Feed intake component of fescue toxicosis during short-term exposure to thermoneutral and heat stress conditions

2008 ◽  
Author(s):  
Prakash Babu Bommala
1998 ◽  
Vol 66 (2) ◽  
pp. 431-440 ◽  
Author(s):  
A.-H. Tauson ◽  
A. Chwalibog ◽  
J. Ludvigsen ◽  
K. Jakobsen ◽  
G. Thorbek

AbstractThe effects of short-term exposure to high ambient temperatures on gas exchange, heat production (HE), respiration rate (RR) and rectal temperature were evaluated individually with boars of approximately 100 kg live weight. The boars were of different breeds with four of Yorkshire (YS), eight of Danish Landrace (DL), out of which three were found stress susceptible by the halothane test (DLH+), eight of Duroc (DR) and eight of Hampshire (HS) breeds. After 1 h rest in the respiration chamber at 17·0°C the gas exchange measurements started with al-h basal period at 17 °C, followed by 2h of heating during which temperature increased to 35·0 °C (period I) and then further to 39·7X1 (period II). Then cooling of the chamber started, and after 1 h (period III) temperature had decreased to 21·8°C, and after the 2nd h of cooling (period IV) temperature was 18·2 °C. The gas exchange was measured for each hour from 09.00 h (basal period) until 14.00 h (period IV). RR was recorded every 15 min. Rectal temperatures were measured when the animals were removed from the chamber. The gas exchange and HE increased slowly during period I but rapidly in period II, followed by decreasing values in the cooling periods. HS and DLH+ had considerably higher gas exchange and HE than other breeds in these two periods and the values remained high during period III. In period IV all breeds had gas exchange rates and HE below those of the basal period. RR increased slightly in period I and then a sharp increase followed during period II. Maximum RR was recorded in period III with an average of 183 breaths per min for all breeds. RR increased earlier and more steeply in HS and reached the highest mean value of 236 breaths per min. Four HS boars salivated heavily during heat stress and rectal temperatures of these animals were 39·7 °C when removed from the chamber compared with close to 39·0 °C for all other breeds. It was concluded that there were considerable breed differences in response to heat stress and that DLH+ and HS were more severely stressed than boars ofYS, DL and DR.


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 392-392
Author(s):  
Eduardo Colombo ◽  
Reinaldo F Cooke ◽  
Kelsey Schubach ◽  
Bruna Rett ◽  
Alice Brandão

Abstract This experiment compared physiological and productive parameters in finishing cattle managed under heat stress conditions, and supplemented or not with Omnigen-AF (Phibro Animal Health, Teaneck, NJ). Crossbred cattle (Bos taurus × B. indicus; 64 heifers and 64 steers) were ranked by initial body weight (BW; 440 ± 3 kg) and sex, and allocated to 1 of 16 pens (8 heifers or steers/pen). Pens within sex were randomly assigned to receive (OMN; n = 8) or not (CON; n = 8) Omnigen-AF at 56 g/cow daily (as-fed basis). Cattle received a total-mixed ration during the experimental period (d 0 to 107), and Omnigen-AF was offered daily as a top-dress to OMN. Cattle were shipped on d 107 to a commercial packing facility for slaughter. Cattle BW was recorded and samples of blood and tail-switch hair collected on d 0, 28, 56, 84, and 106. Feed intake was evaluated biweekly from each pen, and feed efficiency calculated according to total feed intake and BW gain of each pen. From d 0 to 7, 28 to 42, and 84 to 98, heifer intravaginal temperature was recorded hourly (iButton temperature loggers DS1922L, Maxim Integrated, San Jose, CA). Environmental temperature humidity index (THI) was also recorded hourly throughout the experiment, and averaged 79.8 ± 0.6. Heifers receiving OMN had less (P < 0.05) vaginal temperature from 1500 to 1900h (39.05 vs. 39.19 °C), when THI ranged from 85.3 to 90.1. No treatment effects were detected (P > 0.20) for BW gain, feed intake, feed efficiency, and carcass traits. No treatment effects were also detected (P > 0.17) for plasma concentrations of cortisol and haptoglobin, and cortisol concentrations in tail-switch hair. Hence, OMN ameliorated hyperthermia in finishing cattle exposed to heat stress conditions, but such benefit was not sufficient to improve productive and physiological responses.


