Metabolic and inflammatory responses to the common sweetener stevioside and a glycemic challenge in horses with equine metabolic syndrome.

Extracts derived from the leaves of the stevia plant (stevioside) are commonly used as sweeteners for humans and horses. Stevioside appears to be safe for human consumption, including for individuals with insulin dysregulation. In the horse, the safety or metabolic effects of stevioside on normal animals or on those with metabolic dysfunction are unknown. Furthermore, the inflammatory response to a glycemic challenge or to stevioside in horses is not well defined. Therefore, the objective of this study was to measure the effects of stevioside and a glycemic challenge on insulin, glucose, and inflammatory responses in horses with a common metabolic dysfunction (equine metabolic syndrome or EMS) compared with non-EMS controls. To accomplish this, 15 horses were selected; 8 EMS and 7 age-matched controls. An oral sugar test was performed using Karo corn syrup (karo) or stevioside in a random crossover design. Horses were given 0.15 mL/kg body weight of karo or its equivalent grams of sugar in stevia dissolved in water. Blood samples were collected by jugular venipuncture before administration of either stevia or karo and at 60 and 240 min after administration. Serum was used for glucose and insulin determination and plasma for isolation of peripheral blood mononuclear cells (PBMCs) for inflammatory cytokine analysis via flow cytometry and reverse transcription PCR (RT-PCR). Stevia appeared to stimulate lower glycemic and insulinemic responses when compared to karo, in particular in EMS horses. EMS and control horses had inverse inflammatory responses to administration of either stevia or karo with EMS horses having a proinflammatory response (P ≤ 0.05). These data provide evidence as to why horses with EMS may be predisposed to developing laminitis, potentially as a result of an exaggerated inflammatory response to glycemic and insulinemic responses. Furthermore, the data provide new avenues for exploring mechanisms behind the syndrome, in particular when using a glycemic challenge.

A comparison of timed artificial insemination and automated activity monitoring with hormone intervention in 3 commercial dairy herds.

The objective of this study was to compare the reproductive performance of cows inseminated based on automated activity monitoring with hormone intervention (AAM) to cows from the same herds inseminated using only an intensive timed artificial insemination (TAI) program. Cows (n=523) from 3 commercial dairy herds participated in this study. To be considered eligible for participation, cows must have been classified with a body condition score of at least 2.50, but no more than 3.50, passed a reproductive tract examination, and experienced no incidences of clinical, recorded metabolic diseases in the current lactation. Within each herd, cows were balanced for parity and predicted milk yield, then randomly assigned to 1 of 2 treatments: TAI or AAM. Cows assigned to the TAI group were subjected to an ovulation synchronization protocol consisting of presynchronization, Ovsynch, and Resynch for up to 3 inseminations. Cows assigned to the AAM treatment were fitted with a leg-mounted accelerometer (AfiAct Pedometer Plus, Afimilk, Kibbutz Afikim, Israel) at least 10 d before the end of the herd voluntary waiting period (VWP). Cows in the AAM treatment were inseminated at times indicated by the automated alert system for up to 90 d after the VWP. If an open cow experienced no AAM alert for a 39±7-d period (beginning at the end of the VWP), hormone intervention in the form of a single injection of either PGF2α or GnRH (no TAI) was permitted as directed by the herd veterinarian. Subsequent to hormone intervention, cows were inseminated when alerted in estrus by the AAM system. Pregnancy was diagnosed by ultrasound 33 to 46 d after insemination. Pregnancy loss was determined via a second ultrasound after 60 d pregnant. Timed artificial insemination cows experienced a median 11.0 d shorter time to first service. Automated activity-monitored cows experienced a median 17.5-d shorter service interval. No treatment difference in probability of pregnancy to first AI, probability of pregnancy to repeat AI, pregnancy loss, time to pregnancy, or proportion of pregnant cows at 90 d past the VWP existed. Based on these results, inseminating cows using AAM with hormone intervention can achieve a level of reproductive performance comparable to TAI. Considering the strict cow selection criteria used in this study, interpretation of results for on-farm implementation should be performed cautiously; the results cannot be directly extrapolated to whole herds of cows.

