Antibody Against Western Encephalitis Virus Occurring in the Serum of Garter Snakes (Colubridae: Thamnophis) in Saskatchewan

A study was made of feeding and temperature as factors affecting the appearance of western equine encephalitis (WEE) virus-neutralizing serum (VNS) antibodies in the serum of garter snakes (Thamnophis spp). Eighty snakes were collected in the field, held in captivity under controlled conditions, and bled at frequent intervals. The sera were examined by standard procedures for the presence of WEE VNS-antibodies. It was found that snakes held between 10-28°C showed conversion and intermittent WEE VNS-antibody appearance, whereas snakes held at 6°C showed a decline in titre. The appearance of WEE VNS-antibody was related to environmental temperature, or a temperature-controlled factor, and not to feeding.     

Sleep stage characteristics of long and short sleepers

The possibility of different sleep stage characteristics being associated with different sleep lengths was explored by comparing two groups of high school seniors, who characteristically slept 6(1/2) hours or less or who slept 8(1/2) hours or more, with an age-matched control group not selected on the basis of sleep length. All-night electroencephalography was used to examine the sleep stage characteristics of these groups. Compared with the unselected age-matched group, the short sleepers showed no significant diminution in their stage 4 (deep) or rapid eye movement (dream) sleep. The long sleepers were observed to obtain significantly more rapid eye movement sleep than did the other groups.     

Effect of Short-Term Restricted Food Intake on Canine Pseudopregnancy

A non-pharmaceutical, dietary option may be useful to manage clinical pseudopregnancy (PSP). To describe the effect of short-term food restriction on canine PSP, 16 privately owned, overtly pseudopregnant bitches were randomly assigned to one of the following groups: Limit-fed (increasing amounts of a restricted maintenance: 50%, 40%, 30% restriction for 2, 3 and 2 days respectively) during 7 days (n = 8) or Maintenance-fed of the same food and period (n = 8). The bitches were physically examined and blood samples were taken for prolactin and progesterone determinations on days 2, 5 and 8. By day 8, none of the bitches had completely regressed the condition although all (8/8) the animals of the Limit-fed and two (25%) of the Maintenance-fed group improved in condition decreasing mammary size and secretion (p < 0.05). No day or group effects were observed for serum prolactin and progesterone concentrations (>0.05). It is concluded that although an 8-day food restriction did not cure PSP, it seemed to hasten PSP signs involution in these bitches. No endocrine change was related to these clinical findings.     

Prediction of nutritive values in grass silages: I. Nutrient digestibility and energy concentrations using nutrient compositions and fermentation characteristics

Grass silages (n = 136) were selected from commercial farms across Northern Ireland according to their pH, ammonia nitrogen, DM, and predicted ME concentration. Each silage was offered to four sheep as a sole feed at maintenance feeding level to determine nutrient digestibility and urinary energy output. Dry matter concentration was determined as alcohol-corrected toluene DM and was subsequently used as the basis for all nutrient concentrations. The objectives were to use these data to examine relationships between nutritive value and nutrient concentration or fermentation characteristics in silages and then develop prediction equations for silage nutritive values using stepwise multiple regression techniques. The silages had a large range in quality (DM = 15.5 to 41.3%, ME = 7.7 to 12.9 MJ/kg of DM, pH = 3.5 to 5.5) and a relatively even distribution over the range. There was a positive relationship (P < 0.001) between silage GE and DE or ME concentration. Digestible OM in total DM (DOMD); ME/GE; and digestibility of DM, OM, and GE were positively related (P < 0.05) to CP, soluble CP, ether extract, lactic acid concentration, and lactic acid/ total VFA, whereas they were negatively related (P < 0.05) to ADF, NDF, lignin, individual VFA concentration, pH, and ammonia N/total N. Concentrations of DE and ME and digestibility of CP and NDF had similar relationships with those variables, although some relationships were not significant. Three sets of multiple prediction equations for DE and ME concentration; ME/ GE; DOMD; and digestibility of DM, OM, GE, CP, and NDF were therefore developed using three sets of predictors. The first set included GE, CP, soluble N/total N, DM, ash, NDF, lignin, lactic acid/total VFA, and ammonia N/total N; the second set excluded soluble N/ total N and lignin because they are not typically measured; the third set further excluded the fermentation data. The R2 values generally decreased with exclusion of predictors. The second and third sets of equations, except for NDF digestibility, were validated using the mean-square-prediction-error model and an independent grass silage data set published since 1977 (n = 17 [DM digestibility] to 28 [DOMD and OM digestibility]). The validation indicated that the equations developed in the present experiment could accurately predict DE and ME concentrations and DE/GE and ME/GE in grass silages.     

