Physiology Commons^™

Kisspeptin Receptor Agonist (Ftm080) Increased Plasma Concentrations Of Luteinizing Hormone In Anestrous Ewes, Brian K. Whitlock, Kelly A. Chameroy, Rebecca R. Payton, Shinya Oishi, Nobutaka Fujii, Joseph A. Daniel

Brian K Whitlock, PhD, DVM, DACT

Kisspeptin (KP) and the KP receptor (Kiss1r) are integral to central regulation of the gonadotropic-axis. The demonstration that intravenous infusion of KP can stimulate gonadotropin secretion and ovulation in seasonally anestrous female sheep offers a means of manipulating the reproductive axis. However, KP may be of limited clinical use because of the short circulating half-life. Kiss1r agonists with increased half-life and similar efficacy to KP in vitro potentially may provide beneficial applications in breeding management of many species. However, many of these agonists have not been tested in vivo. This study was designed to test and compare the effects of …

Effect Of Meloxicam On Gain And Inflammatory Response Of Calves Castrated By Banding Post-Weaning, Brian K. Whitlock, Peter D. Krawczel, Jeff A. Carroll, Nicole C. Burdick Sanchez, Jeff W. Dailey, Joseph A. Daniel, Johann F. Coetzee

Brian K Whitlock, PhD, DVM, DACT

Castration may detrimentally affect the health and performance of weaned calves, and painful procedures are increasingly becoming a public concern. The objective of this study was to determine the effects of castration (by banding) with or without administration of meloxicam, a non-steroid anti-inflammatory, on performance and inflammatory response in weaned beef calves. Forty-eight (weaned) beef calves [10.0±0.2 mo old; 304±6 kg BW] were blocked by age, BW, wither height, scrotal circumference, and source, then randomly assigned to 1 of 3 treatments (n=16 calves per treatment: 1) intact bulls (BULL), 2) castration by banding (BAN), or 3) castration by banding with …

Effect Of Meloxicam On Gain And Behavior Of Calves Castrated By Banding Pre-Weaning, Joseph A. Daniel, Peter D. Krawczel, Brian K. Whitlock

Brian K Whitlock, PhD, DVM, DACT

The objective was to determine if oral meloxicam (M; a non-steroid anti-inflammatory) administered at castration of pre-weaning calves affected ADG or behavior. Prior to castration (14 d), Angus bulls were assigned to bull (BULL; n = 7; age 106 ± 6 d; BW = 174.2 ±7.7 kg; scrotal circumference 17.7 ± 0.4 cm), castrated (BAN; n = 12; age = 105 ± 5 d; BW = 144.5 ± 7.6 kg; scrotal circumference = 16 ± 0.4 cm) or castrated with meloxicam (BAN+M; n = 13; age = 121 ± 6 d; BW = 145.8 ± 6 kg; scrotal circumference = …

Meloxicam Mediates Short-Term Behavioral Changes Of Castrated Calves, Peter D. Krawczel, Jeff A. Carroll, Nicole C. Burdick Sanchez, Jeff W. Dailey, Joseph A. Daniel, Johann F. Coetzee, Brian K. Whitlock

Brian K Whitlock, PhD, DVM, DACT

Castration may detrimentally affect the health and performance of weaned calves and painful procedures are increasingly a public concern. Therefore, practical pain mitigation is critical. The objective was to determine the effects of castration (by banding) with or without administration of NSAID, meloxicam, on the behavior of weaned beef calves. Forty-eight (56 d post-weaning) beef calves [10.0 ± 0.2 (mean ± SE) mo old; 304 ± 6 kg BW] were blocked by multiple factors then randomly assigned to 3 treatments (n = 16 calves per treatment: 1) intact bulls (BULL), 2) castration by banding (BAN), or 3) castration by banding …

Heifer Estrous Cycle Stage Impacts Luteinizing And Growth Hormone Response To Kisspeptin, Brian K. Whitlock, Joseph A. Daniel, Robyn R. Wilborn, Barbara P. Steele, James L. Sartin

