Ecological chemistry and the palatability spectrum

A new bioassay for comparing the palatability to avian predators of monarch butterflies reared on various asclepiadaceous food plants containing cardiac glycosides indicates a palatability spectrum. The monarchs reared on one plant species are six times as emetic as those fed another, while those raised on an asclepiad which lacks cardiac glycosides are not emetic at all.     

Influence of pregnancy on body weight, ruminal characteristics, and visceral organ mass in beef heifers

Crossbred heifers (initially 24 mo, approximate age and 378 +/- 32.1 kg BW) were used to evaluate the influence of pregnancy and advancing gestation on DMI, BW, carcass weight, ruminal characteristics, and visceral organ mass. Heifers (naturally serviced (n = 22; nonpregnant controls, n = 17), were grouped in common pens. Heifers were provided corn silage and hay-based diets formulated to provide 0.45 kg of ADG. Treatments were pregnancy and nonpregnancy; pregnant and nonpregnant heifers were slaughtered on d 40, 120, 200, and 270. Live weight at slaughter and BW change throughout the trial were not influenced by pregnancy (P > 0.1). Carcass weight per unit of BW was decreased due to pregnancy (P < 0.05) and an interaction was found in eviscerated BW (EvBW; P < 0.1), with the pregnant heifers having greater live weights, carcass weights, and EvBW at the d-200 slaughter period. Ruminal fluid fill and total fill (g/kg BW) declined as slaughter period advanced, resulting in the pregnant heifers having less fill at d 270 (P< 0.07). However, ME intake was not different between pregnant and nonpregnant heifers (P > 0.1) at any of the slaughter periods. Heart mass responded differently when nonpregnant and pregnant were analyzed over time and an interaction was detected as slaughter period advanced (P < 0.1). Liver, duodenum, jejunum, and large intestinal mass were not responsive to pregnancy (P > 0.1). Data indicate that ruminal fill is altered by pregnancy but visceral organ mass is not greatly changed by treatment.     

Prevalence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in ovine from São Paulo State, Brazil

Serum samples from 597 sheep from S?o Paulo State, in the southeastern region of Brazil, were tested to determine the prevalence of antibodies directed against Toxoplasma gondii (> or = 1:64) and Neospora caninum (> or = 1:50) using the indirect fluorescent antibody test (IFAT). The animals were divided into three groups based on their age: < or = 1 year, 1-4 years, and > or = 4 years. Antibodies to T. gondii were observed in 34.7% of the samples with titers ranging from 64 to 16,384 and IgG antibodies directed against N. caninum were observed in 9.2%, with titers ranging from 50 to 3200. Only 3.5% of the sheep were positive for both agents. All farms had at least one positive animal for T. gondii, and 26 of the 30 farms had at least one positive animal for N. caninum. An association between seroprevalence and age was observed for T. gondii (P = 0.001), but not to N. caninum (P = 0.343). It was not possible to associate seroprevalence to T. gondii and the presence of domestic or feral cats, since in all farms there was at least one positive sheep. There was no association between seropositivity to N. caninum and the presence of domestic (P = 1.000) and feral dogs (P = 0.550).     

Development. Survival is impossible without an editor

RNA editing is a fascinating phenomenon that is found in both animal and plant cells. By converting an adenosine base to an inosine (which behaves like guanosine) in RNA that has already been transcribed, certain RNA sequences (and hence the amino acids they encode) are altered. In a Perspective, Keegan, Gallo and O'Connell explore new results showing that activity of the editing enzyme ADAR1 is crucial for normal development of red blood cells in mouse embryos.