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The objective of this study was to evaluate the effects of daily weather parameters on feed intake in developing beef bulls. Weaned Angus bulls (n = 12; initial BW = 255.6 ± 5.6 kg) were acclimated to consuming a grain-based diet in a GrowSafe Model 6000 feed intake monitoring system in Prairie, MS. Then weather data were recorded each minute on-site by an automated system during a 70-d feeding period starting on May 16, 2016. Daily minimum and maximum temperature, relative humidity, and barometric pressure data were classified into LOW (< -0.5 SD), MODERATE (-0.5 to 0.5 SD), and HIGH ( > 0.5 SD) levels. Precipitation data were classed as no rain or rain based on the presence or absence of daily precipitation. Data were evaluated using the PROC MIXED procedure of SAS specific for repeated measures with LSMEANS separation evaluated at a = 0.05. Daily feed intake was affected by the interaction of daily maximum temperature and maximum relative humidity (P < 0.01) such that, unexpectedly, bulls consumed 1.7 kg more feed at the HIGH levels of both maximum temperature ( > 34.2°C) and relative humidity ( > 98.1%) versus the LOW levels ( < 31.2°C and < 93.1%, respectively) of these variables. The interaction of daily minimum temperature and minimum humidity (P < 0.01) followed a similar feed intake pattern in which bulls consumed 1.3 kg more feed at the HIGH levels of both minimum temperature ( > 21.8°C) and relative humidity ( > 48.2%) as compared to the LOW levels ( < 18.8°C and < 38.8%, respectively) of these variables. Feed intake increased (P = 0.01) (9.4, 10.0, and 10.7 kg) as maximum barometric pressure level decreased, respectively, from > 765.7, 763.7 to 765.7, and < 763.7 mm Hg. Feed intake was comparable between the HIGH and MODERATE daily minimum barometric pressure levels but was 1.2 kg less (P < 0.01) at the LOW level ( < 760.5 mm Hg) relative to the HIGH ( > 762.5 mm Hg) and MODERATE (760.5 to 762.5 mm Hg) levels. On days when it rained, feed intake was depressed (P < 0.01) by 0.9 kg. These data suggest that environmental conditions contribute to daily feed intake fluctuations in growing cattle and that a combination of several weather parameters are involved in shifts in feeding behavior responses. [ABSTRACT FROM AUTHOR]

The study objective was to evaluate the effects of hair shedding score and hair coat color on vaginal temperature (VT) of calves during heat stress. Weaned Bos taurus beef heifers (n = 32; BW = 282 ± 6.4 kg) were assigned to a hair coat color class (BLACK; RED; or LIGHT, where LIGHT = yellow or gray) and evaluated for hair shedding score. Hair coat was subjectively scored on a 1 to 5 scale (1 = slick summer coat, 5 = no shedding). Vaginal temperatures were recorded at 5-min intervals during a 19-d study in July and August 2016. Calves were randomly assigned to one of four 2.02-ha pastures in Prairie, MS with equivalent shade allotment and balanced by hair color and shedding score. Environmental temperature and humidity data loggers were placed in each pasture. Temperature data were evaluated using the PROC MIXED procedure of SAS specific for repeated measures with LSMEANS separation evaluated at α = 0.05 using the PDIFF option. Throughout the study, the mean environmental temperature was 27.75°C, and mean relative humidity was 82.81%. There was an interaction between color and hair shedding score (P = 0.02). There was no difference between hair score 1 and 2 (P = 0.39) but there was a difference between hair scores 1 and 3 (P < 0.0001) and hair scores 2 and 3 (P < 0.0001) for all hair colors. In animals having a hair score of 1, RED animals had elevated VT compared to BLACK (P = 0.0003). There was a tendency for increased VT in RED animals compared to LIGHT (P = 0.07). In heifers with a hair score of 2, there was a tendency for increased VT in RED heifers compared to LIGHT (P = 0.08) and an increase in VT in RED compared to BLACK (P = 0.0012). There was no difference between LIGHT and RED heifers in hair score 3 (P = 0.14); however, they had elevated VT in comparison to BLACK (P < 0.0035). Future research endeavors are warranted to further explore the observed interactions of hair coat color and shedding score on beef calf body temperature in the Southeastern United States. