Intramammary infections and risk factors for clinical mastitis in herds with low somatic cell counts in bulk milk

Ten herds with low somatic cell counts in bulk milk had an incidence of clinical mastitis of only 2.2 per 100 cows whereas 10 other herds with similarly low cell counts had an incidence of 53.6 per 100 cows. The major pathogens in the herds with a high incidence were Escherichia coli, Streptococcus uberis, Staphylococcus aureus and the coagulase-negative staphylococci. The percentage of uninfected quarters in the herds with a high incidence of clinical mastitis was 21.4 per cent compared with 12.2 per cent in the herds with a low incidence of clinical mastitis. The prevalence of coagulase-negative staphylococci, Corynebacterium bovis and Micrococcus species was higher in the herds with a low incidence of clinical mastitis. There was a significant linear relationship between the percentage of uninfected quarters and the incidence of clinical mastitis in the herds with a high incidence of clinical mastitis. In herds with a low incidence of clinical mastitis significantly less teat disinfection after milking was practised. The results suggest that infections with minor pathogens tend to protect cows against mastitis, and that teat disinfection after milking may increase the percentage of uninfected quarters and lead to an increased risk of clinical mastitis in herds with low somatic cell counts in bulk milk.     

Use of oxytocin to attain cervical dilation for transcervical embryo transfer in sheep

The aim of this work was to determine whether a cervical dilation protocol (CDP) composed of only oxytocin can be used to perform transcervical (non-surgical) embryo transfer in sheep (NSET) without affecting the viability of the corpus luteum (CL). Likewise, we evaluated whether a cervical transposing test with a Hegar dilator (CT Hegar test), performed at oestrous time, could be used to screen ewes for NSET (greater or lower chances to transpose the cervix). For that, oestrous and ovulation synchronization was performed in 25 Santa Inês ewes to induce the dioestrous condition. Animals went through the following CDP in a crossover design: E + OX, oestradiol benzoate (100 µg intravenously [IV]) and oxytocin (100 IU IV); OX, oxytocin (100 IU IV); and SAL, saline solution (IV). Using a Hegar dilator, cervical transposing attempts were performed at oestrous (D0) and dioestrous time (D8). The viability of the CL (morphology, luteal blood flow and progesterone values) was evaluated by ultrasonography (colour Doppler and B-mode) and by serum progesterone measurement from D7 to D13. The cervical transposing rate was lower for the SAL group (64%; 16/25; p < .05) and did not differ between the E + OX (88%; 22/25, p > .05) and OX (84%; 21/25, p > .05) groups. No treatment affected the CL viability. The CT Hegar test showed a high sensitivity (85.7%–93.3%), satisfactory accuracy (72%–84%), low false-negative rate (6.7%–14.6%), but high false-positive rate (46%–66.7%). In conclusion, a CDP protocol composed exclusively of oxytocin can lead to good cervical transposing rates and does not affect the viability of the CL. In addition, a screening test (CT Hegar) performed at oestrus can identify ewes for which cervical transposing will likely not occur at NSET.     

Initial growth and survival of Eucalyptus spp. and Mimosa caesalpiniifolia Benth. in silvopastoral systems and their impact on herbage accumulation of Urochloa decumbens Stapf R. D. Webster

Agroforestry Systems - Silvopastoral systems (SPS) combine tree, herbaceous, and animal components, and may contribute to improve productivity and diversification of activities over time. This...     

Radiographic and CT features of colonic entrapment due to an omental rent in a dog

A 2‐year‐old female spayed Great Dane presented for inappetence and lethargy. Abdominal radiographs revealed a severely gas‐distended segment of colon. Computed tomography was performed and characterized a 180° anticlockwise colonic torsion with entrapment in a mesenteric/omental rent without vascular compromise. Exploratory laparotomy confirmed entrapment, but not colonic torsion. Computed tomography provided important information to assist clinical management decisions for this dog with colonic entrapment.     

