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

2004 ◽  
Vol 55 (3) ◽  
pp. 253 ◽  
Author(s):  
John B. Gaughan ◽  
M. Shane Davis ◽  
Terry L. Mader

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.

2021 ◽  
Vol 2 ◽  
Author(s):  
Véronique Ouellet ◽  
Izabella M. Toledo ◽  
Bethany Dado-Senn ◽  
Geoffrey E. Dahl ◽  
Jimena Laporta

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 &lt; 0.001) and respiration rate (+23 breaths/min; P &lt; 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.


2020 ◽  
Vol 44 (4) ◽  
pp. 101-109
Author(s):  
A. A. Adeyemi ◽  
O. A. Olorunnisomo

High ambient temperature and relative humidity exert a negative effect on the performance of both Bostaurus and Bosindicus cattle in Nigeria. The use of water sprinklers to shower cattle may have the ability to mitigate the effect of heat stress. In this study, cold drinking water (10 C 15 C) and ordinary drinking water (20 C -25 C) were offered to six Jersey and six Sokoto Gudali heifers to compare the effect on heat stress. They were divided into two treatments each. Each treatment had three replicates and cattle were assigned in a completely randomised design to the treatment. Rectal temperature, respiratory rate, dry matter intake, daily weight gain and percentage body weight were measured. At three months of administration of treatment, mean morning and afternoon RT varied from 37.94C to39.17 C for Sokoto Gudali and 37.97 C to 39.21 C for Jersey heifers, RR varied from 20.54 bpm to 30.73 bpm for Gudali and 32.17 bpm to 42.63 bpm for Jersey heifers. There were significant (P<0.05) differences in respiratory rate, rectal temperature and dry matter intake between both the zebu and exotic heifers given ordinary water and those given cold water when treatments were administered. Mean RT was 38.99 C and 38.14 C for Gudali and 38.98 C and 38.34 C for Jersey heifers while mean RR was 28.12 bpm and 23.11 bpm for Gudali and 39.89 and 33.78 bpm for Jersey heifers. DMI were 4.14 kg/d and 6.01 kg/d, daily weight gain were 0.27 kg/d and 0.50 kg/d and FCR were 15.33 and 12.02. Cold drinking water is an effective method of ameliorating heat stress in zebu and Jersey breeds of cattle.  


2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4565 ◽  
Author(s):  
Ériton Egidio Lisboa Valente ◽  
Mario Luiz Chizzotti ◽  
Cristiane Viol Ribeiro de Oliveira ◽  
Matheus Castilho Galvão ◽  
Silas Sebastião Domingues ◽  
...  

<p>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 (<em>B. indicus</em>) and Angus (<em>B. taurus</em>) 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&gt;0.05) by heat stress. However, Angus bulls decreased diurnal DMI by 24% and daily DMI decreased (P&lt;0.05) by 15% on HHS. In TN Angus bulls had higher (P&lt;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&gt;0.05) daily DMI (31.6 and 30.2 g/kg of BW, respectively). We observed an increase (P&lt;0.05) in respiratory frequency, but water intake was not affected (P&gt;0.05) by heat stress. The heart rate decreased (P&lt;0.05) with heat stress. No differences were found (P&gt;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. </p>


Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 925
Author(s):  
Zhao ◽  
Min ◽  
Zheng ◽  
Wang

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.


1971 ◽  
Vol 26 (3) ◽  
pp. 363-381 ◽  
Author(s):  
J. H. B. Roy ◽  
I. J. F. Stobo ◽  
Helen J. Gaston ◽  
P. Ganderton ◽  
Susan M. Shotton ◽  
...  

