scholarly journals Avoidance of phenylthiocarbamide in mature Targhee and Rambouillet rams

2019 ◽  
Vol 3 (4) ◽  
pp. 1194-1204
Author(s):  
Dillan Henslee ◽  
Joel Yelich ◽  
J Bret Taylor ◽  
Melinda Ellison

Abstract Shrub encroachment on grasslands is a worldwide issue and sheep are a potential tool for mitigating shrub encroachment. Many shrubs, however, contain bitter-tasting compounds that may deter grazers. Cattle and sheep commonly graze rangelands, but of the two, sheep have a greater tolerance for bitter compounds and would be expected to consume more bitter-tasting vegetation. We hypothesized that sheep could detect (i.e., taste) bitter-tasting compounds and the sensitivity to these compounds would vary from animal to animal. The objective of this study was to determine whether sheep could detect the bitter-tasting compound phenylthiocarbamide (PTC), and if so, what PTC concentration would elicit an avoidance response. Using a crossover study design, mature Rambouillet and Targhee rams (n = 30) were subjected in randomized order to various PTC concentrations mixed in the drinking water (PTC solution). In trials 1 and 2 (n = 15/trial), 0.20, 0.56, 1.57, 4.39, and 12.29 mM and 0.20, 0.43, 0.94, 2.03, and 4.39 mM of PTC were tested, respectively. On test days, PTC solution (trial 1: 1.5 kg; trial 2: 3.0 kg) and water (same amounts) were offered for ad libitum intake in a side-by-side presentation for 1 h in trial 1 and 2 h in trial 2. Each test day was followed by a rest day where PTC solution was replaced with water to limit potential carry over effects into the next test day. Consumption of PTC solution for each PTC concentration was expressed as the percentage of PTC solution intake of total morning fluid intake. There was no effect (P > 0.74) of sequence that rams received PTC solutions on PTC consumption during either trial. As PTC concentration increased, percentage of PTC solution intake decreased (P ≤ 0.01) for both trials. The greatest decrease in percentage of PTC solution intake occurred between 1.57 and 4.39 mM (58%) for trial 1 and 2.03 and 4.39 mM (72%) for trial 2. In trial 2, the least percentage of PTC solution intake was the 4.39 mM PTC concentration, which was different (P ≤ 0.05) from lesser PTC concentrations. All other PTC concentrations did not differ (P > 0.05) from each other in percentage intake. This research suggests rams could taste the PTC, and the concentration at which PTC solution was avoided varied across rams. It may be possible to select sheep, based on demonstrated avoidance of PTC, for targeted grazing applications to manipulate vegetation toward range management goals.

1983 ◽  
Vol 245 (1) ◽  
pp. F48-F57
Author(s):  
H. T. Campbell ◽  
P. A. Craven ◽  
F. R. DeRubertis

The effects of fluid intake on basal and vasopressin-responsive urinary PGE excretion (UPGEV) were examined in conscious rats under conditions of 1) ad libitum water intake, 2) water deprivation, and 3) water diuresis induced by ad libitum intake of 5% dextrose in water. UPGEV fell progressively during 40 h of water deprivation. Water diuresis after water deprivation increased UPGEV transiently (8 h). Vasopressin (Pitressin tannate in oil, 5 U/kg subcutaneously) increased UPGEV and decreased urine volume (V) in rats on ad libitum water intake but did not alter UPGEV during water deprivation. Indomethacin suppressed UPGEV (70-90%), increased basal urine osmolality (Uosmol), and potentiated the antidiuretic response to Pitressin in rats on ad libitum water intake. Indomethacin accelerated by 8 h the onset of maximal antidiuresis in water-deprived rats but did not significantly alter water balance. During water diuresis, UPGEV declined in the first 8 h after Pitressin. Thereafter, UPGEV increased markedly, concurrent with early vasopressin escape. Indomethacin or meclofenamate inhibited the rise in UPGEV, the decline in Uosmol, and the increase in V of the escape phase. Indomethacin or meclofenamate also impaired the excretion of an acute water load (5% body wt) given during escape. The spontaneous decline in UPGEV during hydropenia may serve to maximize physiologic antidiuresis. Conversely, the marked increase in UPGEV induced by administration of vasopressin during water diuresis may serve to suppress the antidiuretic response and thus play a role in the mediation of escape from physiologically inappropriate antidiuresis.


