Seroprevalence of Porcine Circovirus type 2 in swine herds in Trinidad and Tobago.

The seroprevalence of porcine circovirus type 2 (PCV2) in the swine population of Trinidad and Tobago was studied, focusing on the association between the seroprevalence of the virus and each of four variables: gender, age, group, farm size, and geographic location. Farms were classified as large (>1000 sows) or small (2 pigs to 250 sows); three age groups-nursery pigs (3 to 10 weeks, n=82), grower (11 to 22 weeks, n=107), and breeding animals(n=85) were studied. A multistage sampling design with non-proportional sampling between strata (farm sizes) was employed. A total of 274 serum samples were tested, collected from three large farms (n=109) and 109 randomly chosen small farms (n=165). Samples were tested using the PCV type 2 indirect fluorescent antibody test kit by VMRD (USA). Sixty-one percent of the farms tested were positive (2 large farms, 66 small farms). The overall seroprevalence of PCV2 was 62.0% (170/274) and after adjusting for non-proportional sampling between strata, was 70.3% ...

Seroprevalence of Porcine Circovirus type 2 in swine herds in Trinidad and Tobago.

The seroprevalence of porcine circovirus type 2 (PCV2) in the swine population of Trinidad and Tobago was studied, focusing on the association between the seroprevalence of the virus and each of four variables: gender, age, group, farm size, and geographic location. Farms were classified as large (>1000 sows) or small (2 pigs to 250 sows); three age groups-nursery pigs (3 to 10 weeks, n=82), grower (11 to 22 weeks, n=107), and breeding animals(n=85) were studied. A multistage sampling design with non-proportional sampling between strata (farm sizes) was employed. A total of 274 serum samples were tested, collected from three large farms (n=109) and 109 randomly chosen small farms (n=165). Samples were tested using the PCV type 2 indirect fluorescent antibody test kit by VMRD (USA). Sixty-one percent of the farms tested were positive (2 large farms, 66 small farms). The overall seroprevalence of PCV2 was 62.0% (170/274) and after adjusting for non-proportional sampling between strata, was 70.3% ...

Calving-to-conception interval of dairy cows in a farm in Trinidad and Tobago.

Factors affecting calving-to-conception interval (CCI) in dairy cows on a farm in Trinidad and Tobago were studied. Retrospective data from the period January 200 to December 2004 were collected from records (n=178) of the University Field Station dairy herd and analysed using a multivariable regression model. Predictor variables included: parity, season of calving [wet vs. dry- dry season (mean rainfall 48.8mm) runs from January to May and the wet season (mean rainfall 194.9mm) from June to December], presence or absence of periparturient disease (PPD), and milk yield. Milk production data were adjusted to an annual yield by correcting the yield between calving intervals to a 365-day production. The natural logarithm transformation of the CCI (LCCI) was fitted as the response of variable in a regression model. The regression coefficients for parity and season of calving were not significant and were 1.4 days longer than females without periparturient disease (P=0.04). Higher milk- producing cows had shorter CCIs. For each kilogramme increase in milk yield, there was a one-day decrease in CCI (P=0.0001). The adjusted R squared was 24% and the predictive regression equation was: LCCI=5.22+0.33 (PPD)-0.0001 (milk yield). The findings in this study support the need for more comprehensive investigations at national and regional levels in order to screen for other predictors in an effort to deliver better dairy herd programs health.

Calving-to-conception interval of dairy cows in a farm in Trinidad and Tobago.

Factors affecting calving-to-conception interval (CCI) in dairy cows on a farm in Trinidad and Tobago were studied. Retrospective data from the period January 200 to December 2004 were collected from records (n=178) of the University Field Station dairy herd and analysed using a multivariable regression model. Predictor variables included: parity, season of calving [wet vs. dry- dry season (mean rainfall 48.8mm) runs from January to May and the wet season (mean rainfall 194.9mm) from June to December], presence or absence of periparturient disease (PPD), and milk yield. Milk production data were adjusted to an annual yield by correcting the yield between calving intervals to a 365-day production. The natural logarithm transformation of the CCI (LCCI) was fitted as the response of variable in a regression model. The regression coefficients for parity and season of calving were not significant and were 1.4 days longer than females without periparturient disease (P=0.04). Higher milk- producing cows had shorter CCIs. For each kilogramme increase in milk yield, there was a one-day decrease in CCI (P=0.0001). The adjusted R squared was 24% and the predictive regression equation was: LCCI=5.22+0.33 (PPD)-0.0001 (milk yield). The findings in this study support the need for more comprehensive investigations at national and regional levels in order to screen for other predictors in an effort to deliver better dairy herd programs health.

