Frequency of ovarian follicular cysts, reasons for culling, and fertility in Holstein-Friesian cows given gonadotropin-releasing hormone at two weeks after parturition.     

J H Britt  D S Harrison  D A Morrow 《American journal of veterinary research》1977,38(6):749-751

Holstein-Friesian cows (n=204) were given saline solution or 200 microgram of gonadotropin-releasing hormone (GnRH) by intramuscular injection at 8 to 23 days after parturition. Of cows culled, fewer GnRH-treated cows were culled for infertility, compared with number of cows given saline solution (26 vs 57%; P less than 0.05). Frequency of ovarian follicular cysts was reduced from 15.2% in controls to 5.7% for cows given GnRH (P less than 0.01). The interval to 1st insemination, interval to conception, and inseminations per conception did not differ among saline solution or GnRH-treated cows which remained in the herds. These data provide evidence for reduction in infertility and reproductive disorders in early postpartum dairy cows given GnRH as a prophylactic.  相似文献   

Morphine suppresses luteinizing hormone concentrations in transiently weaned sows and delays onset of estrus after weaning     

J D Armstrong  R R Kraeling  J H Britt 《Journal of animal science》1988,66(9):2216-2223

Lactating sows were used to evaluate effects of morphine and suckling on secretion of LH and prolactin (PRL) and occurrence of estrus after weaning. In the first experiment, crossbred multiparous sows nursing 7.9 +/- .4 pigs per litter at 25.2 +/- .3 d of lactation were subjected to one of three treatments during the middle 8-h segment of a 24-h experimental period. Treatments were infusion (i.v.) of morphine (200 mg/h) with the litter present (n = 4) or transiently weaned (n = 4), or transient weaning of litters without morphine (n = 4). Transient weaning decreased (P less than .05) prolactin and increased (P less than .05) the frequency of LH pulses and average concentration of LH. Infusion of morphine caused transient hyperthermia and suppressed (P less than .05) LH release in two of four sows nursing litters and in four sows whose litters were absent. Infusion of morphine, in the presence or absence of litters, suppressed PRL during the middle and last 8-h segments. A second experiment was conducted to test the hypothesis that chronic administration of morphine delays onset of estrus after weaning. Primiparous Duroc sows were assigned at weaning (53 to 63 d postpartum) to receive morphine (n = 10) or saline (n = 11). Saline (1.5 ml) or morphine (75 mg) was administered s.c. three times a day for 5 d after weaning. Onset of estrus after weaning was delayed in sows given morphine compared with those given saline (9.7 +/- .4 vs 5.2 +/- .3 d, respectively; P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Technical note: use of slow-release estradiol and prostaglandin F2alpha to induce pseudopregnancy and control estrus in gilts     

Cushman RA  Davis PE  Boonyaprakob U  Hedgpeth VS  Burns PJ  Britt JH 《Journal of animal science》1999,77(11):2883-2885

We determined whether a single injection of slow-release estradiol-17beta (SRE2) would induce pseudopregnancy in gilts and whether PGF2alpha would regress the corpora lutea (CL) of pseudopregnancy. Crossbred gilts (n = 40) were induced to ovulate by treatment with 400 IU of hCG + 200 IU of eCG (PG600, Intervet, Millsboro, DE) given at 180 d of age (d = 0). On d 14, gilts were injected i.m. with one of five doses (n = 8 gilts/dose) of SRE2 (0, 12.5, 25, 50, or 100 mg). Blood samples were collected before SRE2 and twice weekly until d 73 to monitor serum progesterone (P4) and estradiol (E2). On d 59, gilts received (i.m.) 10 mg of PGF2alpha (Lutalyse, Pharmacia Upjohn, Kalamazoo, MI) and were checked for estrus for 7 d. On d 62, mammary development was scored (0 = no development; 1 = some development; 2 = teat and gland development) by a neutral observer. Treatment with SRE2 increased (P < .05) peak E2 concentrations, duration of luteal function, and mammary gland score. There were no differences (chi-square, P > .05) among doses of SRE2 in the percentage of pseudopregnant gilts that showed luteolysis after PGF2alpha. We conclude that a single injection of SRE2 can induce pseudopregnancy and that the CL can be regressed with PGF2alpha, providing a simple method for controlling estrus in gilts.  相似文献   