Brian K Whitlock, PhD, DVM, DACT

The reproductive neuropeptide, kisspeptin (KP), may have a role in regulation of growth hormone (GH) secretion. Expression of KP and its receptor (Kiss1r) are developmentally and hormonally regulated. This study was conducted to determine the effects of KP on plasma concentrations of luteinizing hormone (LH) and GH in pubertal heifers during different functional reproductive stages. Heifers received a single injection of KP (100 pmole / kg) or saline intravenously during proestrus, estrus, and diestrus, and serial blood samples were collected for 3 hours to determine the response of both LH and GH after treatment. Mean concentrations of LH were increased …

Effect Of Kisspeptin On Regulation Of Growth Hormone, Brian K. Whitlock, Joseph A. Daniel, Robyn R. Wilborn, Herris S. Maxwell, Barbara P. Steele, James L. Sartin

Brian K Whitlock, PhD, DVM, DACT

Kisspeptin ( KP ), a neuroendocrine regulator of reproduction, is hypothesized to be an integrator of metabolism and hormones critical to the regulation of reproduction. Lactation is associated with enhanced growth hormone (GH) responsiveness and reduced fertility. Our study was designed to determine the effects of lactation on KP-stimulated GH and luteinizing hormone (LH) secretion. Five non-lactating and five lactating dairy cows were used in the study. Experiments were conducted with lactating cows at weeks 1, 5 and 11 after parturition. The experimental treatments ( saline and KP [100 and 400 pmol / kg body weight]) were given intravenously and …

The Effect Of Kisspeptin Receptor Agonist (Ftm080) On Luteinizing Hormone In Sheep, Brian K. Whitlock, Joseph A. Daniel, Maria Hes, Barbara P. Steele, James L. Sartin, S. Oishi, N. Fujii

Brian K Whitlock, PhD, DVM, DACT

Kisspeptin receptor (Kiss1r) agonists with increased half-life and similar efficacy to kisspeptin (KP) in vitro potentially may provide beneficial applications in breeding management of many species. However, many of these agonists have not been tested in vivo. This study was designed to test the effect of a Kiss1r agonist (FTM080) on luteinizing hormone (LH) in vivo. Sheep were treated with FTM080 (500 pmol/kg BW) or sterile water in a 2-ml bolus via the jugular cannula. Serial blood samples were collected every 15-min before (1 hr) and after (1 hr) treatment. Intravenous (IV) injection of FTM080 increased (P < 0.05) LH plasma concentrations through the 45-min sample following treatment. Moreover, the area under the curve of LH in the period from 0 to 60-min following FTM080 treatment was also increased (P < 0.05). These data provide evidence to suggest that FTM080 stimulates the gonadotropic axis of ruminants in vivo.

Selected Hormonal And Neurotransmitter Mechanisms Regulating, James L. Sartin, Joseph A. Daniel, Brian K. Whitlock, Robyn R. Wilborn

Brian K Whitlock, PhD, DVM, DACT

Appetite control is a major issue in normal growth and in suboptimal growth performance settings. A number of hormones, in particular leptin, activate or inhibit orexigenic or anorexigenic neurotransmitters within the arcuate nucleus of the hypothalamus, where feed intake regulation is integrated. Examples of appetite regulatory neurotransmitters are the stimulatory neurotransmitters neuropeptide Y (NPY), agouti-related protein (AgRP), orexin and melanin-concentrating hormone and the inhibitory neurotransmitter, melanocyte-stimulating hormone (MSH). Examination of messenger RNA (using in situ hybridization and realtime PCR) and proteins (using immunohistochemistry) for these neurotransmitters in ruminants has indicated that physiological regulation occurs in response to fasting for several …

Effect Of Leukemia Inhibitory Factor On Feed Intake And Body Temperature In Sheep, James L. Sartin, D L. Marks, Brian K. Whitlock, Joseph A. Daniel, Barbara P. Steele

