Open Access. Powered by Scholars. Published by Universities.®

Animal Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 10 of 10

Full-Text Articles in Animal Sciences

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 Oct 2011

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 Sep 2011

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 Aug 2011

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.


Determinants Of Local And Migratory Movements Of Great Lakes Double-Crested Cormorants, Alban Guillaumet, Brian S. Dorr, Guiming Wang, Jimmy D. Taylor Ii, Richard B. Chipman, Heidi Scherr, Jeff Bowman, Kenneth F. Abraham, Terry J. Doyle, Elizabeth Cranker Jun 2011

Determinants Of Local And Migratory Movements Of Great Lakes Double-Crested Cormorants, Alban Guillaumet, Brian S. Dorr, Guiming Wang, Jimmy D. Taylor Ii, Richard B. Chipman, Heidi Scherr, Jeff Bowman, Kenneth F. Abraham, Terry J. Doyle, Elizabeth Cranker

Brian S Dorr

We investigated how individual strategies combine with demographic and ecological factors to determine local and migratory movements in the double-crested cormorants (Phalacrocorax auritus). One hundred and forty-five cormorants were captured from 14 nesting colonies across the Great Lakes area and fitted with satellite transmitters. We first tested the hypotheses that sexual segregation, density-dependent effects, and the intensity of management operations influenced home range size during the breeding season. The influence of these factors appeared to be limited in part due to random variability in foraging and dispersal decisions at individual and colony levels. We also designed a statistical framework to …


अंत:स्थलीय मात्स्यिकी - उत्पादन एवं संसाधन प्रबंधन (Inland Fisheries -Production And Resource Management), A. P. Sharma, M. K. Bhandhopadhyay, Ganesh Chandra, A. Roy Jun 2011

अंत:स्थलीय मात्स्यिकी - उत्पादन एवं संसाधन प्रबंधन (Inland Fisheries -Production And Resource Management), A. P. Sharma, M. K. Bhandhopadhyay, Ganesh Chandra, A. Roy

Ganesh Chandra

No abstract provided.


Acute Toxicity Of Mercury And Chromium To Clarias Batrachus (Linn), Azhaguraj Ramakrishnan Jan 2011

Acute Toxicity Of Mercury And Chromium To Clarias Batrachus (Linn), Azhaguraj Ramakrishnan

Azhaguraj Ramakrishnan

Pollution of the aquatic ecosystems by heavy metals is a worldwide problem. In the present study, Clarias batrachus was exposed to Mercury and Chromium for 24, 48, 72 and 96 hrs. The median lethal concentration (LC50) of mercury to C. batrachus for 24, 48, 72 and 96 h of exposure were 1.4 ppm, 1.2 ppm, 1.0 ppm and 0.8 ppm respectively. The median lethal concentration (LC50) of chromium to C. batrachus for 24, 48, 72 and 96 h of exposure were 120 ppm, 115 ppm, 110 ppm and 102 ppm respectively. The acute toxicity levels were derived from LC50 concentrations …


Socioeconomic Characteristics And Perceptions Of Cattle Keepers And Constraints To Cattle Production In Western Kenya, Joshua O. Amimo, S Thumbi, B O. Inyangala, J O. Junga, R O. Mosi Jan 2011

Socioeconomic Characteristics And Perceptions Of Cattle Keepers And Constraints To Cattle Production In Western Kenya, Joshua O. Amimo, S Thumbi, B O. Inyangala, J O. Junga, R O. Mosi

Joshua O Amimo

No abstract provided.


Factors Influencing Reproductive Performance Of Cows From Different Nguni Ecotypes In Southern Mozambique, S Maciel, O Mwai, Joshua O. Amimo, S Moyo, M Scholtz, F Neser, M Martins Jan 2011

Factors Influencing Reproductive Performance Of Cows From Different Nguni Ecotypes In Southern Mozambique, S Maciel, O Mwai, Joshua O. Amimo, S Moyo, M Scholtz, F Neser, M Martins

Joshua O Amimo

No abstract provided.


Ameliorating The Effects Of The Digenetic Trematode, Bolbophorus Damnificus On The Channel Catfish Industry, Lester Khoo, David J. Wise, Linda M. Pote, Andrew J. Mitchell, Todd S. Byars, Marlena C. Yost, Cynthia M. Doffitt, Brian S. Dorr Jan 2011

Ameliorating The Effects Of The Digenetic Trematode, Bolbophorus Damnificus On The Channel Catfish Industry, Lester Khoo, David J. Wise, Linda M. Pote, Andrew J. Mitchell, Todd S. Byars, Marlena C. Yost, Cynthia M. Doffitt, Brian S. Dorr

Brian S Dorr

No abstract provided.


A New Policy For Management Of Double-Crested Cormorants In The United States And An Example Of Its Implementation., Shauna L. Hanisch, Brian S. Dorr, Peter H. Butchko Jan 2011

A New Policy For Management Of Double-Crested Cormorants In The United States And An Example Of Its Implementation., Shauna L. Hanisch, Brian S. Dorr, Peter H. Butchko

Brian S Dorr

In the fall of 2003, the U.S. Fish and Wildlife Service (USFWS), in cooperation with USDA-Wildlife Services (USDA-WS), completed an Environmental Impact Statement (EIS) for the management of Double-crested Cormorants (DCCOs) in the United States. The USFWS subsequently published new regulations to implement the EIS proposed strategy. One part of the new regulations, a “public resource depredation order” (PRDO), allows state wildlife agencies, tribes, and USDA-WS to control DCCOs on a localized level to protect fish, wildlife, plants, and their habitats in 24 states. We’ll discuss this new policy and will highlight the management activities, including monitoring and evaluation efforts, …