PSI-14 Feeding β-agonists under heat stress conditions in feedlot cattle

Abstract Red Angus steers (n = 24; 260 ± 25 kg) were used to analyze the effects of supplementation of zilpaterol hydrochloride (ZH) under heat stress conditions on respiration rate (RR), rectal temperature (RT), growth performance (GP), and carcass traits (CT). Steers were randomly assigned to a 2 x 2 factorial treatment arrangement (n = 6/group) with factors including heat stress (HS; THI=71 to 83) or thermal neutral (TN; THI=27 to 39) conditions and with/without supplementation of ZH (0 or 8.38 mg/kg/d on 88% DM basis). Steers were provided 9 d to acclimate to tie stalls rooms under TN conditions before starting the study. TN steers were pair-fed to the average daily dry matter intake (DMI) of HS steers. Ad libitum water consumption (WC) was recorded daily. HS and TN steers were harvested on d 22 and 23, respectively. By design, DMI was not different between environments (P = 0.43). DMI also did not differ between supplement groups (P = 0.31). RT, RR, and WC were greater (P < 0.01) in HS steers compared to TN steers. There was a supplement by environment interaction (P = 0.02) for RT, as HS steers fed ZH had lower RT than HS control steers (39.1 vs 39.5 ℃). ADG was 20% higher (P = 0.04) in HS steers compared to TN steers. CT did not differ (P = >0.05) due to environment, treatment, or interactions between environment and ZH supplementation. Our results suggest that feedlot steers under our experimental conditions display some sensitivity to HS through GP, RR, and RT, however, this did not translate to an impact on CT. Furthermore, ZH supplementation under HS conditions appears to impact thermoregulatory responses positively, yet this did not impact GP or CT.

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PSII-19 Effect of zinc and chromium supplementation on performance and carcass characteristics in feedlot steers

Journal of Animal Science ◽

10.1093/jas/skaa278.703 ◽

2020 ◽

Vol 98 (Supplement_4) ◽

pp. 400-401

Author(s):

Harrison D Hallmark ◽

Joanis T Zervoudakis ◽

Juliana Akamine Torrecilhas ◽

Luciana K Hatamoto-Zervoudakis ◽

Henrique Toller ◽

...

Keyword(s):

Dry Matter ◽

Carcass Characteristics ◽

Dietary Treatment ◽

Feedlot Cattle ◽

The Other ◽

Carcass Weight ◽

Dry Matter Intake ◽

Marbling Score ◽

Feedlot Steers ◽

Supplemental Zinc

Abstract One hundred and sixty-five crossbred steers were used in this experiment to investigate the influence of supplemental zinc (Zn) and chromium (Cr) on performance and carcass characteristics of feedlot steers fed steam-flaked corn-based finishing diet. Steers were blocked by initial BW (518.9 ± 8.4 kg) within cattle source (2 sources) and housed in pens containing 6–7 steers per pen. Pens within blocks were randomly assigned to treatments in a 2 x 2 factorial arrangement, with factors being: 30 or 90 mg of Zn/kg DM and 0.0 or 0.25 mg Cr/kg DM. Treatments consisted of: 1) 30 mg Zn/kg DM; 2) 90 mg Zn/kg DM; 3) 30 mg Zn + 0.25 mg Cr/kg DM; and 4) 90 mg Zn/kg + 0.25 mg Cr/kg DM. Zinc was supplemented as ZnSO4 and Cr supplemented as Cr propionate. Steers were individually weighted on 2 consecutive days prior to initiating dietary treatment and on 2 consecutive days at the end of the experiment. Dietary treatment were initiated 64 days prior to slaughter (total days on feed = 240). All cattle were transported to a commercial abattoir on the same day and slaughtered. Steers receiving supplemental Cr had greater final BW (P < 0.02) and ADG (P < 0.03) when compared to non-Cr supplemented steers. Additionally, hot carcass weight (P < 0.005) and marbling score (P < 0.03) were greater (P < 0.005) for steers receiving 30 mg Zn/kg DM + 0.25 mg Cr/kg DM when compared with all other treatments. Dry matter intake, morbidity and mortality, and all the other carcass measurements were similar across treatments. These data indicate that under the conditions of this experiment, Zn and Cr supplementation may influence feedlot cattle growth and carcass characteristics.