Cervical Vertebral Lesions in Equine Stenotic Myelopathy.

Skeletal lesions in the articular processes of cervical vertebrae C2 to C7 were compared between Thoroughbred horses with cervical stenotic myelopathy (17 males, 2 females; age, 6-50 months) and controls (6 males, 3 females; age, 9-67 months). Lesions identified by magnetic resonance imaging occurred with an increased frequency and severity in diseased horses and were not limited to sites of spinal cord compression. Lesions involved both the articular cartilage and trabecular bone and were further characterized using micro-computed tomography and histopathology. The most common histologic lesions included osteochondrosis, osseous cyst-like structures, fibrous tissue replacement of trabecular bone, retained cartilage matrix spicules, and osteosclerosis. Osseous cyst-like structures were interpreted to be true bone cysts given they were a closed cavity with a cellular lining that separated the cyst from surrounding bone. This is the first report of bone cysts in the cervical articular processes of horses with cervical stenotic myelopathy. The morphology and distribution of the lesions provide additional support for the previously proposed pathogenesis that developmental abnormalities with likely secondary biomechanical influences on the cervical spine contribute to equine cervical stenotic myelopathy.

The relationship between compost bedded pack performance, management, and bacterial counts.

The objective of this study was to assess the relationships among temperature, moisture, carbon-to-nitrogen (C:N) ratio, space per cow, and bacterial counts from bedding material collected from compost bedded pack (CBP) barns. A field survey of 42 routinely aerated CBP barns was conducted in Kentucky between October 2010 and March 2011. Two bedding material samples of 1,064.7 cm(3) each were collected during a single site visit from 9 evenly distributed locations throughout each barn and thoroughly mixed to create a composite sample representative of the entire CBP. Bacterial counts were determined for coliforms, Escherichia coli, streptococci, staphylococci, and Bacillus spp. University of Kentucky Regulatory Services (Lexington) laboratory personnel performed nutrient analyses to determine moisture, carbon, and nitrogen contents. Surface and 10.2-cm pack depth temperatures were collected for each of the 9 evenly distributed locations and the mean calculated to produce a composite temperature. Space per cow was calculated as the total CBP area divided by number of cows housed on the CBP. The GLM procedure of SAS (SAS Institute Inc., Cary, NC) generated models to describe factors affecting bacterial counts. Bacterial counts were 6.3 ± 0.6, 6.0 ± 0.6, 7.2 ± 0.7, 7.9 ± 0.5, and 7.6 ± 0.5 log 10 cfu/g of dry matter for coliform, Escherichia coli, streptococci, staphylococci, and Bacillus spp., respectively. Composite temperature, CBP moisture, C:N ratio, and space per cow had no effect on coliform counts. Escherichia coli reached a peak concentration when the C:N ratio was between 30:1 and 35:1. Staphylococci counts increased as ambient temperature increased. Streptococci counts decreased with increased space per cow and composite temperature and increased with increasing ambient temperature and moisture. Streptococci counts peaked at a C:N ratio ranging from 16:1 to 18:1. Bacillus spp. counts were reduced with increasing moisture, C:N ratio, and ambient temperature. Mastitis-causing bacteria thrive in similar conditions to that of composting bacteria and microbes, making elimination of these at higher temperatures (55 to 65°C) difficult in an active composting environment. Producers must use recommended milking procedures and other preventative practices to maintain low somatic cell count in herds with a CBP barn.

Effect of a tea tree oil and organic acid footbath solution on digital dermatitis in dairy cows.

