Comparison of three reproductive management strategies for lactating dairy cows using combination of estrus detection or ovulation synchronization and Fixed-Timed Artificial Insemination

The objective of this study was to compare the reproductive performance of lactating dairy cows submitted to first AI after combination of estrus detection and fixed timed AI (FTAI) and FTAI only. Cows were randomly assigned to receive AI at detected estrus between 50 and 70 d in milk (DIM), if not detected in estrus, were enrolled in either Ovsynch (ED-Ov, n = 485) or PRIDsynch (ED-PR, n = 505) protocols; or received FTAI at 80 DIM after Double-Ovsynch protocol (DO, n = 501). Cows were body condition scored (BCS) at calving and at 43 DIM; and evaluated for postpartum disorders within 7 d postpartum; clinical mastitis, lameness and bovine respiratory disease were recorded until first AI. Ovarian cyclicity was monitored at 43 and 50 DIM, and at 70 and 77 DIM. Pregnancy diagnoses (PD) were performed at 32 and 63 d after AI. Overall prevalence of postpartum anovulation was 7.8%. Pregnancy per AI (P/AI) did not differ between reproductive strategies at 32 d PD (ED-Ov = 43.2%; ED-PR = 41.7%; DO= 45.3%). Primiparous cows had greater P/AI than multiparous cows (53.7% vs 36.8%). Cows on farm 1 had lower P/AI compared with their counterparts on farm 2 (42.1% vs 45.4%). Cows with BCS > 2.5 at 43 DIM had greater P/AI compared with cows with BCS ≤ 2.5 (44.5% vs 34.7%). Similar P/AI for cow's receiving AI at detected estrus and FTAI, low prevalence of disease anovulation may have contributed to the similar performance of ED-Ov, ED-PR and DO.

Association of days in close up, gestation length, and rumination around time of calving with disease and pregnancy outcomes in multiparous dairy cows

The purpose of this study was to evaluate the effect of rumination times and days spent in a close-up group before calving (DCU) on early-lactation health and reproductive outcomes in dairy cows. Data were gathered for 719 cows located in a single herd. Herd management and reproductive records were analyzed for cows receiving treatment in the first 30 d of lactation (days in milk; DIM) for clinical mastitis, reproductive tract disease, ketosis, milk fever, and displaced abomasum. Rumination times for each cow were downloaded daily from the herd's automated collar system used to generate heat and health alerts for each cow beginning at 21 d precalving until 14 d postcalving. During the first 30 DIM, 121 cows (18%) developed at least 1 disease-any combination of ketosis (40 cows, 5.9% of total), mastitis (17 cows, 2.5%), metritis (75 cows, 11%), milk fever (17 cows, 2.5%), or displaced abomasum (28 cows, 4.1%); 305 cows (45%) were pregnant again at 100 DIM, and an additional 139 cows (20%) were pregnant at 150 DIM. Principal component analysis was used to determine the relationship between gestation length and DCU and their association with the odds of developing disease in early lactation. We did not find any significant association between precalving rumination time and disease within the first 30 DIM. Higher rumination time in the week before calving was shown to be strongly linked to a shorter time to subsequent pregnancy, whereas rumination times postcalving were not associated with changes in the time to pregnancy. Principal component analysis showed that a curvilinear combination of gestation length and DCU (principal component 1) was significantly associated with changes in disease incidence in the first 30 DIM. Gestation length and time spent in close up are important management factors in reducing the incidence of disease in early lactation, and rumination times around calving may help predict future reproductive outcomes.

Evaluation of a culture-based pathogen identification kit for bacterial causes of bovine mastitis

Accurate identification of mastitis-causing bacteria supports effective management and can be used to implement selective use of antimicrobials for treatment. The objectives of this study were to compare the results from a culture-based mastitis pathogen detection test kit ('VetoRapid', Vétoquinol) with standard laboratory culture and to evaluate the potential suitability of the test kit to inform a selective treatment programme. Overall 231 quarter milk samples from five UK dairy farms were collected. The sensitivity and specificity of the test kit for the identification of Escherichia coli, Staphylococcus aureus, coagulase-negative staphylococci, Streptococcus uberis and Enterococcus spp. ranged from 17 per cent to 84 per cent and 92 per cent to 98 per cent, respectively. In total, 23 of 68 clinical samples were assigned as meeting the requirement for antimicrobial treatment (Gram-positive organism cultured) according to standard culture results, with the test kit results having sensitivity and specificity of 91 per cent and 78 per cent, respectively. Several occurrences of misidentification are reported, including S. aureus being misidentified as coagulase-negative staphylococci and vice versa. The test kit provides rapid preliminary identification of five common causes of bovine mastitis under UK field conditions and is likely to be suitable for informing selective treatment of clinical mastitis caused by Gram-positive organisms.

Lymphnode metastasis in head and neck squamous cells carcinoma: multivariate analysis of prognostic variables

Cervical lymphnodes metastatization by the squamous cell carcinoma of the head and neck is well known as a prognostic negative factor as far as survival is concerned. Multivariate analysis has been used on 207 cases of head and neck squamous cell carcinomas (HNSCC) in order to identify the possible prognostic significance of a group of clinical and histopathological characteristics, aiming to find a correlation with the possible occurrence of cervical lymphnodes. Two hundred and seven patients (168 males and 39 females, mean age: 62 years) with SCCHN were studied. They underwent surgery alone and radiotherapeutic associated treatment. Variables regarding the patient, carcinoma and histology were analysed: age, sex, smoking and alcohol consumption, performance status, concomitant internal pathologies (cardiopathies, hepatopathies, broncho-pneumopathies, metabolic disorders), site and size of primary tumor (T stage), number and size of laterocervical lymph node localization (clinical N stage), grading, vascular permeation, perineural infiltration. Multivariate analysis of prognostic factors was performed using BMDP's PLR programme. Some variables showed a great risk of lymphnode metastasis; among sites: supraglottic larynx (p = 0.05), base of the tongue (p = 0.04), hypopharynx (p = 0.05); some histological parameters as lower degree of histological differentiation (p = 0.02), the presence of vascular permeation (p = 0.06) and perineural invasion (p = 0.07) appear to represent predisposing factors for the onset of adenopathies. By considering prognostic factors as shown, it is possible to better identify metastasis risk cases, that leads to improved therapeutical strategies.

Hydrogels of poly(ethylene glycol): mechanical characterization and release of a model drug

Thermosensitive polymer networks were synthesized from poly(ethylene glycol), hexamethylene diisocyanate and 1,2,6-hexanetriol in stoichiometric proportions. By varying the amount of 1,2,6-hexanetriol and the molar mass of the poly(ethylene glycol), a wide range of networks with different crosslinking densities was prepared. The networks obtained were characterized by the temperature dependence of their degree of equilibrium swelling in water and by their Young's moduli. For each network, the molecular weight between crosslinks was estimated. The structure of the hydrogels was analysed with respect to scaling laws, and it was found that the results obtained with PEG 1500 and PEG 6000 hydrogels are in agreement with theoretical predictions, whereas those obtained with PEG 400 hydrogels are in disagreement. The release properties of PEG hydrogels were studied by the determination of the diffusion coefficient for acebutolol chlorhydrate and by an analysis of the effect of temperature on these coefficients. Finally, these release properties were correlated with the swelling and structural properties of the hydrogels.