MEDCARIB Evaluation of performance indices for broiler raised in conventional versus tunnel-ventilated houses and the cost effectiveness of the two types of housing in Barbados.

Retrospective data from 18 tunnel-ventilated and 41 conventional houses in Barbados were evaluated in order to compare the effects of the two types of housing using the following indices: feed conversion ratio at 1500 grammes (FCR 1500), European Production Efficiency Factor (EPEF), and net income per bird (NIPB). The data were obtained from the records of 200 and 282 grow-outs for tunnel-ventilated and conventional houses, respectively. The effects of season of placement and month of placement on the above performance variables were also evaluated. The analyses revealed that the performance variables NIPB, EPEF, and FCR 1500 were superior for tunnel -ventilated housing (P=0.02, 0.0001 respectively); were less variable from month to month for tunnel- ventilated housing; and except for NIPB, were better when birds were placed during the dry season (P=0.08, 0.0005 and 0.007 respectively). Financial anlaysis also showed that tunnel -ventilated house was more profitable venture than the conventional house. The net profit margin (15.38vs 3.59%) net profit per kg, (0.51 vs 0.12 BDS$, (BDS$1.00~ US $0.50)), and net profit per m squared (94.83vs13.13BDS$) were also higher for the tunnel-ventilated house.

MEDCARIB Evaluation of performance indices for broiler raised in conventional versus tunnel-ventilated houses and the cost effectiveness of the two types of housing in Barbados.

Retrospective data from 18 tunnel-ventilated and 41 conventional houses in Barbados were evaluated in order to compare the effects of the two types of housing using the following indices: feed conversion ratio at 1500 grammes (FCR 1500), European Production Efficiency Factor (EPEF), and net income per bird (NIPB). The data were obtained from the records of 200 and 282 grow-outs for tunnel-ventilated and conventional houses, respectively. The effects of season of placement and month of placement on the above performance variables were also evaluated. The analyses revealed that the performance variables NIPB, EPEF, and FCR 1500 were superior for tunnel -ventilated housing (P=0.02, 0.0001 respectively); were less variable from month to month for tunnel- ventilated housing; and except for NIPB, were better when birds were placed during the dry season (P=0.08, 0.0005 and 0.007 respectively). Financial anlaysis also showed that tunnel -ventilated house was more profitable venture than the conventional house. The net profit margin (15.38vs 3.59%) net profit per kg, (0.51 vs 0.12 BDS$, (BDS$1.00~ US $0.50)), and net profit per m squared (94.83vs13.13BDS$) were also higher for the tunnel-ventilated house.

Direct and correlated responses to selection for efficiency of lean gain in mice.

Improvement in feed efficiency when selection is based on gain:feed ratio has often been accompanied by a reduction in feed intake. The following four criteria were used in mass selection for improved lean gain efficiency in mice with an objective of evaluating changes in lean gain and intake: 1) gain deviation, animals selected had the greatest gain in fat-free mass (FFM) after adjustment to a constant intake; 2) intake deviation, mice selected had the least feed intake after adjustment to a constant gain in FFM; 3) intrinsic efficiency, similar to the second criterion except that adjustment was also made for average weight maintained during the period; and 4) a positive control that used the ratio of gain in FFM: feed intake as the selection criterion. A fifth line, in which a male and a female were selected at random from each litter, served as a negative control. Experimental animals were outbred mice of the CF1 strain. Two replicates of the five lines were included in the study. Twelve males and females were pair-mated within each line-replicate combination each generation. Feed disappearance was measured from 25 to 42 d. Mice were scanned to obtain an electrical conductivity measurement for prediction of FFM. After six generations of selection, realized heritabilities for gain:feed, gain deviation, intake deviation, and intrinsic efficiency were .00 +/- .04, .04 +/- .29, .35 +/- .08, and .28 +/- .06, respectively. There were no differences among lines for gain:feed ratio. The correlated response in feed intake reduction was significant in the intake deviation and intrinsic efficiency lines (-.17 +/- .05 and -.21 +/- .04 g x d(-1) x generation(-1), respectively). The realized genetic correlations between the ratio and gain deviation, intake deviation, and intrinsic efficiency were .83 +/- .15, .01 +/- .04, and .21 +/- .12, respectively. Litter size was depressed in all selected lines.