G84-693 Protein Levels for Growing and Finishing Cattle

This NebGuide describes the use of nonprotein nitrogen and bypass protein sources to fulfill the protein requirements of growing and finishing steers, heifers and bulls. Protein supplementation can be an expensive feed cost for cattle producers. Through the use of nonprotein nitrogen (NPN) and bypass protein sources, however, these costs can be reduced. Bypass protein is the protein that escapes breakdown in the rumen and passes as is into the small intestine where it is digested and absorbed. Because NPN sources are usually the most economical sources of supplemental nitrogen, NPN should be used whenever possible. The potential for using NPN depends on the ability of the rumen microorganisms to synthesize protein, the bypass protein supplied by ration ingredients, and the protein requirement of the animal

Determinación del riesgo potencial de estrés térmico del ganado bovino en cuatro localidades del centro y sur de Chile

Datos climáticos del periodo diciembre a febrero de los años 1999 al 2007 provenientes de estaciones meteorológicas situadas en Curicó, Chillán, Temuco y Osorno fueron utilizados para calcular un índice temperatura-humedad ajustado por el efecto del viento y de la radiación (THIadj-max). Las variables climáticas utilizadas para calcular este índice incluyeron: velocidad del viento, temperatura máxima del aire, humedad relativa y un valor estimado de la radiación solar. Cuando los valores de THIadj-max fueron superiores a 75, estos días fueron considerados como indicadores de “alerta” y riesgo potencial de estrés térmico en el ganado. Adicionalmente, el impacto en la producción animal fue estimado sobre la base de pérdidas potenciales de producción de leche para cada localidad, utilizando dos ecuaciones para su estimación. Las localidades de la región central, Curicó y Chillán, presentaron valores promedios de THIadj-max similares (79,4 y 79,1, respectivamente), pero ambos superiores a las de la región sur (Temuco y Osorno 77,1 y 68,1, respectivamente; P 75 fue mayor en la región central. Asimismo, la producción de leche mostró un mayor potencial de pérdidas en las regiones centrales de Chile (1,5 a 4,3 y 1,2 a 3,6 L*vaca-1*d-1 para Curicó y Chillán, respectivamente). Por otra parte, las regiones del sur, Temuco y Osorno, presentaron menores pérdidas potenciales (0,9 a 2,6 y 0,1 a 0,6 L*vaca-1*d-1, respectivamente). En conclusión, el riesgo potencial de estrés térmico para el ganado bovino es mayor en Curicó y Chillán, es moderado en Temuco, y es mínimo en Osorno. Finalmente, la cuantificación del impacto directo que tiene el clima sobre la productividad y el bienestar de los bovinos en Chile necesita ser estudiada.Meteorological data from December to January of years 1999 to 2007 from weather stations located in four localities in Chile (Curicó, Chillán, Temuco and Osorno) were used to calculate the adjusted temperature-humidity index (THIadj-max). Climate variables used to calculate the index were: wind speed, air temperature, relative humidity and an estimated value of solar radiation. When the values of THIadj-max were greater than 75, those days were considered as alert and as potential risk of heat stress in cattle. Additionally, the impact of climate on animal production was assessed by means of potential losses in milk production for each locality estimated by two equations. The localities of Curicó and Chillán presented similar values of THIadj-max (79.4 and 79.1, respectively), and both were higher than those for Temuco and Osorno (77.1 and 68.1, respectively, P 75 was greater in the Central region. In addition, the estimated mean milk production loss was greater in the Central regions (1.5 to 4.3 and 1.2 to 3.1 L*cow-1*d-1 for Curicó and Chillán, respectively). Conversely, the Southern regions, Temuco and Osorno, presented lower potential losses with 0.9 to 2.6 and 0.1 to 0.6 L*cow-1*d-1, respectively. In conclusion, the potential risk of heat stress of cattle seems greater in Curicó and Chillán, moderate in Temuco and minimum in Osorno. Additional research is needed in the order to quantify the impacts of environmental conditions in productivity and welfare of cattle in Chile

G84-738 Management to Minimize Hay Waste

This NebGuide discusses harvest factors that affect hay yield and quality as well as ways to reduce losses during harvest, storage, and feeding. Hay is harvested, stored, and fed under a wide variety of conditions that influence both its yield and feed value. High quality hay is needed by animals that require high nutrient concentrations to reach desired levels of production. These include dairy cows, finishing beef cattle, fattening lambs, and race horses. Excellent hay management is required to produce the hay needed by these livestock. High quality hay is also used as a supplement to lower quality forages, such as crop residues. Hay of lower quality is nutritionally valuable, but should be used in other livestock production systems, such as the wintering of beef cows

Growth Promoting Agents and Season Effects on Blood Metabolite and Body Temperature Measures