Copper sulfate is the industry gold standard footbath ingredient for controlling dairy cow digital dermatitis. However, when used footbath solutions are deposited on soil, high levels of copper in the soil may result, which can have toxic and negative effects on plant growth. An alternative to copper sulfate is Provita Hoofsure Endurance (Provita Eurotech Ltd., Omagh, UK), which is a biodegradable solution containing organic acids, tea tree oil, and wetting agents. The objective of this study was to quantify changes in digital dermatitis frequency when using Provita Hoofsure Endurance and copper sulfate in a split footbath in 3 commercial dairy herds. This study was conducted from January 5, 2012, to March 19, 2012, in 3 commercial Kentucky dairies with 120, 170, and 200 milking Holstein cows. None of the herds was using a footbath for digital dermatitis control before the study. Footbath solutions were delivered using a split footbath. During the study, a 3% Hoofsure Endurance solution for the left hooves and a 5% copper sulfate solution for the right hooves was used. Digital dermatitis was scored every 3wk using the M0 to M4 system, where M0=a claw free of signs of digital dermatitis; M1=a lesion <2cm that is not painful; M2=the ulcerative stage, with lesion diameter of >2cm, and painful to the touch; M3=the healing stage and covered by a scab; and M4=the chronic stage and characterized by dyskeratosis or proliferation of the surface that is generally not painful. McNemar's test statistic suggested that a statistically significant difference existed in the proportions of M1 and M2 lesions between the beginning and end of the study for both treatments. This indicates that each solution was effective in decreasing the proportion of M1 or M2 lesions from baseline to the last time point. A chi-square test calculated using PROC FREQUENCY of SAS (SAS Institute Inc., Cary, NC) indicated that no statistically significant relationship existed between the treatments among changes in digital dermatitis frequency from the baseline to the end of the study. Performance of the 2 footbath solutions was comparable throughout the study. No significant differences were observed between the copper sulfate and Provita Hoofsure Endurance.

Comparison of magnetic resonance imaging with standing cervical radiographs for evaluation of vertebral canal stenosis in equine cervical stenotic myelopathy.

REASONS FOR PERFORMING STUDY: The sensitivity and specificity of lateral cervical radiographs to evaluate horses suspected of cervical stenotic myelopathy (CSM) are limited by the assessment being restricted to the sagittal plane. OBJECTIVE: To determine whether magnetic resonance imaging (MRI) allows for a more accurate identification of stenosis than lateral cervical radiographs in horses with CSM. STUDY DESIGN: Case control study. METHODS: Nineteen Thoroughbred horses with CSM (17 males, 2 females, age 6-50 months) were compared to 9 control Thoroughbreds (6 males, 3 females, age 9-67 months). Ante mortem, the subjects had neurological examinations and standing cervical radiographs with sagittal ratios calculated from C3 to C7. Intact cervical column MRI scans and histological examinations of the spinal cord were performed post mortem. Morphometric parameters were measured on the vertebral canal, spinal cord and intervertebral foramen. RESULTS: Radiographic cervical canal height measurements categorised by standard minimal sagittal diameter intravertebral and intervertebral ratios produced several false positive and false negative determinations of canal stenosis as defined by spinal cord histopathology. Post mortem MRI measurements of canal area and cord canal area ratio more accurately predicted sites of cord compression in CSM cases. No differences in spinal cord measurements were observed when comparing CSM to control horses, but each of the vertebral canal parameters achieved significance at multiple sites. CONCLUSIONS: Vertebral canal area and cord canal area ratio are better parameters to predict the location of cervical canal stenosis compared to only the sagittal plane of canal height. Additional visual planes and measurements obtained by MRI, specifically vertebral canal area and the cord canal area ratio, will provide a more accurate method to identify regions of canal stenosis than lateral cervical radiographs. The development of MRI or computed tomography equipment capable of evaluating the cervical column of mature horses may substantially enhance evaluation of CSM patients. The Summary is available in Chinese - see Supporting information.

Influence of breed, milk production, season, and ambient temperature on dairy cow reticulorumen temperature.

