Fertility, health, and consanguineous marriages.     

P Hedrick 《Science (New York, N.Y.)》1991,254(5037):1434-1435

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Efficacy of ivermectin in a controlled-release capsule for the control of breech strike in sheep     

D. RUGG  D. THOMPSON  RP GOGOLEWSKI  GR ALLERTON  RA BARRICK  JS EAGLESON 《Australian veterinary journal》1998,76(5):350-354

Objective To investigate the efficacy of ivermectin in an intraruminal controlled-release capsule (CRC) against blowfly strike.
Design Pen and field trials with controls.
Animals Pen studies: Two breech strike trials involving 60 Romney and 60 Merino sheep. One body strike trial using 100 Merino sheep.
Field trials: Eight trials in New Zealand used 1000 Romney and Romney-cross sheep. Fifty Merino lambs in one trial in Australia.
Procedure Pen studies: Sheep were allocated to two equal groups. One was not treated, the other sheep received a CRC that delivered ivermectin at 20 μg/kg/day for 100 days. In the breech strike trials, each animal was given an oral laxative 2 days before exposure to adult Lucilia cuprina . In the body-strike trial, the sheep sheep were kept wet to increase susceptibility prior to the release of blowflies.
Field trials: Fifty or 200 sheep allocated to equal groups of nontreated or treated with the CRC and grazed at pasture exposed to natural blowfly challenge.
Results Pen studies: Breech strikes developed in 24 of 60 controls but in none of 60 CRC-treated sheep. There was a 35% reduction in the number of CRC-treated sheep struck on the body.
Field trials: The average number of breech strikes in CRC-treated sheep was reduced by 86% (P < 0.001). The number of body strikes in the treated groups was a reduced by 27% (P < 0.05).
Conclusion The ivermectin CRC is a useful aid in controlling breech strike, but provides only moderate reduction in the incidence of body strike.  相似文献   

Field trials evaluating ivermectin controlled-release capsules for weaner sheep and for breeding ewes     

GR ALLERTON  RP GOGOLEWSKI  D. RUGG  RE PLUE  RA BARRICK  JS EAGLESON 《Australian veterinary journal》1998,76(1):39-43

Objective To confirm the efficacy of ivermectin released from a controlled-release capsule administered to young sheep and to breeding ewes under field conditions. Design Randomised field trials. Procedure In each of ten field trials 25 weaned lambs were treated with ivermectin controlled-release capsules and 25 remained untreated. Eight similar field trials were conducted using adult ewes. Efficacy against infections of gastrointestinal nematodes was assessed by faecal egg counts and faecal larval culture. Body weights were recorded and faecal soiling of the breech wool (dags) was assessed. Results Nematode faecal egg counts in the two groups were not different (P = 0.13) before treatment in the weaner trials or before treatment in the ewe trials (P = 0.49), but thereafter eggs in the untreated sheep persisted, whereas counts in sheep given capsules were negligible (P ≤ 0.01). In the weaner trials, dag scores for the two groups were not different at the start of the trials (P = 0.18) but at the end, untreated sheep had significantly more dags (P = 0.04) than treated sheep. In the ewe trials, dag scores remained low in both groups. Weaners treated with the capsule gained 1.4 kg (95% CL: 0.7, 3.1) more weight over the 16 week trial period compared to untreated weaners (P = 0.01). Both groups of ewes lost weight as a result of parturition but the mean loss by week 16 was greater for untreated (3.7 kg) (95% CL: -5.1,-2.2) than for treated ewes (1.8 kg) (95% CL: -3.3, -0.4). The mean change in ewe body weight for the two groups was however not significant (P = 0.07). Differentiation of nematode larvae recovered from cultures of faeces from untreated animals indicated that the capsules were effective against the common parasites of sheep. Conclusion The capsule was efficacious against gastrointestinal nematodes judging from faecal egg counts. It has the potential to significantly reduce contamination of pasture with nematode eggs. Treated weaners had less dags for 16 weeks and gained more weight than untreated weaners.  相似文献   

Bovine ovarian stem cells differentiate into germ cells and oocyte‐like structures after culture in vitro          下载免费PDF全文

GB de Souza  JJN Costa  EV da Cunha  JRS Passos  RP Ribeiro  MVA Saraiva  R van den Hurk  JRV Silva 《Reproduction in domestic animals》2017,52(2):243-250