To assess growth promoting agents efficacy among seasons, triiodothyronine, thyroxine, blood metabolites, and tympanic temperature were measured in summer and winter studies. Within each season, pens of heifers were assigned to one of six growth promotant treatments. Season by growth promotant treatment interactions (P \u3c 0.05) indicated that the combination of estrogen and trenbolone acetate increased triiodothyronine in the winter, whereas trenbolone acetate alone decreased both triiodothyronine and thyroxine in the winter. Maximum tympanic temperature was greater (P \u3c 0.01) in the summer than in the winter, while minimum tympanic temperature was lowered (P \u3c 0.01) in the summer. Changes in blood metabolite levels resulting from the use of growth promotants do not appear to substantially influence seasonal changes in body temperature

Effect of Altered Feeding and Sprinkling on Performance and Body Temperature of Steers Finished in the Summer

Effects of feeding time (800 vs 1400) and sprinkling on feedlot performance, body temperature, and mound microclimate were examined to determine their usefulness in reducing heat stress of feedlot steers. Feed conversion was improved overall for steers with access to sprinklers. Body temperature, early in the finishing period, was reduced by both sprinkling and afternoon feeding relative to steers fed at 800 h without access to sprinklers . Overall water intake was greater for steers fed at 800 without sprinkling than any other treatment

G84-738 Management to Minimize Hay Waste

This NebGuide discusses harvest factors that affect hay yield and quality as well as ways to reduce losses during harvest, storage, and feeding. Hay is harvested, stored, and fed under a wide variety of conditions that influence both its yield and feed value. High quality hay is needed by animals that require high nutrient concentrations to reach desired levels of production. These include dairy cows, finishing beef cattle, fattening lambs, and race horses. Excellent hay management is required to produce the hay needed by these livestock. High quality hay is also used as a supplement to lower quality forages, such as crop residues. Hay of lower quality is nutritionally valuable, but should be used in other livestock production systems, such as the wintering of beef cows

Pen Density and Straw Bedding During Feedlot Finishing

Two experiments evaluated effects of straw bedding (in sheltered and unsheltered facilities) and pen density (in unsheltered facilities) on cattle performance during winter/spring (mid-December to late March) seasons. Bedding had no effect on overall performance in the sheltered facilities, but performance improvements were noted from December through February in unsheltered facilities. Lowering pen density(increasing pen space per animal) improved performance and lowered mud condition scores on the animal and in the feedlot

Modeling Daily Water Intake in Cattle Finished in Feedlots

Simple regression and multiple regression analyses were conducted to estimate factors affecting daily water intake(DWI) of finishing cattle. Seasonal simple linear regression equations were very poor predicting DWI (r2 \u3c 0.15). Best results were obtained with the overall simple regression. The multiple regression analysis showed that daily minimum temperature (or THI), solar radiation, and dry matter intake were the most important factors affecting DWI in cattle finished in feedyards. The following prediction equation was developed: daily water intake, gal*d-1 = -0.52677+ (0.1229 *DMI, lb*d-1) + (0.01137*solar radiation, kcal*d-1) + (0.06529*daily minimum temperature, °F)

Effect of High Roughage and High Energy Diets on Body Temperature

Four heifers were used in two trials comparing the effect of high energy and high roughage diets on three body temperature measurements. Body temperatures were measured in the vagina, in the ear canal near the tympanic membrane, and in the rumen. The high roughage diet lowered all three measures of body temperatures as compared with the high energy diet. Vaginal, tympanic, and ruminal temperature all appeared to effectively measure body temperature as they followed the same diurnal cycle; however, ruminal temperatures were, on average, 0.5 to 1.4°F higher than other body temperature measures

Pen Surface Temperature as a Predictor of DailyWater Intake and Tympanic Temperature in Steers Finished in Feedlots

Adequate estimation of water demand in cattle production feed yards is of high importance, especially due to reduced water availability because of changes in rain precipitation patterns and amounts. The pen surface in feed yards receives and reflects solar radiation, affecting along with other factors the microclimate to which cattle are exposed. This study aimed to describe the relationship between the pen surface temperature with the daily water intake and the tympanic temperature of finishing steers. Climate variables, including solar radiation, air temperature, relative humidity, and wind speed plus pen surface temperature and soil temperature at 10.2 cm depth were recorded. Data were collected from a weather station located in the feedlot in Concord NE, whereas daily water intake was estimated from a set of experimental pens sharing a waterer in two adjacent pens. Simple and polynomial linear regressions were assessed from data collected in different experiments conducted from 2003 to 2006. Two models to predict daily water intake were developed for finishing steers using the pen surface temperature as the predictor variable. The first one included data for the period May-October (overall model) and the second one for the summer period (June-August). The best fit for the overall model was a quadratic fit (r2 = 0.86), whereas the best-fit model for the summer model was the cubic (r2 = 0.72). Subsequently, both models were validated with data from an independent experiment conducted in the summer of 2007 in the same facilities. Both models tended to slightly overestimate daily water intake when they were validated (14.6% and 12.6%, respectively). For tympanic temperature, the best-fit model was linear, explaining 76% of the observed variability. When the dataset was split into night-time and daytime the best-fit model for the night period was a quadratic one and a linear one for the daytime, both improving the explanation of the variability observed. In conclusion, pen surface temperature can be used to predict both daily water intake and tympanic temperature in feedlot steers without access to shade