Brian K Whitlock, PhD, DVM, DACT

Leukemia inhibitory factor (LIF) has been suggested to function as a potent inhibitor of feed intake in rodents. These studies were designed to determine whether LIF was found in the ovine hypothalamus and whether LIF inhibited feed intake in sheep. Sheep hypothalami were used to clone LIF to indicate presence of the gene in the hypothalamus. The sequence was similar to published data. Another group of sheep were provided intraventricular (ICV) cannulas and injected with doses of LIF at 250, 500, 1000 and 2500 ng per sheep, ICV. Feed intake was inhibited by the 1000 and 2500 ng dose (trt, …

Changes In Plasma Concentrations Of Growth Hormone And Luteinizing Hormone In Ewes Following Central And Peripheral Treatment With Kisspeptin, Brian K. Whitlock, Joseph A. Daniel, Barbara P. Steele, James L. Sartin

Brian K Whitlock, PhD, DVM, DACT

Kisspeptin (KP), a neuroendocrine regulator of gonadotropin releasing hormone, has been hypothesized as an integrator of nutrition and hormones critical to metabolism and regulation of reproduction. Recent evidence suggests growth hormone (GH) secretion may be influenced by KP. The objective of this study was to determine if the GH stimulatory effect of KP is due to actions on the hypothalamus or anterior pituitary gland in ewes. Adult ovariectomized ewes (n=8) were fitted with intracerebroventricular (ICV) cannula to facilitate central administration of experimental treatments. Ewes received one of eight treatments [four intravenously (IV) and four ICV]. Peripheral treatments [0 (Veh), 100, …

Changes In Plasma Concentrations Of Leptin In Ewes During Pregnancy, Joseph A. Daniel, A B. Milam, M E. Gafnea, Brian K. Whitlock, D H. Keisler

Brian K Whitlock, PhD, DVM, DACT

Previous research has demonstrated circulating concentrations of leptin increase in ewes during mid pregnancy then decline in late pregnancy and early lactation. The objective of this study was to more narrowly define the timing of changes in circulating concentrations of leptin with pregnancy in ewes. Katahdin ewes (n= 19) located at latitude 34.275 and longitude -85.183 (Mount Berry, GA) were utilized. Blood samples were collected weekly via jugular veinpuncture beginning immediately before ram exposure on September 23 and continuing until 4 weeks post-lambing. Ewes were exposed to a ram fitted with a marking harness for a 63 day breeding season. …

Farm Focus - Spring 2010, Brian K. Whitlock, Matt Welborn, Maria Prado, Amy Plummer

Brian K Whitlock, PhD, DVM, DACT

No abstract provided.

Farm Focus - Spring 2009, Brian K. Whitlock, Matt Welborn, Maria Prado, Amy Plummer

Brian K Whitlock, PhD, DVM, DACT

No abstract provided.

Farm Focus - Fall 2009, Brian K. Whitlock, Matt Welborn, Maria Prado, Amy Plummer

Brian K Whitlock, PhD, DVM, DACT

No abstract provided.

The Effects Of Lactation And Negative Energy Balance On Kisspeptin-Stimulated Luteinizing Hormone And Growth Hormone In Dairy Cows, Brian K. Whitlock, Joseph A. Daniel, Robyn R. Wilborn, Herris S. Maxwell, Barbara P. Steele, James L. Sartin

Brian K Whitlock, PhD, DVM, DACT

Kisspeptin, a neuroendocrine regulator of gonadotropin releasing hormone, is hypothesized to integrate nutrition and hormones critical to metabolism and the regulation of reproduction. Since the negative energy balance of early lactation is associated with reduced fertility via suppression of gonadotropin secretion and enhanced growth hormone (GH) responsiveness, this experiment was designed to determine the effects of stage of lactation and negative energy balance on kisspeptin-10 (Kp-10) stimulated luteinizing hormone (LH) and GH concentrations. Five nonlactating [5.1 ± 0.8 (SEM) years; 577 ± 19 kg body weight (BW)] and five lactating [4.1 ± 0.6 years; 608 ± 11 kg BW] multiparous …