Prediction of nutritive values in grass silages: II. Degradability of nitrogen and dry matter using digestibility, chemical composition, and fermentation data

One hundred thirty-six perennial rye-grass silages with wide variations in quality were evaluated for N and DM degradability in three beef steers offered grass silage of medium quality ad libitum. The silages were incubated in the rumen of each animal in triplicate for 0, 6, 12, 24, 48, and 72 h, respectively. The disappearance rates of N or DM were used to calculate the readily soluble fraction ("a" value), potentially degradable fraction ("b" value), and the fractional degradation rate of"b" ("c" value). The effective degradability (P) of N or DM was then estimated assuming a ruminal outflow rate of 0.02, 0.05, or 0.08/h (P0.02, P0.05, or P0.08). The objective was to use these data to develop prediction equations for N and DM degradability in grass silages. There were considerable variations in "a," "b," and "c" values and the P0.02, P0.05, or P0.08 of N and DM (e.g., the P0.02 of N ranged from 75.0 to 93.4% and the P0.02 of DM from 51.5 to 82.5%). The P0.02, P0.05, or P0.08 of N and DM were negatively related (P < 0.001) to ADF, NDF, and lignin concentrations but positively related (P < 0.001) to protein fractions (CP, soluble CP, and true protein concentrations) and digestibility of DM, OM, GE, CP, and NDF and digestible OM in the total DM (measured with sheep). The N and DM degradability data were also positively related to silage lactic acid concentration, but the relationships between DM degradability data and pH, ammonia N/total N, and VFA concentration in silages were negative (P < 0.05). Several sets of prediction equations (linear and multiple) were thus developed for N and DM degradability using CP or NDF concentration, "a" value or digestibility data as primary predictors, together with or without other nutrient concentration and silage fermentation variables. All these relationships were highly significant (P < 0.001), and each predictor had a significant effect on the relationship (P < 0.05). The R2 values in multiple regression for N and DM degradability were generally over 0.70 and higher than in linear regression equations. Four equations were also developed to convert N and DM degradability at a given ruminal outflow rate, predicted using the above-mentioned equations, to their counterparts at any ruminal outflow rate (0.02 to 0.10/h), respectively.     

Carcinogenicity of bracken fern (Pteridium esculentum) in New Zealand

Bracken fern (Pteridium esculentum) was harvested from two sites LB and TB one of which (TB) was on a central North Island New Zealand farm where bovine enzootic haematuria (BEH) was known to occur. The fern was dried, ground and incorporated (25% w/w) into a pelleted diet and fed to female rats for a total of 162 days. Fifteen weeks later when the rats were autopsied it was found that numerous tumours, mainly of the ileum and urinary bladder were present in the animals fed the bracken fern from the TB site. Neoplasms were found in 85% of rats from the TB group compared with 11% in the LB group while only a single tumour (a haemangioma of the uterus) was observed in the controls. In all, there were neoplasms in 42, 5 and 1 organ/s from the TB, LB and control rat groups respectively (p<0.001). Analysis of the fern and pellets for ptaquiloside, the carcinogen in bracken fern, showed much higher levels present in the material from the TB site. There was 26 and 2270 microg ptaquiloside/g of dried fern and, for pellets from the same fern, 6.5 and 355 microg ptaquiloside/g of pellets, for one collection from the LB and TB sources respectively.     

Tetratrichomonas spp. and Pentatrichomonas hominis are not persistently detectable after intravaginal inoculation of estrous heifers

Virgin heifers (44) were intravaginally inoculated at estrus with low (10(6)) or high (10(8)) doses of live Tetratrichomonas sp., Pentatrichomonas hominis (P. hominis), or Tritrichomonas foetus (T. foetus). Controls were inoculated with Diamond's trypticase yeast extract maltose media. Genital infection was determined by culture of cervico-vaginal mucus (CVM) in Schneider's media and InPouch TF as well as by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP). The presence of trichomonads in fecal samples was determined by culture in Schneider's medium and PCR/RFLP. In CVM samples, tetratrichomonads were found by PCR/RFLP and Schneider's culture only sporadically at intermittent weeks. The presence of tetratrichomonads was not associated with the dose in the experimental vaginal inoculation since Tetratrichomonas sp. appeared more frequently in heifers inoculated with a low dose of tetratrichomonads than in heifers inoculated with a high dose of tetratrichomonads. Moreover, Tetratrichomonas spp. were isolated not only in heifers inoculated with tetratrichomonads but also in control heifers and in heifers inoculated with P. hominis. In feces, Tetratrichomonas spp. were frequently identified by culture in Schneider's and by PCR/RFLP in heifers of all groups. P. hominis was never found in CVM or feces by any method. Based on the common appearance of tetratrichomonads in feces and vaginal secretions, it appears that tetratrichomonads were detected periodically in the vagina of heifers as a consequence of repeated contamination from feces and not as a result of experimental infection. In summary, in this study, the strains of Tetratrichomonas sp. and P. hominis did not establish persistent infection in heifers.