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214 The effects of an 18-hour transit or complete feed and water restriction on feed bunk displacements and need preferences in growing feedlot steers

Journal of Animal Science ◽

10.1093/jas/skaa054.007 ◽

2020 ◽

Vol 98 (Supplement_3) ◽

pp. 5-5

Author(s):

Katie J Heiderscheit ◽

Erin Deters ◽

Alyssa Freestone ◽

Joshua Peschel ◽

Stephanie L Hansen

Keyword(s):

Repeated Measures ◽

Dry Matter ◽

Treatment Time ◽

Dry Matter Intake ◽

Feed Restriction ◽

Water Restriction ◽

Trained Observer ◽

Aggressive Interactions ◽

Feedlot Steers ◽

Effect Of Treatment

Abstract The objective was to investigate effects of 18 h feed and water restriction or transit on cattle behavior. Angus-cross steers (36; 353 ± 33 kg) were housed in pens of 6 and assigned to treatments: control (CON), full access to feed and water; deprived (DEPR), no feed or water for 18 h; or transported (TRANS), trucked for 18 h. Individual BW (n = 12 steers/treatment) was recorded on d 0, 1, 3, 8, and 14, and individual dry matter intake (DMI) was determined via GrowSafe bunks. Bunk displacements on d 1 were recorded for each pen (n = 2 pens/treatment) by one trained observer continuously for 2 h in 10 min intervals via video analysis. Steer need preferences were assessed as time individuals took to perform behaviors (eat, drink, lay) after treatments ended on d 1. Data were analyzed using Proc Mixed of SAS with fixed effect of treatment; displacements, BW, and DMI were analyzed as repeated measures. Upon return to pens, time to eat or drink did not differ between DEPR and TRANS (P ≥ 0.17), but time to lay was 70.5 min for DEPR vs. 16.5 min for TRANS (P = 0.01). Displacements were greater for DEPR than CON or TRANS during the first 90 min after accessing feed, while CON displaced more frequently than TRANS for the first 30 min (treatment × time; P = 0.02). While DMI for TRANS was not recovered until d 2, DEPR and CON had similar DMI on d 1 (treatment × day; P < 0.01). Similarly, TRANS BW were, and DEPR tended to be, lesser than CON on d 1; however, BW among treatments were not different on other days (treatment × day; P < 0.01). Thus, restricting feed increases aggressive interactions at the bunk and cattle trucked long distances are quick to lay down when allowed. These behaviors should be considered when managing an unintentional feed restriction event or receiving cattle into the feedlot.

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Wetting and the physiological responses of grain-fed cattle in a heated environment

Australian Journal of Agricultural Research ◽

10.1071/ar03110 ◽

2004 ◽

Vol 55 (3) ◽

pp. 253 ◽

Cited By ~ 24

Author(s):

John B. Gaughan ◽

M. Shane Davis ◽

Terry L. Mader

Keyword(s):