Short Communication: Relationship Between Body Growth And Mammary Development In Dairy Heifers, L F. Silva, M J. Vandehaar, Brian K. Whitlock, R P. Radcliff, H A. Tucker

Brian K Whitlock, PhD, DVM, DACT

Our objective was to determine if prepubertal rate of body weight (BW) gain, independent of diet, was related to mammary development of dairy heifers. Data from two studies recently conducted at Michigan State University were used to identify factors, within a dietary treatment group, that would account for variation in first lactation milk production or amount of mammary parenchymal DNA at the time of puberty. Factors analyzed for variation in milk production during first lactation were: postpartum BW, prepubertal BW gain, gestational BW gain, postpartum BW gain, body condition score (BCS) at breeding, and BCS at calving. Factors analyzed for …

Effect Of Dietary Protein On Prepubertal Mammary Development In Rapidly Growing Dairy Heifers, Brian K. Whitlock, M J. Vandehaar, L F. Silva, H A. Tucker

Brian K Whitlock, PhD, DVM, DACT

The objective was to determine whether increased dietary protein would enhance mammary development in prepubertal heifers fed for rapid body growth (1.2 kg/d). Fifty-four Holstein heifers (weighing approximately 134 kg) were assigned to one of three treatments. Heifers were fed a total mixed ration with metabolizable energy at 2.85 Mcal/kg and metabolizable protein at low, standard, or high concentrations (37, 41, or 44 g/Mcal of metabolizable energy, respectively) from 3.5 mo of age until slaughter at approximately 46 d after puberty. Heifers fed low, standard, and high protein gained 1130, 1170, and 1180 g/d, respectively. Dietary protein did not affect …

Chemical Bird Repellents: Possible Use In Cyanide Ponds, Larry Clark, Pankaj Shah

Larry Clark

No abstract provided.

Avoidance Of Bird Repellents By Mice, Dale Nolte, J. Russell Mason, Larry Clark

Larry Clark

It is believed that mammalian chemosensory initants are not aver­ sive to birds and vice versa. Nevertheless, few avian repellents have been tested against mammals. For that reason, we evaluated the efficacy of 1.0% w/v methyl anthranilate, orthoaminoacetophenone, 2-amino-4' ,5 '-methoxy­ acetophenone, 2-methoxyacetophenone, and veratryl amine as mouse repel­ lents in 3-hr no-choice drinking tests. Relative to ingestion of plain water, all test substances significantly reduced (P < 0.05) intake. Orthoaminoaceto­phenone was the most effective repellent, with intake reduced to levels sta­tistically indistinguishable from zero.

Evaluation Of A Pelleted Bait Containing Methyl Anthranilate As A Bird Repellent, J. Russell Mason, Larry Clark, Timothy Miller

Larry Clark

No-till agriculture involves the use of granular pesticide formulations, chemically treated seeds, and pelleted baits. Some of these may accidentally kill birds. We have tested whether methyl anthranilate (MA), a known bird repellent, would eliminate consumption of a pelleted bait. In two laboratory experiments and an outdoor aviary trial, cowbirds (Molothrus ater Bodd.) were presented with pellets containing pesticide and MA, pellets containing pesticide but no MA, and carrier pellets without pesticide or MA. Consumption of any formulation was low, but the addition of MA significantly decreased bait loss in the laboratory, and prevented the disappearance of bait in the …

Nonlethal Rodent Repellents: Differences In Chemical Structure And Efficacy From Nonlethal Bird Repellent, Dale Nolte, J. Russell Mason, Larry Clark

Larry Clark

At least some anthranilates (e.g., methyl anthranilate), and ace­ tophenones (e.g., orthoaminoacetophenone) are aversive to mice as well as to birds. Here we systematically examined nine acetophenone isomers (ortho, meta, para) and moieties (amino, hydroxy, methoxy) previously tested as drinking and feeding repellents for European starlings (Sturnus vulgaris). All nine substances reduced intake by mice in single-bottle tests. When molecular characteristics were examined, amino group reactivity and, to a lesser extent, isomeric position (i.e., resonance), were related to the strength of the avoid­ ance response. Unlike effective avian repellents, the presence of intramo lecular hydrogen bonds did not appear to …