2017 ◽  
Vol 57 (3) ◽  
pp. 569 ◽  
Author(s):  
F. Moslemipur ◽  
S. Golzar-Adabi

Shearing is a common practice for lamb hygiene and health, which can also influence the animal survival and productivity in stressful environments. This study was conducted to investigate the effects of shearing on performance and some metabolic and physiological parameters of fattening lambs exposed to ambient heat stress. Thirty -two male Dalagh fattening lambs (32.4 ± 5.7 kg), 3.5 ± 0.5 months of age, were selected from a herd existing at the research station of the University of Gonbad Kavoos (temperate mild-latitude zone of Iran). Lambs were divided into two groups, maintained individually and fed with a mixture of alfalfa hay and concentrate with free access to drinking water. One group was completely shorn while the other group was left unshorn, and both groups were reared for 10 weeks (July–Sept.) with mean ambient temperature of 29.3°C. Feed intake and liveweight changes were recorded weekly whereas metabolic parameters were measured daily. Fasting blood samples were collected three times a week and used for blood metabolites and hormone assays. Results showed that shearing has no effects on feed intake and weight gain over the study. Feed conversion ratio was improved (P < 0.05) by shearing (10.70 vs 13.26 kg/kg). Shearing also caused a decline in lamb rectal temperature (P < 0.05), whereas heart rate remained unchanged. Respiratory rate was lower in shorn lambs (P < 0.001), whereas blood glucose, urea and total protein levels were not affected. Serum concentrations of thyroxine declined in shorn lambs compared with unshorn lambs (P < 0.05), but cortisol level was unchanged between groups. In conclusion, the study showed that when lambs are kept sheltered under heat stress conditions, shearing appears to induce energy retention via reducing some vital activities such as respiration and heat loss leading to enhanced feed efficiency. The decrease in thyroxine level can be considered as the possible underlying mechanism for the decline observed in rectal temperature.


2014 ◽  
Vol 92 (12) ◽  
pp. 5444-5454 ◽  
Author(s):  
S. C. Pearce ◽  
M. V. Sanz-Fernandez ◽  
J. H. Hollis ◽  
L. H. Baumgard ◽  
N. K. Gabler

Animals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 359 ◽  
Author(s):  
Wei Fang ◽  
Xiaobin Wen ◽  
Qingshi Meng ◽  
Lei Liu ◽  
Jingjing Xie ◽  
...  

Heat stress influences lipid metabolism independently of nutrient intake. It is not well understood how cholesterol and bile acid (BA) metabolism are affected by heat stress. To investigate the alterations of cholesterol and bile acids when pigs are exposed to short term heat stress, 24 Large White pigs (63.2 ± 9.5 kg body weight, BW) were distributed into one of three environmental treatments: control conditions (CON, 23 °C with ad libitum intake; n = 8), heat stress conditions (HS, 33 °C with ad libitum intake; n = 8), or pair-fed conditions (PF, 23 °C with the same amount to the feed consumed by the HS; n = 8) for three days. Compared with CON pigs, HS pigs reduced the average daily feed intake and average daily gain by 55% and 124%, respectively, and significantly increased rectal temperatures by 0.9 °C and respiration rates more than three-fold. The serum total cholesterol (TC), low-density lipoprotein-cholesterol, and triglycerides (TG) increased (p < 0.05), while hepatic TC, TG, and mRNA of 3-hydroxy-3-methylglutaryl-CoA reductase were reduced on day 3. Furthermore, liver taurine-conjugated BAs (TCBAs), including taurolithocholic acid, taurochenodeoxycholic acid (TCDCA), tauroursodeoxycholic acid, taurohyodeoxycholic acid, and taurocholic acid were elevated in HS pigs compared to CON and PF pigs (p < 0.05), and the level of chenodeoxycholic acid was more significant in the PF group than in the CON and HS groups. The concentration of ursodeoxycholic acid in the serum was higher in HS pigs than CON and PF pigs (p < 0.05), and TCDCA was increased in HS pigs compared with PF pigs (p < 0.05). Altogether, short-term HS reduced hepatic cholesterol levels by decreasing cholesterol synthesis, promoting cholesterol to TCBAs conversion, and cholesterol release to serum in growing pigs. This independently reduced feed intake might serve as a mechanism to protect cells from damage during the early period.


2018 ◽  
Vol 76 ◽  
pp. 1-7 ◽  
Author(s):  
M. Cervantes ◽  
D. Antoine ◽  
J.A. Valle ◽  
N. Vásquez ◽  
R.L. Camacho ◽  
...  

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