Effects of dietary sources of vegetable fats on performance of dairy ewes and conjugated linoleic acid (CLA) in milk.

Two experiments were carried out to study the effects of supplementing the ration of lactating ewes with vegetable fats (sunflower oil, SO or hydrogenated palm oil, HPO; HIDROPALM (R)) on diet digestibility, milk yield and milk composition, and on the concentration of the conjugated linoleic acid (CIA) C18:2 cis-9 trans-11 and C18:1 trans-11 (vaccenic acid, VA) and other main fatty acids in milk fat. Treatments involved a control diet, without added oil, and 2 diets supplemented with either 12 g/kg SO or 12 g/kg HPO on a dry matter (DM) basis. In the first experiment, 6 non-pregnant, non-lactating Lacaune ewes were used following a 3 x 3 replicated Latin Square design. Addition of vegetable fat supplement to the diet increased digestibility of DM, organic matter (OM) and crude protein (CP), but did not affect that of the ether extract (EE), neutral detergent fibre (NDF) or acid detergent fibre (ADF). In the second experiment, 60 Lacaune dairy ewes mid-way through lactation (120 +/- 12 days in milk, 0.98 +/- 0.03 kg/day average milk yield) were divided into three equal-sized groups each of which was assigned to one of the three experimental diets for 4 weeks. Compared with the control treatment, supplementation with H PO increased milk yield and energy-corrected milk. But neither vegetable fat supplement modified percentages of fat and protein in milk. Supplementation with HPO increased C14:1, C16:1 and C16:0 content and reduced C18:0 and C18:1 cis-9 content in milk fat. Supplementation with SO increased the VA content in milk fat by 36% and that of cis-9 trans-11 CLA by 29% in comparison with the control diet. Supplementation with HPO led to milk fat with 15% more cis-9 trans-11 CLA than control milk. In conclusion, adding a moderate dose of HPO or SO to the diets increased CIA concentration in milk fat. Nevertheless, supplementation with SO was more effective than HPO in increasing CLA concentration in milk fat and reducing the atherogenicity index, improving milk quality from the human health standpoint

Seroprevalence of eastern equine encephalomyelitis virus in birds and larval survey of Culiseta melanura Coquillett during an interepizootic period in central Ohio

From June through August in 1999 and 2000, we conducted an avian serosurvey for eastern equine encephalomyelitis (EEE) virus at Killbuck Marsh Wildlife Area (KMWA), a focus of infection in central Ohio. We also monitored abundance of the suspected enzootic vector, Culiseta melanura Coquillett, in Brown’s Lake Bog, an adjacent wetland. Of the 363 birds of 30 species sampled in 1999, three gray catbirds (Dumetella carolinensis) were positive for antibodies to EEE virus, representing 1.2% of the avian samples and 4.2% of the gray catbirds sampled. Given these results and the abundance of gray catbirds at this site, this species became the focus of our sampling efforts in 2000. However, none of the 109 samples collected from 98 catbirds in 2000 was positive for the virus. Culiseta melanura adults were monitored using resting boxes and CDC CO2 light traps at both sites in 1999. Culiseta melanura larvae were monitored in 1999 and 2000 at Brown’s Lake Bog, the closest known source of this species, approximately 5km from the avian serosurvey site. We suggest that dry conditions reduced the breeding and abundance of Cs. melanura in 2000 and possibly the transmission of EEE virus at KMWA

Patterns of West Nile Virus Infection in Ohio Blue Jays: Implications for Initiation of the Annual Cycle

West Nile virus (WNV) was first detected in North America in New York City in 1999 and rapidly moved westward. Understanding the mechanisms by which the amplification cycle is reinitiated each year increases our ability to predict epizootics and geographic expansion of the disease. Such understanding is enhanced by knowledge of the patterns of infection in the vertebrate reservoir hosts. Blue jays (Cyanocitta cristata) may serve as reservoir hosts for WNV. We examined the influence of age and date on the prevalence of WNV in jay carcasses in Ohio during May–August 2002. Percent of carcasses that were infected increased significantly with time from 3% in May to more than 90% by August. We found no difference in prevalence between juvenile (nestlings and fledglings) and adult jays early in the season, which contradicts the expected pattern if the majority of the adults sampled in 2002 had been exposed to the virus in 2001. Therefore, jays infected in 2001 were unlikely to have been important in initiating the 2002 virus cycle in Ohio

West Nile Virus in Mosquitoes of Northern Ohio, 2003

From June 19, 2003 to August 18, 2003, we surveyed the mosquitoes of Oberlin, OH, for West Nile Virus (WNV) infection using reverse transcriptase-polymerase chain reaction. A total of 12,055 mosquitoes, representing 17 species or species groups and 4 genera, were collected in gravid traps at seven sites throughout the city, with Culex pipiens/restuans being the most abundant and showing the highest minimum infection rate (MIR) of 0.78. This represents a decrease in WNV enzootic activity from the previous year. Both Cx. pipiens/restuans abundance and MIR increased significantly with date. However, we found no correlation between Cx. pipiens/restuans abundance and MIR