2002 ◽  
Vol 80 (3) ◽  
pp. 812-817 ◽  
Author(s):  
G. N. Hermesmeyer ◽  
L. L. Berger ◽  
N. R. Merchen ◽  
T. G. Nash

1984 ◽  
Vol 67 (4) ◽  
pp. 413-420 ◽  
Author(s):  
Sming Kaojarern ◽  
Polavat Chennavasin ◽  
Ann Burdette ◽  
William B. Campbell ◽  
D. Craig Brater

1. Eight normal subjects underwent water loading alone and water loading plus 40 mg of frusemide IV, fluid intake ad libitum alone and fluid intake ad libitum plus frusemide, plus each of the preceding after pretreatment with indomethacin. 2. After frusemide administration, increases in urinary sodium excretion paralleled increases in urinary volume, and urinary prostaglandin E2 (PGE2) excretion correlated closely with sodium excretion (y = 1.03x −0.28; r = 0.940; P<.0001). 3. In the absence of the diuretic, urinary volume varied over a wide range with little change in sodium excretion. Again, urinary PGE2 excretion correlated with urinary sodium excretion (y = 0.12x + 0.05; r = 0.789; P<.002). However, the correlation differed markedly from that observed in the studies with frusemide. 4. Expressing urinary PGE2 excretion as a function of urinary volume for all of the studies resulted in a highly significant correlation (y = 10.7x −0.70; r = 0.975; P<.0001). 5. Multiple and stepwise regression analyses assessing the correlation of urinary PGE2 excretion with urinary flow rate and with indices of function of various nephron segments indicate that the correlation with urinary PGE2 could be predominantly accounted for by urinary volume. 6. We conclude that in the condition of this study in man, urinary PGE2 excretion is a correlate of urinary volume.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 94-95
Author(s):  
Kelsie Webb ◽  
Ronald J Trotta ◽  
Phillip Bridges ◽  
James Matthews

Abstract To test the hypothesis that average daily gain (ADG) and clinical parameters of steers grazing novel non-toxic (NTE) or toxic KY-31 (TE) endophyte-infected tall fescue would be improved by ad libitum intake of vitamin-mineral mixes (V-M) that contain 27 ppm Se as a 1:1 blend of SELPLEX:sodium selenite (MIX) vs sodium selenite (ISe), 32 TE-naïve beef steers depleted of Se were randomly assigned to ad libitum consumption ISe vs MIX for 35 d and fed enough of a NTE/alfalfa/grain diet to achieve 0.57 kg BW gain/d. Within Se-form treatments, 2 steers were randomly assigned to each of 4, 2-acre NTE (ISe = 316 ± 31 kg, MIX = 315 ± 22 kg) or TE (ISe = 316 ± 37 kg, MIX = 314 ± 39 kg) paddocks for 84 d and had ad libitum access to their respective V-M. The MIXED procedure of SAS was used to assess effects of day, Se-form (ISe, MIX) and endophyte (NTE, TE) treatments, and their interactions. Whole blood Se decreased (P &lt; 0.01) 31% from d 0 to 84 and was 6.2% greater (P &lt; 0.01) for MIX steers. Serum prolactin decreased (P &lt; 0.01) 18% for NTE and 48% for TE steers from d 0 to 84 and was 17% greater (P = 0.01) for MIX vs. ISe TE steers. Alkaline phosphatase activity (AP) decreased (P &lt; 0.02) 27% from d 0 to 84 and was 15% greater (P &lt; 0.02) for MIX steers. Serum urea nitrogen increased (P &lt; 0.02) 8.2% from d 0 to 84 for TE but not NTE steers. Average daily gain (kg/d) was less (P &lt; 0.01) in TE (-0.18) vs NTE (0.09) steers. We conclude that the ad libitum intake of MIX ameliorated the negative effects of consuming TE on serum prolactin and AP but not ADG.


2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Fiastuti Witjaksono ◽  
Widjaja Lukito ◽  
Andi Wijaya ◽  
Nagita Gianty Annisa ◽  
Joan Jutamulia ◽  
...  

1985 ◽  
Vol 36 (3) ◽  
pp. 483 ◽  
Author(s):  
JK Egan ◽  
PT Doyle

Six mature Merino sheep received three treatments in a randomized block design experiment. The treatments were: chopped oaten hay diet at 90% of ad libitum intake without urea (L); the ciet offered at the same level as for L with urea infused into the rumen at 11.5 g kg-1 dry matter intake (LU); and the diet offered at 90% of the ad libitum intake achieved with urea infused at 11.5 g kg-1 dry matter intake (HU). Sheep given HU consumed 37% more (P < 0.01) organic matter (OM) than those fed L or LU, but the apparent digestibility of OM did not vary (59.2-61.8%) between treatments. The addit onal food consumption was associated with c. 20% increase (P < 0.05) in the weight of OM in the reticulorumen and significantly higher (by 10-35%; P < 0.05) fractional outflow rates of most dietary and microbial constituents of digesta. The fractional digestion rate of potentially digestible plant cell walls was not affected by urea, but the flow of microbial non-ammonia nitrogen from the abomasum was enhanced (L, 7.0; LU, 8.2; HU, 12.5 g day-1; P < 0.05). The results of this study suggest that the stimulatory effect of urea upon food intake was associated with the provision of additional microbial protein for digestion in the intestines, rather than changes in the rate or extent of organic matter fermentation in the reticulorumen.