Automatic monitoring of core body temperature in dairy cattle could be useful for identification of illness, heat stress, general physiological stress, and estrus. The SmartBolus (TenXSys Inc., Eagle, ID) system used a reticulorumen bolus to automatically record and transmit dairy cow temperatures. The objective of this research was to characterize the influence of milk yield (MY), time of day, breed, ambient temperature (AT), and season on reticulorumen temperatures (RT) in lactating dairy cows. Continuous RT and AT were collected by SmartBolus transponders every 15 min (96 records per d) from 93 cows (65 Holstein, 18 crossbred, and 10 Jersey) for 615 d. Mean (±SD) daily RT, AT, and MY were 40.14±0.32°C, 12.20±10.61°C, and 33.85±8.67 kg, respectively. The maximum and minimum RT were recorded at 2330 and 1000 h, respectively. Ambient temperature increased RT. Summer RT was significantly greater than spring, fall, or winter RT. The effect of MY on RT varied by breed, season, and AT. Crossbred RT was significantly lower than Holstein RT after adjusting for MY. Crossbred RT responded less to increasing AT than did Holstein RT, potentially indicating improved heat tolerance among these crossbred dairy cows. Reticulorumen temperature increased more dramatically for cows with greater milk yield as AT increased, demonstrating that high-producing cows are more susceptible to heat stress than low-producing cows. These results could be useful in interpretation of automatic temperature system data, heat stress management, and genetic selection of heat-tolerant cows.

Changes in teat-end hyperkeratosis after installation of an individual quarter pulsation milking system.

The objective of this study was to examine changes in teat-end hyperkeratosis (HK) in a herd transitioning from a standard pulsation milking system to an individual quarter pulsation milking system. The Milpro P4C (Milkline, Gariga di Podenzano, Italy) system stops milking individual quarters using an individual quarter pulsation milking system with 4 independent pulsation channels per cluster instead of 2. Teat-end HK was evaluated immediately after cluster removal using a scoring system where N signifies no ring; S signifies a smooth, raised ring; R signifies a rough ring; and VR signifies a very rough ring. Scorings were classified for 69 cows (48 Holstein, 12 crossbred, and 9 Jersey) on 5 dates relative to installation of the Milpro P4C system on April 28, 2011, as follows: April 7 (PRE1); April 21 (PRE2), May 12 (POST1), May 26 (POST2), and June 9 (POST3). Hyperkeratosis classifications were converted to numerical scores as follows: N=1, S=2, R=3, and VR=4. The MIXED procedure of SAS (SAS Institute Inc., Cary, NC) was used to evaluate fixed effects of age, breed, parity, teat position, and all interactions on teat-end HK score with variables repeated by scoring with cow within breed as subject. The effects of teat position and scoring × breed on teat-end HK score were significant. Holstein HK scores improved from PRE2 to POST3 (1.64 ± 0.09 and 1.42 ± 0.10, respectively), POST1 to POST3 (1.59 ± 0.10 and 1.41 ± 0.10, respectively), and POST2 to POST3 (1.53 ± 0.10 and 1.42 ± 0.10, respectively). Crossbred HK scores did not differ among scorings. Jersey HK scores worsened from POST1 to POST3 (1.32±0.21 and 1.63 ± 0.22, respectively). For all cows included in the final analysis, right front and left front HK scores were higher than right rear and left rear HK scores (1.58 ± 0.09, 1.62 ± 0.09, 1.37 ± 0.09, and 1.36 ± 0.09, respectively). However, a significant decrease in teat-end HK scores for Holsteins did occur from PRE1 to PRE2 (1.75 ± 0.10 and 1.63 ± 0.10, respectively) and may represent biological variation in teat-end HK over time unrelated to installation of the individual quarter pulsation system. Individual quarter pulsation milking systems may prevent overmilking and reduce HK in Holstein cows. Further research is warranted to understand the breed differences observed in this study.