Progressive hindlimb paraparesis in a goat associated with a vascular hamartoma     

Middleton JR  Valdez R  Britt LG  Parish SM  Tyler JW 《The Veterinary record》1999,144(10):264-265

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Latitudinally distinct stocks of Atlantic cod face fundamentally different biophysical challenges under on-going climate change     

Olav Sigurd Kjesbu  Maud Alix  Anne Britt Sandø  Espen Strand  Peter J. Wright  David G. Johns  Anders Thorsen  C. Tara Marshall  Kjell Gunnar Bakkeplass  Frode B. Vikebø  Mari Skuggedal Myksvoll  Geir Ottersen  Bridie J. M. Allan  Maria Fossheim  Jan Erik Stiansen  Geir Huse  Svein Sundby 《Fish and Fisheries》2023,24(2):297-320

The reproductive success of marine ectotherms is especially vulnerable in warming oceans due to alterations in adult physiology, as well as embryonic and larval survival prospects. These vital responses may, however, differ considerably across the species' geographical distribution. Here we investigated the life history, focusing on reproductive ecology, of three spatially distant populations (stocks) of Atlantic cod (Gadus morhua, Gadidae) (50–80° N), in the Irish/Celtic Seas-English Channel Complex, North and Barents Seas, under past and projected climate. First, experimental tracking of spawning behaviour evidenced that the ovulation cycle is highly distressed at ≥9.6 (±0.25)°C (T_up). This knife-edge threshold resulted in erratic spawning frequencies, whereas vitellogenin sequestration remained unaffected, indicating endocrine rather than aerobic scope constraints. Cod in the Celtic Sea-English Channel are, therefore, expected to show critical stock depensation over the next decades as spawning grounds warm above T_up, with Irish Sea cod subsequently at risk. Second, in the relatively cooler North Sea, the northward retraction of Calanus finmarchicus (Calanidae) and Para-Pseudocalanus spp. (Clausocalanidae) (1958–2017) limit cod larvae feeding opportunities, particularly in the southernmost subarea. However, the contrasting increase in Calanus helgolandicus (Calanidae) does not counteract this negative effect, likely because cod larvae hatch ahead of its abundance peaks. Overfishing again comes as a twin effect. Third, in the still relatively cold Barents Sea, the sustainably harvested cod benefit from improved food conditions in the recent ice-free polar region but at the energetic cost of lengthier and faster spawning migrations. Consequently, under climate change local stocks are stressed by different mechanistic factors of varying management severity.  相似文献   

RADIOGRAPHIC DIAGNOSIS–ENGORGED TICKS APPEARING AS DISTINCTRADIOGRAPHIC OPACITIES     

Lisa G.  Britt  DVM  MS  David D.  Barbee  DVM  MS  Michael P.  Moore  DVM  MS  Erik H.  Stauber  DVM  PhD 《Veterinary radiology & ultrasound》2000,41(2):145-146

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Lower Lethal Temperature for Juvenile Cobia Rachycentron Canadum     

Dusty L. McDonald  Britt W. Bumguardner 《Journal Of Applied Aquaculture》2013,25(1):25-29

Cobia are a migratory marine species that have recently gained popularity as foodfish in the aquaculture market and for stocking. Unfortunately, when culturing these species, aquaculturalists may unknowingly expose these fish to temperature extremes not normally experienced in situ. We set out to test for the critical thermal minimum temperatures of juvenile cobia by exposing them to a simulated freeze, at a drop rate of 0.33°C per hour. We observed and documented behavioral effects due to low temperature exposure using criteria for loss of equilibrium and death. We determined that the median temperature for loss of equilibrium was 12.1 ± 0.40°C and the median lethal temperature was 9.7 ± 0.28°C for low temperature tolerance. We recommend that precautions be taken well before water temperatures reach 13°C in a freeze scenario.  相似文献   