Stem cells have been isolated from ovaries, and their ability to differentiate into oocytes in vitro has been demonstrated for mice and human, but not for bovine species. The aims of this study were to isolate germline stem cells from bovine ovaries and to evaluate the effects of bone morphogenetic proteins (BMPs) 2 and 4, and follicular fluid on the differentiation of these stem cells into oocyte‐like structures. The ovarian stem cells were isolated and cultured in α‐MEM⁺ supplemented with BMP2, BMP4 or follicular fluid. On days 0 and 14, cells were evaluated for their morphological appearance, viability, expression of alkaline phosphatase and for markers of germ cell formation (VASA and DAZL) and oocyte development (GDF9, ZPA and SCP3) by qPCR. Levels of mRNA were analysed using ANOVA and Bonferroni test (p < .05). The results showed that at day 0, ovarian stem cells expressed specific markers of pluripotency (OCT4, SOX). In addition, these cells were positive for alkaline phosphatase, which is a marker commonly used to identify primordial germ cells (PGCs). After the period of differentiation, cells had morphological features that resemble PGCs and oocyte‐like cells (OLCs). An increase, ranging from five to 14 times, in the expression of VASA was observed in cells cultured in medium supplemented with BMPs and follicular fluid, while the increase in DAZL expression ranged from four to six times. In addition, OLCs had an increase in expression of mRNAs for GDF9, ZPA and SCP3 that ranged from two to eight times. In conclusion, OLCs can be differentiated in vitro from ovarian stem cells and BMPs and follicular fluid are effective in stimulating the expression of mRNAs for germ cell and oocyte markers.  相似文献   

Effects of Different Oocyte Activation Procedures on Development and Gene Expression of Porcine Pre‐Implantation Embryos     

RP Cervera  MA Silvestre  N Martí  E García‐Mengual  R Moreno  M Stojkovic 《Reproduction in domestic animals》2010,45(5):e12-e20

Among the factors that affect the efficiency of somatic cell nuclear transfer (SCNT) in pigs, the activation protocol is the most variable among the current SCNT procedures. The aim of this study is focused on defining an efficient activation treatment of porcine oocytes. In Experiment 1, we studied the effects of nine different oocyte activation procedures (including chemical‐ and electrical‐based treatments) on parthenogenetic embryo development. In Experiment 2, we studied the effect of the more efficient activation procedures on the gene expression profile of Oct4 and Igf2r in parthenogenetic blastocysts. In conclusion, ionomycin as a first calcium stimulus is not able to activate porcine oocytes efficiently in comparison with electric procedures. Electrical treatments with 6‐DMAP significantly increased the level of Oct4 expression, whereas the single and double pulse treatments alone maintained the same profile as the IVF group.  相似文献   

Effect of a hot environment on performance, carcass characteristics, and blood hormones and metabolites of pigs treated with porcine somatotropin.     

B A Becker  C D Knight  F C Buonomo  G W Jesse  H B Hedrick  C A Baile 《Journal of animal science》1992,70(9):2732-2740

A study was conducted to compare the effects of a single 100-mg recombinant porcine somatotropin (rpST) implant on performance, carcass characteristics, and blood hormones and metabolites of 40 finishing pigs exposed to either a thermoneutral (TN; 18 to 21 degrees C) or hot environment (H; 27 to 35 degrees C) for 28 or 35 d. Pigs in H gained at a slower rate (P less than .01) than pigs in TN. Control and rpST-treated pigs gained at similar rates in respective environments. The rpST-treated pigs consumed 13% less feed (P less than .01) than the control pigs in both environments, and pigs in H consumed 19% less feed (P less than .01) than pigs in TN. Feed efficiency for rpST-treated pigs was 15% better (P less than .01) than that for control pigs; environment had no effect on feed efficiency. When slaughtered, pigs treated with rpST had less (P less than .01) leaf fat and less (P less than .01) 10th rib backfat than control pigs. Pigs in H had a lower (P less than .01) final BW and less leaf fat and backfat than pigs in TN. The rpST and H had various effects on blood hormones and metabolites. The results demonstrated that the benefits of this form of rpST treatment achieved under TN were also achieved in H with no interactions between the hormone and environment.  相似文献   

Composition of pork carcasses by potassium-40 liquid scintillation detection: estimation and validation     

A L Siemens  R J Lipsey  W M Martin  M G Siemens  H B Hedrick 《Journal of animal science》1991,69(1):47-53

Liquid scintillation detection of potassium-40 was used to estimate pork carcass composition of 124 boars, barrows and gilts. Pigs were fed to five live weights (23, 45, 68, 91 and 114 kg) and 40K emissions were determined on live pigs in a whole body counter (WBC) equipped with a two-pi liquid scintillation detector. Then, pigs were slaughtered conventionally and the right side of each carcass was weighed, 40K emissions of this carcass side was determined in the WBC and total grams of potassium were calculated. The right side of each carcass was ground, sampled and analyzed for fat, protein, moisture and potassium. Fat, protein, moisture and overall potassium percentage means were 23.9 +/- 7.2, 16.5 +/- .94, 57.0 +/- 6.5 and .25 +/- .02, respectively. Whole body counter carcass potassium was highly correlated (P less than .01) to chemically determined carcass potassium (r = .70). Percentage of fat, protein and moisture prediction equations were formed by stepwise regression using the linear, quadratic and interactive effects of live animal and carcass side weight. Whole body counter live animal and carcass potassium and sex were utilized as independent variables. Carcass weight and 40K determined potassium of the carcass explained more of the variation in carcass composition than did live animal weight and 40K determined potassium of the live animal.  相似文献   

