Husbandry Factors and the Resumption of Luteal Activity in Open and Zero‐Grazed Dairy Cows in Urban and Peri‐Urban Kampala,Uganda     

BM Kanyima  R Båge  DO Owiny  T Ntallaris  J Lindahl  U Magnusson  MG Nassuna‐Musoke 《Reproduction in domestic animals》2014,49(4):673-678

The study investigated the influence of selected husbandry factors on interval to resumption of post‐partum cyclicity among dairy cows in urban and peri‐urban Kampala. A prospective study of 85 day post‐partum period of 59 dairy cows in open (n = 38) and zero grazing (n = 21) systems was conducted on 24 farms. Cows of parity 1–6 were recruited starting 15–30 days post‐partum. Progesterone (P4) content in milk taken at 10–12 day intervals was analysed using ELISA. The cow P4 profiles were classified into ‘normal’ (< 56 days), ‘delayed’ (> 56 days), ‘ceased’ or ‘prolonged’ (if started < 56 days but with abnormal P4 displays) resumption of luteal activity and tested for association with husbandry and cow factors. Of the 59 cows, luteal activity in 81.4% resumed normally and in 18.6%, delayed. Only 23.7% maintained regular luteal activity, while the others had ceased (10.2%), prolonged (37.3%) or unclear luteal activity (20.3%). There were no differences between open and zero‐grazed cows. Milk production was higher (p < 0.05) in zero than open grazing, in urban than peri‐urban and in cows fed on brew waste (p < 0.001) compared with mill products and banana peels. Results suggest that luteal activity resumes normally in a majority of cows, although only a minority experienced continued normal cyclicity once ovulation had occurred, in the two farming systems irrespective of feed supplements or water, and that supplementing with brew waste is beneficial for milk production.  相似文献   

Adatom pairing structures for Ge on si(100): the initial stage of island formation     

XR Qin  MG Lagally 《Science (New York, N.Y.)》1997,278(5342):1444-1447

With the use of scanning tunneling microscopy, it is shown that germanium atoms adsorbed on the (100) surface of silicon near room temperature form chainlike structures that are tilted from the substrate dimer bond direction and that consist of two-atom units arranged in adjoining substrate troughs. These units are distinctly different from surface dimers. They may provide the link missing in our understanding of the elementary processes in epitaxial film growth: the step between monomer adsorption and the initial formation of two-dimensional growth islands.  相似文献   

Stimulation of bone formation in vitro and in rodents by statins     

Mundy G  Garrett R  Harris S  Chan J  Chen D  Rossini G  Boyce B  Zhao M  Gutierrez G 《Science (New York, N.Y.)》1999,286(5446):1946-1949

Osteoporosis and other diseases of bone loss are a major public health problem. Here it is shown that the statins, drugs widely used for lowering serum cholesterol, also enhance new bone formation in vitro and in rodents. This effect was associated with increased expression of the bone morphogenetic protein-2 (BMP-2) gene in bone cells. Lovastatin and simvastatin increased bone formation when injected subcutaneously over the calvaria of mice and increased cancellous bone volume when orally administered to rats. Thus, in appropriate doses, statins may have therapeutic applications for the treatment of osteoporosis.  相似文献   

A selective inhibitor of eIF2alpha dephosphorylation protects cells from ER stress   总被引：1，自引：0，他引：1  

Boyce M  Bryant KF  Jousse C  Long K  Harding HP  Scheuner D  Kaufman RJ  Ma D  Coen DM  Ron D  Yuan J 《Science (New York, N.Y.)》2005,307(5711):935-939

Most protein phosphatases have little intrinsic substrate specificity, making selective pharmacological inhibition of specific dephosphorylation reactions a challenging problem. In a screen for small molecules that protect cells from endoplasmic reticulum (ER) stress, we identified salubrinal, a selective inhibitor of cellular complexes that dephosphorylate eukaryotic translation initiation factor 2 subunit alpha (eIF2alpha). Salubrinal also blocks eIF2alpha dephosphorylation mediated by a herpes simplex virus protein and inhibits viral replication. These results suggest that selective chemical inhibitors of eIF2alpha dephosphorylation may be useful in diseases involving ER stress or viral infection. More broadly, salubrinal demonstrates the feasibility of selective pharmacological targeting of cellular dephosphorylation events.  相似文献   

GAS DISCHARGE WAVE-LENGTH LIST IN THE EXTREME ULTRA-VIOLET     

Macinnes JM  Boyce JC 《Science (New York, N.Y.)》1930,72(1856):90-91

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Atomistic Processes in the Early Stages of Thin-Film Growth     

Z Zhang  MG Lagally 《Science (New York, N.Y.)》1997,276(5311):377-383

Growth of thin films from atoms deposited from the gas phase is intrinsically a nonequilibrium phenomenon governed by a competition between kinetics and thermodynamics. Precise control of the growth and thus of the properties of deposited films becomes possible only after an understanding of this competition is achieved. Here, the atomic nature of the most important kinetic mechanisms of film growth is explored. These mechanisms include adatom diffusion on terraces, along steps, and around island corners; nucleation and dynamics of the stable nucleus; atom attachment to and detachment from terraces and islands; and interlayer mass transport. Ways to manipulate the growth kinetics in order to select a desired growth mode are briefly addressed.  相似文献   