Heat Stress ◽

Experimental Design ◽

Rectal Temperature ◽

Environmental Conditions ◽

Dry Matter ◽

Physiological Responses ◽

Dry Matter Intake ◽

Metabolic Responses ◽

Hot Days ◽

Carry Over

A controlled crossover experimental design was used to determine the effect of altered water sprinkling duration on heifers subjected to heat stress conditions. Heifers were subjected to 3 days of thermoneutral conditions followed by 3 days of hot conditions accompanied by water sprinkling between 1300 and 1500 h (HOT1–3). Then on the following 2 days (HOT4–5), environmental conditions remained similar, but 3 heifers were sprinkled between 1200 and 1600 h (WET) and 3 were not sprinkled (NONWET). This was followed by a 1-day period (HOT6) in which environmental conditions and sprinkling regimen were similar to HOT1–3. Rectal temperature (RT) was collected hourly, and respiration rate (RR) was monitored every 2 h on HOT Days 2, 4, 5, and 6. Dry matter intake and rate of eating were also determined. Sprinkling reduced RR and RT (P < 0.01) of all heifers during HOT1–3. During HOT4–5, WET heifers had lower (P < 0.05) RT than NONWET from 1300 to 700 h and lower RR from 1400 to 2000 h. Dry matter intake of NONWET heifers was reduced by 30.6% (P < 0.05) during HOT4–5 and by 51.2% on HOT6. On HOT4–5 the dry matter intakes of WET heifers were similar to intakes under thermoneutral conditions. During HOT6, RT was again reduced following sprinkling in all heifers. Comparison of RT and RR of NONWET and WET heifers on HOT1–3 v. HOT6 revealed that under similar environmental conditions, NONWET heifers had increased RT, partially due to carry-over from HOT4–5. However, NONWET heifers had 40% lower feed intake but tended to have lower RR on HOT6 v. HOT1–3. Only RR of WET heifers was greater on HOT6, possibly a result of switching from a 4-h back to a 2-h sprinkling period, while maintaining a 62% greater intake (5.80 v. 3.58 kg/day) than NONWET heifers during this time. Results suggest that inconsistent cooling regimens may increase the susceptibility of cattle to heat stress and elicit different physiological and metabolic responses.

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Effects of zilpaterol hydrochloride and soybean oil supplementation on feedlot performance and carcass characteristics of hair-breed ram lambs under heat stress conditions

Journal of Animal Science ◽

10.2527/jas.2012-6214 ◽

2014 ◽

Vol 92 (3) ◽

pp. 1184-1192 ◽

Cited By ~ 7

Author(s):

J. L. Dávila-Ramírez ◽

U. Macías-Cruz ◽

N. G. Torrentera-Olivera ◽

H. González-Ríos ◽

S. A. Soto-Navarro ◽

...

Keyword(s):

Heat Stress ◽

Soybean Oil ◽

Carcass Characteristics ◽

Stress Conditions ◽

Feedlot Performance ◽

Zilpaterol Hydrochloride ◽

Ram Lambs

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Enzyme activity in the micropylar region of Melanoxylon brauna Schott seeds during germination under heat stress conditions

Journal of Seed Science ◽

10.1590/2317-1545v42229988 ◽

2020 ◽

Vol 42 ◽

Author(s):

Marcone Moreira Santos ◽

Eduardo Euclydes de Lima e Borges ◽

Glauciana da Mata Ataíde ◽

Raquel Maria de Oliveira Pires ◽

Debora Kelli Rocha

Keyword(s):

Enzyme Activity ◽

Heat Stress ◽

Seed Germination ◽

Pectin Methylesterase ◽

Stress Conditions ◽

Southeastern Brazil ◽

Experimental Conditions ◽

Mannanase Activity ◽

Ecological Importance ◽

The Many

Abstract: Recent studies indicate that global temperatures will rise substantially in the 21st century, leading to the extinction of several plant species, as plant metabolism and germination are greatly affected by temperature. Melanoxylon brauna, a tree species native to the Atlantic Forest that occurs from northeastern to southeastern Brazil, is one of the many species threatened by global warming. Despite the economic and ecological importance of M. brauna, studies investigating the influence of heat stress on seed germination and biochemical responses are still incipient. This study aimed to evaluate enzyme activity in the micropylar region of M. brauna seeds during germination under heat stress conditions. Endo-β-mannanase, α-galactosidase, polygalacturonase, pectin methylesterase, pectin lyase, total cellulase, 1,3-β-glucosidase, and 1,4-β-glucosidase activities were determined in micropyles of seeds imbibed for 24, 48 and 72 h at 25, 35 and 45 °C. Seed germination was highest at 25 °C. Endo-β-mannanase activity was not detected under any of the experimental conditions, but imbibition temperature had a significant effect on the activity of all other enzymes.