Comparison of market hog characteristics of pigs selected by feeder pig frame size or current USDA feeder pig grade standards     

A L Siemens  R J Lipsey  H B Hedrick  F L Williams  S W Yokley  M G Siemens 《Journal of animal science》1990,68(8):2217-2221

Two feeder pig grading systems were tested. Forty-five barrows were selected using current USDA Feeder Pig Grade Standards (U.S. No. 1, No. 2 and No. 3). Additionally, 45 barrows were selected using three frame sizes (large, medium and small). Pigs were slaughtered at 100, 113.5 of 127 kg live weight. Trimmed four lean cuts were separated into soft tissue, skin and bone. The skinless belly and soft tissue from the four lean cuts were ground separately and analyzed chemically. Data from each grading system were analyzed separately in a 3 X 3 factorial plan. Pigs selected using current USDA grade standards differed (P less than .05) for last rib backfat, 10th rib fat depth, longissimus muscle area, percentage of trimmed four lean cuts and USDA carcass grade. In the frame size system, pigs with large frame size had less last rib backfat, less 10th rib fat depth, longer carcasses, higher percentage of four lean cuts and superior USDA carcass grades than pigs with small frame size did (P less than .05). The Bradley and Schumann test of sensitivity showed that selection by frame size was more sensitive than current USDA grade standards for discriminating feeder pig foreleg length, body depth and ham width. In addition, selection by frame size was more sensitive than current USDA grade standards for discriminating carcass length and carcass radius length. No increase in sensitivity (P greater than .10) was noted for carcass composition or growth traits over the current USDA Feeder Pig Grade Standards.  相似文献   

Spectral Properties of Near-Earth Asteroids: Evidence for Sources of Ordinary Chondrite Meteorites     

RP Binzel  SJ Bus  TH Burbine  JM Sunshine 《Science (New York, N.Y.)》1996,273(5277):946-948

Although ordinary chondrite (OC) meteorites dominate observed falls, the identification of near-Earth and main-belt asteroid sources has remained elusive. Telescopic measurements of 35 near-Earth asteroids ( approximately3 kilometers in diameter) revealed six that have visible wavelength spectra similar to laboratory spectra of OC meteorites. Near-Earth asteroids were found to have spectral properties that span the range between the previously separated domains of OC meteorites and the most common (S class) asteroids, suggesting a link. This range of spectral properties could arise through a diversity of mineralogies and regolith particle sizes, as well as through a time-dependent surface weathering process.  相似文献   

Expression Profile of Luteinizing Hormone Receptor Gene in Hierarchal Follicles and Regressing Oviduct Tissues of White Leghorn Hens During Moulting     

R Agarwal  KVH Sastry  V Tripathi  R Singh  R Saxena  J Mohan  RP Singh 《Reproduction in domestic animals》2013,48(2):278-283

In the present study, the expression profile of luteinizing hormone receptor (LHR) was investigated in the ovary, magnum and uterus and in hierarchcal follicles (F‐1, F‐2, F‐3 and F‐4) of hens subjected to moulting to establish their involvement in moulting and presence in non‐gonadal tissues. Fifty‐two layers (72 weeks) were subjected to moult for a period of 14 days. Four birds were sacrificed each time on 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12 and 14 days of moulting, and samples (ovary, magnum, uterus and hierarchal follicles) were collected aseptically for the quantitative study by real‐time polymerase chain reaction. The ovary, isthmus, uterus and magnum weight reduced significantly during induced moulting. From the 4 DOM, this reduction was drastic and reached approximately 80% of original weight in the case of ovary, isthmus and magnum and approximately 65% of original weight in the case of uterus on 14 DOM. Ovarian yellow follicles decreased gradually from 1 DOM to 4 DOM, after that no normal yellow follicle was observed in moulted bird. The number of atretic follicles increased gradually during the course of induced moulting, reaching the peak at 5 DOM. The LHR mRNA was detected in non‐gonadal tissues like magnum and uterus. The LHR expression was significantly (p < 0.05) down regulated in ovary, magnum and uterus throughout the treatment. These results indicated that LHR may have a role in reproductive tissue regression during moulting.  相似文献