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of daily weather parameters on feed intake in developing beef bulls. Weaned Angus bulls (n = 12; initial BW = 255.6 ± 5.6 kg) were acclimated to consuming a grain-based diet in a GrowSafe Model 6000 feed intake monitoring system in Prairie, MS. Then weather data were recorded each minute on-site by an automated system during a 70-d feeding period starting on May 16, 2016. Daily minimum and maximum temperature, relative humidity, and barometric pressure data were classified into LOW ( < -0.5 SD), MODERATE (-0.5 to 0.5 SD), and HIGH ( > 0.5 SD) levels. Precipitation data were classed as no rain or rain based on the presence or absence of daily precipitation. Data were evaluated using the PROC MIXED procedure of SAS specific for repeated measures with LSMEANS separation evaluated at a = 0.05. Daily feed intake was affected by the interaction of daily maximum temperature and maximum relative humidity (P < 0.01) such that, unexpectedly, bulls consumed 1.7 kg more feed at the HIGH levels of both maximum temperature ( > 34.2°C) and relative humidity ( > 98.1%) versus the LOW levels ( < 31.2°C and < 93.1%, respectively) of these variables. The interaction of daily minimum temperature and minimum humidity (P < 0.01) followed a similar feed intake pattern in which bulls consumed 1.3 kg more feed at the HIGH levels of both minimum temperature ( > 21.8°C) and relative humidity ( > 48.2%) as compared to the LOW levels ( < 18.8°C and < 38.8%, respectively) of these variables. Feed intake increased (P = 0.01) (9.4, 10.0, and 10.7 kg) as maximum barometric pressure level decreased, respectively, from > 765.7, 763.7 to 765.7, and < 763.7 mm Hg. Feed intake was comparable between the HIGH and MODERATE daily minimum barometric pressure levels but was 1.2 kg less (P < 0.01) at the LOW level ( < 760.5 mm Hg) relative to the HIGH ( > 762.5 mm Hg) and MODERATE (760.5 to 762.5 mm Hg) levels. On days when it rained, feed intake was depressed (P < 0.01) by 0.9 kg. These data suggest that environmental conditions contribute to daily feed intake fluctuations in growing cattle and that a combination of several weather parameters are involved in shifts in feeding behavior responses. [ABSTRACT FROM AUTHOR]

The study objective was to evaluate the effects of hair shedding score and hair coat color on vaginal temperature (VT) of calves during heat stress. Weaned Bos taurus beef heifers (n = 32; BW = 282 ± 6.4 kg) were assigned to a hair coat color class (BLACK; RED; or LIGHT, where LIGHT = yellow or gray) and evaluated for hair shedding score. Hair coat was subjectively scored on a 1 to 5 scale (1 = slick summer coat, 5 = no shedding). Vaginal temperatures were recorded at 5-min intervals during a 19-d study in July and August 2016. Calves were randomly assigned to one of four 2.02-ha pastures in Prairie, MS with equivalent shade allotment and balanced by hair color and shedding score. Environmental temperature and humidity data loggers were placed in each pasture. Temperature data were evaluated using the PROC MIXED procedure of SAS specific for repeated measures with LSMEANS separation evaluated at n = 0.05 using the PDIFF option. Throughout the study, the mean environmental temperature was 27.75°C, and mean relative humidity was 82.81%. There was an interaction between color and hair shedding score (P = 0.02). There was no difference between hair score 1 and 2 (P = 0.39) but there was a difference between hair scores 1 and 3 (P < 0.0001) and hair scores 2 and 3 (P < 0.0001) for all hair colors. In animals having a hair score of 1, RED animals had elevated VT compared to BLACK (P = 0.0003). There was a tendency for increased VT in RED animals compared to LIGHT (P = 0.07). In heifers with a hair score of 2, there was a tendency for increased VT in RED heifers compared to LIGHT (P = 0.08) and an increase in VT in RED compared to BLACK (P = 0.0012). There was no difference between LIGHT and RED heifers in hair score 3 (P = 0.14); however, they had elevated VT in comparison to BLACK (P < 0.0035). Future research endeavors are warranted to further explore the observed interactions of hair coat color and shedding score on beef calf body temperature in the Southeastern United States. [ABSTRACT FROM AUTHOR]