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Critical Temperature-Humidity Index Thresholds for Dry Cows in a Subtropical Climate

Frontiers in Animal Science ◽

10.3389/fanim.2021.706636 ◽

2021 ◽

Vol 2 ◽

Author(s):

Véronique Ouellet ◽

Izabella M. Toledo ◽

Bethany Dado-Senn ◽

Geoffrey E. Dahl ◽

Jimena Laporta

Keyword(s):

Heat Stress ◽

Respiration Rate ◽

Rectal Temperature ◽

Dry Matter ◽

Dry Matter Intake ◽

Subtropical Climate ◽

Dry Period ◽

Environmental Indices ◽

Temperature Humidity Index ◽

Humidity Index

The effects of heat stress on dry cows are profound and significantly contribute to lower overall welfare, productivity, and profitability of the dairy sector. Although dry cows are more thermotolerant than lactating cows due to their non-lactating state, similar environmental thresholds are currently used to estimate the degree of heat strain and cooling requirements. Records of dry cow studies conducted over 5 years in Gainesville, Florida, USA were pooled and analyzed to determine environmental thresholds at which dry cows exhibit signs of heat stress in a subtropical climate. Dry-pregnant multiparous dams were actively cooled (CL; shade of a freestall barn, fans and water soakers, n = 107) or not (HT; shade only, n = 111) during the last 7 weeks of gestation, concurrent with the entire dry period. Heat stress environmental indices, including ambient temperature, relative humidity, and temperature-humidity index (THI), and animal-based indices, including respiration rate, rectal temperature and daily dry matter intake were recorded in all studies. Simple correlations were performed between temperature-humidity index and each animal-based indicator. Differences in respiration rate, rectal temperature and dry matter intake between treatments were analyzed by multiple regression. Using segmented regression, temperature-humidity thresholds for significant changes in animal-based indicators of heat stress were estimated. Stronger significant correlations were found between the temperature-humidity index and all animal-based indices measured in HT dry cows (−0.22 ≤ r ≤ 0.35) relative to CL dry cows (−0.13 ≤ r ≤ 0.19). Although exposed to similar temperature-humidity index, rectal temperature (+0.3°C; P < 0.001) and respiration rate (+23 breaths/min; P < 0.001) were elevated in HT dry cows compared with CL cows whereas dry matter intake (−0.4 kg of dry matter/d; P = 0.003) was reduced. Temperature-humidity index thresholds at which respiration rate and rectal temperature began to change were both determined at a THI of 77 in HT dry cows. No significant temperature-humidity threshold was detected for dry matter intake. At a practical level, our results demonstrate that dry cow respiration rate and rectal temperature increased abruptly at a THI of 77 when provided only shade and managed in a subtropical climate. Therefore, in the absence of active cooling, dry cows should be closely monitored when or before THI reaches 77 to avoid further heat-stress related impairments during the dry period and the subsequent lactation and to mitigate potential carry-over effects on the offspring.

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Intake, physiological parameters and behavior of Angus and Nellore bulls subjected to heat stress

Semina Ciências Agrárias ◽

10.5433/1679-0359.2015v36n6supl2p4565 ◽

2015 ◽

Vol 36 (6Supl2) ◽

pp. 4565 ◽

Cited By ~ 6

Author(s):

Ériton Egidio Lisboa Valente ◽

Mario Luiz Chizzotti ◽

Cristiane Viol Ribeiro de Oliveira ◽

Matheus Castilho Galvão ◽

Silas Sebastião Domingues ◽

...