Interaction Between Sensory And Postingestional Repellents In Starlings: Methyl Anthranilate And Sucrose, Larry Clark, J. Russell Mason

Larry Clark

Ingestion of concentrated sucrose solutions causes sickness in sucrase-defi­ cie_nt birds. As a result, some suggest that sucrose may represent an environmentally safe avian repellent. In the present experiments, we compared the repellency of sucrose to that of methyl anthranilate (MA), a known avian repellent. We also tested mixtures of sucrose and MA to investigate whether repellency could be enhanced, relative to sucrose or MA presentealo'!e. The results showed that the MA was strongly avoided in both drinking anf edmtnals. Conversely, only high sucrose concentrations were avoided, and only in dnnkmg tnals. No combination of MA and sucrose was as …

Odor Thresholds In Passerines, Larry Clark, K.V. Avilova, N.J. Bean

Larry Clark

Eight species of passerines were evaluated for their ability to form conditioned responses to odor stimuli. Only 5 species met training criteria and were tested for odor detection thresholds.

2. Detection thresholds were comparable to other passerines tested. Detection values were also similar to mammalian macrosmatic species, such as rats and rabbits. Thus, despite the poorly elaborated olfactory anatomy of passerines, these birds possess an adequate sense of smell.

3. Within the Passeriformes there is no correlation between olfactory acuity and relative size of the olfactory bulb. However, there is a correlation between acuity and olfactory bulb size across orders …

Information Content Of Prey Odor Plumes: What Do Foraging Leach's Storm Petrels Know?, Larry Clark, Pankaj Shah

Larry Clark

Electrophysiological responses to odor have been recorded for concen­ trations as low as 0.01 ppm for Manx shearwaters Puffinus puffinus and Black-footed Albatrosses Diomedea nigripes, indicating that relative to most birds, procellariiforms have a keen sense of smell (Wenzel and Sieck 1972, cf.clark 1991; Clark and Smeraski 1990; Clark and Mason 1989). Such acuity is not unexpected, given the extensive development of the olfactory anatomy of these species (Bang and Wenzel 1986). Field observations indi­ cate that Procellariiformes use their sense of smell to locate food (Grubb 1972; Hutchison and Wenzel 1980; Lequette, Verheyden and Jouventin 1989). -_ However, it …

Avian Chemical Repellency: A Structure-Activity Approach And Implications, Pankaj Shah, Russell Mason, Larry Clark

Larry Clark

Until recently, the discovery of avian sensory repellents has been empirical (MaRnn, AnAmR 'Inn l;qr\r FlR'l), Hm> !ilv!ilr, recent liltudilillil in our laboratory have shown that many avian repellents have similar perceptual and structural properties (Mason et al. 1989; Mason Clark and Shah 1991; Clark and Shah 1991; Clark, Shah and Mason 1991; Shah, Clark and Mason 1991). For example, methyl anthranilate, which has a grapy odor, is repel­ lent to birds (Kare and Pick, 1960). Ortho-aminoacetophenone has an odor and structure similar to that of methyl anthranilate, differing only in the substitution of a ketone for an ester group …

Prediction Of Avian Repellency From Chemical Structure: The Aversiveness Of Vanillin, Vanillyl Alcohol, And Veratryl Alcohol, Pankaj Shah, Larry Clark, Russel Mason

Larry Clark

The effectiveness of bird repellents is associated with the presence of an electron-withdrawing group (carbonyl or carboxyl) and an electron-donating group in resonance on a phenyl ring. The present experiments were designed to examine the relative importance of these structural features. European starlings (Sturnus vulgaris) were presented with vanillin, vanillyl alcohol, and veratryl alcohol in two-cup and one-cup feeding trials and in one-bottle drinking tests. In feeding trials, veratryl alcohol was significantly more aversive than the other two chemicals. In drinking tests. veratryl alcohol was repellent only at the highest concentration (0.5% ml/ml), and was lethal at that concentration and …