Whooping crane recruitment enhanced by egg removal     

Mark S. Boyce  Subhash R. Lele 《Biological conservation》2005,126(3):395-401

To facilitate recovery through captive breeding and foster-parenting programs of the endangered whooping crane, one of two eggs was removed from 62% of nests in Wood Buffalo National Park during 1967-1996. Egg removals were justified because cranes usually rear a single chick; the other dies to siblicide or predation. Concerns exist that the wild population might have recovered even faster if nests had not been disturbed. Here we show, contrary to expectation, that removing one of two eggs from a whooping crane nest actually increases the probability of nest success, and this effect is highly correlated with the dynamics of predators in the nesting area. These results beg the question: why do whooping cranes lay two eggs? We attribute two-egg clutches to occasional “good years” in which both chicks survive, compensating for higher mortality in two-egg broods. Egg removal has benefited conservation allowing establishment of several captive flocks, supporting reintroduction of two new populations, and reducing the variance in reproductive success of the wild flock thereby minimizing extinction risk.  相似文献   

Mortality of yellowtail flounder, Limanda ferruginea (Storer), eggs: effects of temperature and hormone-induced ovulation     

Trevor S. Avery  Danny Boyce  Joseph A. Brown 《Aquaculture (Amsterdam, Netherlands)》2004,230(1-4):297-311

Yellowtail flounder, Limanda ferruginea (Storer, 1839), is a highly marketable fish species that used to be a significant groundfish in the northwest Atlantic region. The potential of yellowtail flounder for mass rearing has recently been investigated, but studies into aspects of mortality during early ontogeny are lacking. We investigated the impact of spawning inducement on mortality of eggs from fertilisation until hatch, and the effects of rearing temperature on mortality and hatching time in this multiple batch spawning flounder. An ash-free dry mass (AFDM) technique for determining mortality was employed. This technique reduced rearing tank disturbances and provided quantitative mortality estimates. We found (1) that spontaneously ovulated (SO) mean egg mass (AFDM 24.84±0.73 μg) was significantly higher than mean egg mass from induced ovulation (IO) (AFDM 20.09±0.54 μg); (2) that mortality of SO eggs was lower than IO eggs (p=0.028), (3) that SO eggs reached a relatively constant (maximum) mortality by about day 3 and IO eggs by about day 5; (4) that there was no significant difference in mortality between eggs incubated at 10 °C and those incubated at 4 °C (p=0.320); and (5) that time to 100% hatch took significantly longer for eggs incubated at 4 °C (256.0±73.5 h) than those incubated at 10 °C (77.9±11.6 h) (p=0.003). There was considerable variation in egg mortality among batches and females; nevertheless, general trends indicate that GnRHa-induction of ovulation tends to decrease egg quality. In addition, the AFDM technique was an easily employed and accurate method of determining mortality. We recommend that unless coordination of spawning is important to a particular rearing protocol, induced ovulation should not be employed.  相似文献   

Pasteurella multocida Heddleston serovars 1 and 14 express different lipopolysaccharide structures but share the same lipopolysaccharide biosynthesis outer core locus     

Harper M  St Michael F  John M  Vinogradov E  Adler B  Boyce JD  Cox AD 《Veterinary microbiology》2011,150(3-4):289-296

Pasteurella multocida strains are classified using the Heddleston lipopolysaccharide (LPS) serotyping scheme into 16 serovars. Understanding the structural and genetic basis for this LPS typing scheme is important because protection against infections caused by P. multocida is generally considered to be serovar specific. Here we show that the serovar 14 type strain P2225 and the serovar 1 strains X73 and VP161 express similar LPS structures. However, the serovar 14 LPS lacks the terminal phosphocholine (PCho) residues present on the serovar 1 LPS and contains the 1,4-linked β-galactose but not the 1,6-linked β-galactose. Sequencing analysis of the LPS biosynthesis outer core loci of P2225 and the serovar 1 type strain X73 showed that they were nearly identical. However, the phosphocholine biosynthesis gene, pcgA of P2225 contained a 19bp nucleotide deletion. Complementation of P2225 with an intact pcgA resulted in an LPS structure identical to that expressed by serovar 1 strain VP161 and highly similar to that expressed by strain X73, with a 1,6-linked β-galactose and both terminal PCho residues. This study has shown unequivocally that strains belonging to serovar 1 and 14 share a common LPS outer core locus and that minor changes within this locus can dramatically alter the LPS structure expressed on the surface of P. multocida, and thus has implications into our understanding of the potential to generate cross-protective vaccines.  相似文献   

A natural infection of sheep with Ostertagia ostertagi     

MG O''CALLAGHAN  RR MARTIN  IJ McFARLAND 《Australian veterinary journal》1992,69(1):19-20

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