Keyword(s):

Heat Stress ◽

Water Intake ◽

Dry Matter ◽

Daily Intake ◽

High Heat ◽

Dry Matter Intake ◽

Effect Of Temperature ◽

Period 2 ◽

Humidity Index ◽

And Behavior

Genetics differences between breeds may determine the tolerance to high temperature, effect dry matter intake and consequently cattle performance. The effect of temperature and humidity index (THI) on diurnal, nocturnal and daily intake, water intake, physiologic parameters and behavior of Nellore (B. indicus) and Angus (B. taurus) bulls were evaluated. Eight Angus and eight Nellore young bulls (337±7.4 kg and 16 months of age) were allocated in two climate-controlled rooms for 32 days. In the period 1, all bulls were housed in thermoneutral conditions (TN, THI = 72.6) for 10 days. In period 2 (10 days), four Angus and four Nellore bulls were subjected to low heat stress (LHS, THI = 76.4) in daytime, and four Angus and four Nellore bulls were subjected to high heat stress (HHS, THI = 81.5) in daytime. The diurnal and daily dry matter intake (DMI) of Nellore were not affected (P>0.05) by heat stress. However, Angus bulls decreased diurnal DMI by 24% and daily DMI decreased (P<0.05) by 15% on HHS. In TN Angus bulls had higher (P<0.05) daily DMI (36.2 g/kg of BW) than Nellore (29.1 g/kg of BW), but in HHS they had similar (P>0.05) daily DMI (31.6 and 30.2 g/kg of BW, respectively). We observed an increase (P<0.05) in respiratory frequency, but water intake was not affected (P>0.05) by heat stress. The heart rate decreased (P<0.05) with heat stress. No differences were found (P>0.05) in feeding behavior. Therefore, THI stress threshold should distinct for Angus and Nellore bulls. The use of feed intake information may improve the prediction of thermic discomfort on specific climate condition.

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Effect of Heat Stress on Bacterial Composition and Metabolism in the Rumen of Lactating Dairy Cows

Animals ◽

10.3390/ani9110925 ◽

2019 ◽

Vol 9 (11) ◽

pp. 925

Author(s):

Zhao ◽

Min ◽

Zheng ◽

Wang

Keyword(s):

Heat Stress ◽

Dairy Cows ◽

Milk Production ◽

Dry Matter ◽

16S Rrna Genes ◽

Dry Matter Intake ◽

Rrna Genes ◽

Bacterial Composition ◽

Rumen Ph ◽

Lactating Dairy Cows

Heat stress negatively impacts the health and milk production of dairy cows, and ruminal microbial populations play an important role in dairy cattle’s milk production. Currently there are no available studies that investigate heat stress-associated changes in the rumen microbiome of lactating dairy cattle. Improved understanding of the link between heat stress and the ruminal microbiome may be beneficial in developing strategies for relieving the influence of heat stress on ruminants by manipulating ruminal microbial composition. In this study, we investigated the ruminal bacterial composition and metabolites in heat stressed and non-heat stressed dairy cows. Eighteen lactating dairy cows were divided into two treatment groups, one with heat stress and one without heat stress. Dry matter intake was measured and rumen fluid from all cows in both groups was collected. The bacterial 16S rRNA genes in the ruminal fluid were sequenced, and the rumen pH and the lactate and acetate of the bacterial metabolites were quantified. Heat stress was associated with significantly decreased dry matter intake and milk production. Rumen pH and rumen acetate concentrations were significantly decreased in the heat stressed group, while ruminal lactate concentration increased. The influence of heat stress on the microbial bacterial community structure was minor. However, heat stress was associated with an increase in lactate producing bacteria (e.g., Streptococcus and unclassified Enterobacteriaceae), and with an increase in Ruminobacter, Treponema, and unclassified Bacteroidaceae, all of which utilize soluble carbohydrates as an energy source. The relative abundance of acetate-producing bacterium Acetobacter decreased during heat stress. We concluded that heat stress is associated with changes in ruminal bacterial composition and metabolites, with more lactate and less acetate-producing species in the population, which potentially negatively affects milk production.