1. Eighty bull calves, comprising forty-eight ayrshire and sixteen each of the Friesian and Jersey breeds, were used in a randomized block experiment. Forty calves were maintainted at a mean environmental temperature of 21° and forty at 14·5°. Within each temperature, twenty calves were reared from birth on a liquid milk substitute diet (pre-ruminant calves) and twenty were weaned at 35 d of age on to dry food (ruminant calves). Each type of diet was gien either ad lib. or at a restricted level. The calves were slaughtered at about 100 d of age.2. The incidence of a high rectal temperature (> 39·39°) was greater for the pre-ruminant than for the ruminant calves during the first 14 d of life and throughout the whole experimental period, and was higher for calves at an enviromental temperature of 21° than for thosekept at 14·5°. During the experimental period as a whole, but not during the first 14 d of life, the incidence of diarrhoea was greater for the pre-ruminant calves. Mean rectal temperature was higher for the pre-ruminant calves and also higher for the calves reared at the high environmental temperature.3. The incidence of lung lesions at slaughter was significantly higher in the ruminant than in the pre-ruminant calves, and tended to be higher at the high environmental temperature. There was a highly significant positive relationship between severity of lung lesions and incidence of a high rectal temperature (> 39·33°) and mean rectal temperature. Jersey and Friesian calves, but not Ayrshire calves, showed increased severity of lung lesions with increasing relative humidity at the low environmental temperature. When the results at the 'high' environmentaltemperature were combined with those obtained in an earlier experiment, the severity of lung lesiogs for Jersey and Friesian calves increased with decreasing relative humidity. At the ‘high’ but not at the ‘low’ temperature, severity of lung lesions was inversely related to skin weight/kgO·73.4. Live-weight gain was much lower for the ruminant calves, but was unaffected by environ-mental temperature. Daily dry-matter intake from liquid diets given ad lib. did not differ be-tween breeds at the same live weight. In contrast, daily dry-matter intake from dry food given ad lib. was greatest for the Jersey and lowest for the Friesian at the same live weight. The same daily dry-matter intake from liquid as from dry diets was achieved at similar percentages of mature weight for the three breeds. Relative weight gain within type of diet was similar for Jersey and Ayrshire calves, but tended to be higher for the Friesian calves.5. Carcassweight, carcass weight0·73, perirenal fat deposition, skin weight and killing out percentage were much lower for the ruminant calves. When adjusted for differences between treatment means for carcass weight0·73, perirenal fat deposition was greater at the ad lib. levels of intake and was 36% greater for pre-ruminant calves given milk substitute ad lib. at an environmental temperature of 21° than for those maintained at 14·5°.6. It is concluded that there is no advantage to be gained from rearing calves at an environ mental temperature above 14·5°, unless increased fat deposition is required in veal calves.


2016 ◽  
Vol 87 (11) ◽  
pp. 1352-1362 ◽  
Author(s):  
Fangquan Yan ◽  
Bai Xue ◽  
Liangrong Song ◽  
Jun Xiao ◽  
Siyan Ding ◽  
...  

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 266-266
Author(s):  
Pablo C Grijalva ◽  
Rachel Reith ◽  
Renae L Sieck ◽  
Rebecca Swanson ◽  
Ty B Schmidt ◽  
...  

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 &lt; 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 = &gt;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.


Author(s):  
Abner A. Rodríguez-Carías ◽  
José Israel Suárez-Rodríguez ◽  
Jonathan Collazo ◽  
John Fernández-Van Cleve

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.


1997 ◽  
Vol 272 (1) ◽  
pp. R226-R233 ◽  
Author(s):  
A. S. Weller ◽  
C. E. Millard ◽  
M. A. Stroud ◽  
P. L. Greenhaff ◽  
I. A. Macdonald

The potentially deleterious influence of body cooling on the thermoregulatory and metabolic responses to prolonged walking exercise has not been established. To address this problem, 10 men completed a 6-h intermittent (15 min rest, 45 min exercise) walking protocol in a thermoneutral (+15 degrees C) condition (Neutral) and a cold (+5 degrees C), wet, and windy condition (Cold). The first two exercise periods were conducted at a higher intensity (Higher, 6 km/h and 10% incline) than the subsequent four exercise periods (Lower, 5 km/h and 0% incline). Rectal temperature was lower and heart rate no different in Cold compared with Neutral, whereas the following were higher: oxygen consumption, respiratory exchange ratio, plasma norepinephrine and epinephrine, and blood lactate and glucose. There was no environmental influence on these variables during Higher. In conclusion, heat production during Lower was not sufficient to offset heat loss to the cold environment, and the resulting reduction in rectal temperature and metabolic perturbations may be detrimental if exercise is prolonged.


1981 ◽  
Vol 29 (6) ◽  
pp. 875 ◽  
Author(s):  
DJ Kitchener

Individual adult quokkas in the field were studied in relation to their choice of shelter sites on hot summer days and to their physiological response to heat stress and physical condition. Metabolic rate, evaporative water loss and rectal temperature were measured under laboratory conditions. The extent to which male quokkas moved to better shelter on hot days is significantly and positively correlated with their metabolic rate at T*a 37�C; movement of females is significantly but negatively correlated with their rectal temperature. It is concluded that individual quokkas moving more frequently to better shelter on hot days (males) were physiologically less able to tolerate heat stress. Indices of physical condition and indicators of health and age were not correlated with movement. It is suggested that physiological variation in quokkas, both between and within sexes, effectively reduces intraspecific competition for a limiting resource (shelter). This expands their realised niche, increasing the carrying capacity of their environment.


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