of milk from cows with different milk yield and antibody status to the tank, i.e. its composition, was expected to influence the outcome of the bulk milk test. Therefore, sensitivity and specificity were calculated at different cut-off levels, not only using a standard cross-tabulation technique, but also a logistic regression model. By using the latter method, the sensitivity and specificity could be estimated adjusting for milk yield covariates. Specificity was estimated to be high ( approximately 98%) at the 0.20 cut-off, which can be used as a decision threshold to rule in infection. With more equal emphasis on sensitivity and specificity, a lower cut-off should be used. Although infection cannot be completely ruled out, herds with test results below 0.05 are highly likely to be non-infected. The within-herd prevalence of false negative herds is probably less than 10-15% at this level. From what is known about test performance at the individual level and the prevalence of infection, the estimate of the specificity of the bulk milk test should be quite accurate while the sensitivity is likely to be underestimated. We confirmed that the performance of the bulk milk test depends on the milk tank composition. In particular the milk yield of cows with high antibody levels affects the probability of a positive outcome of the bulk milk test.     

两种普鲁兰类酵母菌株Aureobasidium pullulans对三种核果类褐腐病菌Monilinia laxa,Monilinia fructicola和Monilinia fructigena的生物控制作用

本试验研究了从"Redhaven"桃果肉中分离得到的两种拮抗酵母菌株L1和L8对三种核果类褐腐病原菌(Monilinia laxa,Monilinia fructicola及Monilinia fructigena)的离体和活体拮抗效果。这两种拮抗菌株是经初步验证能够减轻桃和油桃的褐腐病症状后筛选出的,并最终通过分子生物学及形态学手段鉴定为Aureobasidium pullulans(出芽短梗霉菌)。通过活体接种三种褐腐病菌的试验研究发现,两种拮抗菌的高压灭菌悬液及无菌过滤液对果实褐腐病的发生均无抑制作用,而含有L1和L8菌株的菌悬液可完全抑制M.laxa和M.fructicola引起的褐腐病的发生,并使M.fructigena引起的褐腐病发病率分别降低70%和90%。在另一项试验中,将油桃用两种拮抗菌液处理后接种三种褐腐病菌,然后将其在0℃下贮藏21 d,再在20℃下放置7 d。结果表明,低温抑制了褐腐病的发生,处理和对照果实均无褐腐病的症状。但在20℃下放置7 d后,对照果实的褐腐病发病率均超过了45%,而LI和L8处理分别可以将接种M.fructigena病原菌果实褐腐病的发病率降低89.8%和91.2%,说明两种拮抗菌的处理可完全抑制接种M.laxa和M.fructicola引起的果实褐腐病的发生。两种拮抗酵母菌株的最佳抑菌浓度为108CFU.mL-1,L1在107CFU.mL-1浓度时也具有较好的抑菌效果。L8菌株在107CFU.mL-1浓度时对由M.fructigena和M.fructicola引起的果实褐腐病无抑制活性,处理与对照果实无差异。而对于接种了M.laxa的油桃果实,与对照相比,107CFU.mL-1浓度的L8菌株却可显著降低褐腐病的发病率。尽管在0℃和20℃下贮藏的油桃果实伤口处的L1和L8菌的数量增长较慢,但已经足够控制果实褐腐病的发生。综上所述,本项研究确定了可作为开发采后生物杀菌剂活性成分的两种A.pullulans拮抗菌株,并用于抑制引起核果类作物采后严重经济损失的三种Monilinia真菌。