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Effect of dietary net energy concentration on dry matter intake and energy partition in cows in mid-lactation under heat stress

Animal Science Journal ◽

10.1111/asj.12561 ◽

2016 ◽

Vol 87 (11) ◽

pp. 1352-1362 ◽

Cited By ~ 3

Author(s):

Fangquan Yan ◽

Bai Xue ◽

Liangrong Song ◽

Jun Xiao ◽

Siyan Ding ◽

...

Keyword(s):

Heat Stress ◽

Dry Matter ◽

Dry Matter Intake ◽

Energy Concentration ◽

Net Energy ◽

Energy Partition

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Feeding systems and productive and physiological parameters of lambs raised under heat stress

The Journal of Agriculture of the University of Puerto Rico ◽

10.46429/jaupr.v104i2.19041 ◽

2021 ◽

pp. 181-199

Author(s):

Abner A. Rodríguez-Carías ◽

José Israel Suárez-Rodríguez ◽

Jonathan Collazo ◽

John Fernández-Van Cleve

Keyword(s):

Heart Rate ◽

Heat Stress ◽

Respiratory Rate ◽

Rectal Temperature ◽

Dry Matter ◽

Physiological Parameters ◽

Stress Conditions ◽

Initial Weight ◽

Rotational Grazing ◽

Grazing System

The objective of this study was to determine physiological parameters (rectal temperature = RT, respiratory rate = RR, heart rate = HR) and production parameters (dry matter intake = DMI, water intake = WI, average daily weight gain = ADG, and feed conversion = FC) of crossbred and Katahdin lambs raised in rotational grazing of native pastures (NP) and in confinement under heat stress conditions. Nine crossbred lambs (average initial weight = 19.4 kg) were used and fed in a rotational grazing system for 70 days with occupation and rest periods of seven and 21 days, respectively. The lambs had daily access to the grazing area for four to six hours, grass hay and water ad libitum, a daily supplement of 100 g of commercial concentrate and a nutritional block. In the confined system, six lambs of the Katahdin breed (average initial weight = 27.3 kg) were used, and for 28 days these were fed total mixed rations (TMR) containing 30% grass hay, 15.4% soybean meal, 54.6% corn grain and a mineral block. The diet contained 14% Crude Protein (CP) and 66% Total Digestible Nutrients (TDN) and was formulated for an ADG of 200 g. The offered and rejected feed was quantified every day [4% body weight (BW)/dry matter basis (DMB)] to determine the DMI, and the volume of water offered and rejected to determine WI. To validate the stress conditions, the maximum environmental temperature and relative humidity were monitored to calculate the temperature and humidity index (THI), and the RT, HR and RR of the 15 lambs were determined. The lambs were weighed every seven days. In both experiments, the THI oscillated between 78 and 80. The lambs were under environmental heat stress conditions (THI x̅ = 79) during both studies. The averages of HR and RT in the grazing system were 118.0 beats per minute and 38.6° C, while the averages under the confinement system were 108.6 beats per minute and 39.4° C, respectively. The average RR (53.6 and 62.6 breaths per minute, in grazing and in confinement, respectively) was greater than the normal value considered for thermal comfort. Respiratory rate is the main mechanism used by lambs to dissipate heat. The heart rate also showed slightly higher values than those reported for animals in their comfort zone. However, the rectal temperature values were constant. As expected, crossbred lambs fed under grazing conditions with naturalized pastures (NP) had a low ADG (55.6 g). Nevertheless, Katahdin lambs fed in confinement with TMR had a DMI of 935.4 g/day (3.14% BW/DMB), a WI of 3.5 L/day, a FC of 4.74 and an ADG of 226.2 g. In conclusion, raising crossbred sheep in rotational grazing of NP without any type of agronomic management results in ADG that could not be considered viable in traditional production systems. The introduction of pure breeds and feeding them in confined systems with a TMR results in a pre-determined ADG (>200 g/day) and is an alternative that can be evaluated economically for its practical implementation.

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