Endocrinology ◽  
2007 ◽  
Vol 148 (10) ◽  
pp. 4623-4633 ◽  
Author(s):  
Ruth B. S. Harris ◽  
Timothy J. Bartness ◽  
Harvey J. Grill

Peripheral infusions of physiological doses of leptin decrease body fat mass, but it is not known whether this results from direct effects on peripheral tissue or activation of central leptin receptors. In this study, we infused chronically decerebrate (CD) rats, in which the forebrain was surgically isolated from the caudal brainstem, with 60 μg leptin/d or PBS for 14 d from ip mini-osmotic pumps. The CD rats were tube fed an amount of food equivalent to the intake of ad libitum-fed intact controls or 75% of this amount to account for their reduced energy expenditure. Control rats fed ad libitum or tube fed 75, 100, or 125% of their ad libitum intake also were peripherally infused with leptin or PBS. CD rats had a lower serum testosterone, energy expenditure, and lean body mass compared with controls but had increased levels of adiponectin and leptin and were obese. Leptin increased body fat and decreased energy expenditure during the light period in 100%-fed CD rats, but not 75%-fed CD rats. Leptin decreased body fat of ad libitum- and 100%-fed but not 75%-fed or 125%-fed intact controls. Energy expenditure did not change in any control group. These results show that leptin can change body fat independent of a change in food intake or energy expenditure, that the forebrain normally prevents leptin from inhibiting energy expenditure through mechanisms initiated in the caudal brainstem or peripheral tissues, and that the leptin response in both intact and CD rats is determined by the energy status of the animal.


2008 ◽  
Vol 15 (3) ◽  
pp. 235 ◽  
Author(s):  
P. PURSIAINEN ◽  
M. TUORI

The effect of replacing wilted grass silage (GS) with pea-barley intercrop silage (PBS) on feed intake, diet digestibility and milk production was studied with 8 multiparous Ayrshire-cows in a replicated 4 × 4 Latin square experiment. Proportion of PBS was 0 (PBS0), 33 (PBS33), 67 (PBS67) or 100 (PBS100) % of silage dry matter (DM). The DM content was 559 and 255 g kg-1 for GS and PBS. Crude protein content was 131 and 170 g kg-1 DM, respectively. Pea-barley silage was more extensively fermented than GS with total fermentation acid content of 120 vs. 12 g kg-1 DM. Silage was fed for ad libitum intake and supplemented with on the average 13 kg concentrate per day. Silage DM intake was 9.2 (PBS0), 9.7 (PBS33), 9.0 (PBS67) and 7.1 (PBS100) kg per day (Pquadr. < 0.05). The energy corrected milk yield [30.3 (PBS0), 29.8 (PBS33), 30.3 (PBS67), 31.3 (PBS100) kg per day] was not significantly affected by the treatment. Milk protein concentration decreased linearly (P < 0.05) in response to feeding PBS. It is concluded that PBS can replace up to two thirds of wilted, moderate quality GS in the feeding of dairy cows because in this experiment pure pea-barley silage reduced silage intake.


2015 ◽  
Vol 63 (1) ◽  
pp. 12 ◽  
Author(s):  
Alexandra M. Leslie ◽  
Mathew Stewart ◽  
Elizabeth Price ◽  
Adam J. Munn

Daily torpor, a short-term reduction in body temperature and metabolism, is an energy-saving strategy that has been interpreted as an adaptation to unpredictable resource availability. However, the effect of food-supply variability on torpor, separately from consistent food restriction, remains largely unexamined. In this study, we investigated the effect of unpredictable food availability on torpor in stripe-faced dunnarts (Sminthopsis macroura). After a control period of ad libitum feeding, dunnarts were offered 65% of their average daily ad libitum intake over 31 days, either as a constant restriction (i.e. as equal amount of food offered each day) or as an unpredictable schedule of feed offered, varied daily as 0%, 30%, 60%, 100% or 130% of ad libitum. Both feeding groups had increased torpor-bout occurrences (as a proportion of all dunnarts on a given day) and torpor-bout frequency (average number of bouts each day) when on a restricted diet compared with ad libitum feeding, but torpor frequency did not differ between the consistently restricted and unpredictably restricted groups. Most importantly, torpor occurrence and daily bout frequency by the unpredictably restricted group appeared to change in direct association with the amount of food offered on each day; torpor frequency was higher on days of low food availability. Our data do not support the interpretation that torpor is a response to unpredictable food availability per se, but rather that torpor allowed a rapid adjustment of energy expenditure to manage daily fluctuations in food availability.


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