Effects of different step‐wise temperature increment regimes during egg incubation of Atlantic cod (Gadus morhua L.) on egg viability and newly hatched larval quality          下载免费PDF全文

Velmurugu Puvanendran  Inger‐Britt Falk‐Petersen  Hege Lysne  Helge Tveiten  Hilde Toften  Stefano Peruzzi 《Aquaculture Research》2015,46(1):226-235

We carried out an experiment to determine how rapidly the early incubation temperature of Atlantic cod eggs can be increased without affecting normal embryonic development and hatching. Atlantic cod eggs were incubated at a constant low temperature (4.5 ± 0.5°C; T5 – control) and four temperature increment treatments where the temperatures were increased stepwise from 4.5°C at zygote stage to 9.5 ± 05°C (T1‐8 h, T2‐32 h, T3‐64 h and T4‐96 h). Embryonic cell symmetry, embryonic mortality, hatching success and larval skeletal abnormalities, length and yolk sac volume were recorded. Larval samples were also taken at hatch for histological analysis. Except for higher egg mortality and lower hatching success in the T1, the differences among experimental groups were minor. Cell asymmetries and embryo mortalities were not significantly different between the control and T2–T4 treatment groups. Control larvae were significantly longer and had smaller yolk reserves at hatch than T1–T4 larvae and larvae from T2 had the largest yolk reserves. Tissue and organ histology of hatched larvae were similar. Considering embryonic cleavage pattern, hatching success and larval morphology and histology, a gradual increment of temperature in 32 h seems to be the better choice for future developmental programming studies in Atlantic cod.  相似文献   

The composition of mobile matter in a floodplain topsoil: A comparative study with soil columns and field lysimeters          下载免费PDF全文

Andreas Fritzsche  Britt Pagels  Kai U. Totsche 《植物养料与土壤学杂志》2016,179(1):18-28

Floodplain soils are characterized by frequent and extreme redox changes caused by inundation with river water or imbibition of groundwater. Depending on the duration and extent of inundation, biogeochemical processes run at sub‐/anoxic conditions, which may result in the mobilization and relocation of dissolved and particulate matter within the soil. In this study, we investigated the effect of inundation events on the composition of mobilized matter in the topsoil horizon of a floodplain soil. We conducted experiments with soil columns in the laboratory and gravitational lysimeters in the field to identify redox‐mediated (im)mobilization processes and to estimate their relevance under field conditions. The lysimeters were filled with topsoil monoliths and run under in situ conditions during a ≈ 2.5‐y period. The soil columns were run with the same soil material either under strictly anoxic or mixed oxic–anoxic conditions. Effluents from mixed oxic–anoxic soil were composed fundamentally different [comparably high: Mn, Al, nitrate, sulfate; comparably low: pH, organic C (OC); not detected: Fe, As] compared to effluents from strictly anoxic soil (comparably high: pH, Fe, Mn, OC, As; comparably low: Al; not detected: nitrate, sulfate). Matter, which was mobile under anoxic conditions (e.g., Fe, As, OC), was effectively immobilized as soon as the mobile phase passed anoxic–oxic boundaries within soil (exception: Mn). We assume that the solution in the soil monoliths always passed such anoxic–oxic boundaries during downwards migration independent of lysimeter flooding with river water. This is indicated by the similar composition of the lysimeter seepage water and the effluents from mixed oxic–anoxic soil columns. Both solutions contained “fingerprints” from anoxic (Mn) and oxic conditions (nitrate). Inundations with river water and the duration of these floods (1–22 d) did not affect the composition of the lysimeter seepage water. In conclusion, immediate changes in the composition of the solution, which enters either the subsoil or nearby receiving waters, cannot be expected from regular topsoil flooding.  相似文献   

Osteochondrosis of the vertebrae in a dog.          下载免费PDF全文

J E Bartels  A S Dorn    A L Britt 《The Canadian veterinary journal. La revue veterinaire canadienne》1970,11(3):47-51

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