Comparison of Conventional Freezing and Vitrification with Dimethylformamide and Ethylene Glycol for Cryopreservation of Ovine Embryos

The aim of this work was to evaluate the efficiency of the cryoprotectants dimethylformamide and ethylene glycol for cryopreservation of ovine embryos using vitrification and conventional freezing. The recovered embryos were distributed randomly in three treatment groups: Gr. 1: conventional freezing (n = 44), Gr. 2: vitrification with ethylene glycol (n = 39) and Gr. 3: vitrification with dimethylformamide (n = 38). Quality of fresh embryos in control group as well as of frozen and vitrified embryos was examined by three methodologies: staining with propidium iodide and Hoechst 33258 and evaluation under fluorescent microscopy, evaluation of re‐expansion and hatching rates after culture, and determination of apoptotic index with TUNEL technique. It was established that re‐expansion rate in all treatment groups was similar. In the same time, hatching rates were higher in Gr. 1 (40.5%) and Gr. 2 (35.3%) in comparison with Gr. 3 (15.5%, p < 0.05). The number of dead cells in vitrified embryos of Gr. 2 and Gr. 3 was higher (42.6 ± 26.2 and 63.2 ± 34.65, respectively) in comparison with Gr. 1 (conventional freezing, 10.1 ± 8.5, p < 0.05). Embryos vitrified with dimethylformamide included the same quality of apoptotic cells that Gr. 1 (conventional freezing) and fresh embryos. In conclusion, the dimethylformamide and ethylene glycol used as cryoprotectant to vitrify ovine embryos, in the concentrations and exposition time tested in this work, were not as efficient as the conventional freezing for cryopreservation of ovine embryos Thus, the conventional freezing with ethylene glycol was the most efficient method to cryopreserve ovine embryos in comparison with vitrification.     

选择性采食方式对生长猪的日粮选择及其生产性能的影响

为研究当猪能够从3种不同成分的颗粒料中作出采食选择时其是否能采食其所需的最佳日粮,特利用单独圈养的生长猪进行了一次试验。试验选用40头杂交猪(20头阉公猪,20头小母猪),其初始体重为22.0±2.1kg,在4周试验期中分成对照日粮组(C组)和选择性采食日粮组(CF组)。C组试验猪饲喂单一的全价料颗粒料,CF组试验猪能自由地从高能量颗粒料(E)、高蛋白颗粒料(P)和预混料/其它成分颗粒料(P/R)3种不同成分的颗粒料中挑选其所需的日粮。CF组试验猪利用一个分成3个隔间可同时供应3种颗粒料(每个隔间供应一种颗粒料)的长形料槽供料。所有日粮均自由采食。在采取选择性采食的方式中,小母猪所选择的高蛋白颗粒料要多于去势公猪,两者分别为222和193g/kgDM。而C组试验猪(无论小母猪还是去势公猪)均饲喂粗蛋白含量相同的日粮(即204g/kgDM;性别间差异显著P<0.05)。本试验不存在其他处理与性别之间的相互作用。对照组猪的净能摄入量高于试验,分别为13.8和10.3Mj/d(P<0.001)。小母猪的净能摄入量往往低于去势公猪,分别为12.6Mj/d和11.4Mj/d。CF组试验猪预混料/其它成分颗粒料的摄入量非常少(15g/d;13g/kgDM)。CF组仔猪日增重明显低于C组(779g/d和541g/d;P<0.001)。结果显示,当3种颗粒化的日粮配料被分别加入长料槽3个隔间中的其中一个时,仔猪不能选择最适合其生长的一种日粮配料。至于试验仔猪不能选择一种最适合其需要的日粮配料是否是由于特殊的器官感觉(如口味、风味或颗粒的物理性状)所致还有待进一步研究。如果弄清了这一原因,人们就能利用此方法去研究日粮成分(如次级配合料)或不同饲料处理方法的重要性。