Ultrasonographic characteristics of the preovulatory follicle preceding and during ovulation in mares

Changes in appearance of preovulatory follicles were observed with real-time ultrasonography prior to and during ovulation in mares. Preovulatory follicles of 15 mares were scanned at < 1 hr intervals for 12 hr or more frequently if displaying signs of impending ovulation. If ovulation was not imminent at the end of 12 hr (n = 2), mares were removed from the trial. Mean follicular diameter decreased 13% from 30 minutes prior to ovulation until the beginning of ovulation. Fifteen to 77 minutes (mean = 41 min) prior to ovulation, a break in or a protrusion of the follicular wall toward the ovulation fossa was visualized in all follicles and was a consistent indicator of impending ovulation. A rapid decrease in size of follicles (ovulation) occurred within a period of 5 to 90 seconds (mean = 42 sec). Little or no fluid remained in the antrum following ovulation. An increase in echogenicity (whiteness) of the follicular wall and echogenic “spots” within the follicle were frequently visualized (13/13, 100% and 7/13, 54% respectively) prior to ovulation; however, prediction of time of ovulation could not be based solely on these individual changes.     

Comparison of HCG, buserelin and luprostiol for induction of ovulation in cycling mares

Sixty nonlactating light-horse mares were used to compare the efficacy of hCG, buserelin (a GnRH analog) and luprostiol (a PGF₂α analog) for induction of ovulation in cycling mares. Mares were assigned to 1 of 4 treatments: 1) controls; 2) 40 μg buserelin IM at 12 hr intervals during estrus until ovulation; 3) 7.5 mg IM luprostiol; and 4) 3,300 IU hCG. Treatments were given once a mare obtained a ≥35mm follicle and had been in estrus ≥2 days. Both buserelin and hCG shortened (p<0.05) the interval from treatment to ovulation compared to controls; whereas, luprostiol failed to hasten ovulation. Number of follicles ovulated was similar among all 4 groups. Although buserelin and hCG were equal in their ability to induce ovulation, an average of 3.8 injections of buserelin was required for hastening of ovulation.     

Growth and survival of selected aquatic animals in two saline groundwater evaporation basins: an Australian case study

Evaluation trials were undertaken in two evaporation basins filled with saline groundwater to identify finfish and shellfish that have the potential to survive and grow in these conditions. Test animals were reared in replicate culture units in each of two basins filled with saline groundwater located in the Goulburn–Murray Irrigation District (GMID), south‐eastern Australia. Salinity in basin 2 (9.5–24.6 p.p.t., mean 16.8 p.p.t.) was significantly higher than in basin 1 (8.8–15.2 p.p.t., mean 11.6 p.p.t.). Some differences were observed between the ionic concentrations in the groundwater and sea water (at 10 p.p.t.) and may have affected growth and survival of some species. Survival and growth for oysters (Crassostrea gigas and Saccostrea glomerata) in the basins were low. Shrimps (Penaeus monodon and Marsupenaeus japonicus) did not survive beyond 3 weeks. Of the eight species of fish stocked into the basins, Salmo salar, Macquaria novemaculeata and Acanthopagrus butcheri survived and grew in both basins. Oncorhynchus mykiss did not survive in the low‐salinity basin, whereas Bidyanus bidyanus did not survive in the high‐salinity basin. These results indicate that some species of fish in particular can be cultured in saline groundwaters within the GMID.     

Release of ferulic acid from oat hulls by Aspergillus ferulic acid esterase and trichoderma xylanase

Oat hulls, an agricultural byproduct, contain a relatively high amount of ferulic acid (FA; 4-hydroxy-3-methoxycinnamic acid), which is believed to be inhibitory to oat hull biodegradability by rumen microorganisms. In this paper, Aspergillus ferulic acid esterase (FAE) was investigated for its ability to release FA from oat hulls. The objectives were to determine the effects of particle size of oat hulls (ground to pass through 1 mm and 250 microm screens and a 100 microm sieve) on release of FA by FAE both in the presence and in the absence of Trichoderma xylanase. The results show that the release of FA by FAE was dependent upon the particle size of oat hulls (< or = 250 microm). In the absence of Trichoderma xylanase, little FA was released by FAE. In the presence of Trichoderma xylanase, there was a significant release of FA by FAE, indicating a synergistic interaction between FAE and Trichoderma xylanase on release of FA from oat hulls. These results indicate that FAE is able to break the ester linkage between FA and the attached sugar, releasing FA from oat hulls. This may leave the remainder of the polysaccharides open for further hydrolytic attack by rumen microorganisms. It is likely that removing FA from oat hulls could improve rumen biodegradability, thus improving the nutritional value of oat hulls.     

Laminitis-like changes in the claws of feedlot cattle

The purpose of this study was to observe and quantitate changes in the claws of two groups of feedlot cattle (calves and backgrounded yearlings) fed diets that varied in energy (73.5 or 78.5% TDN) and crude protein (11, 13, 15, 16, 17, or 19%) content. At slaughter, the thickness of sole horn and the prevalence of toe and heel hemorrhages were greater in calves than in yearlings (p<0.02). Feeding the high-energy ration increased the prevalence of toe and heel hemorrhages in calves (p<0.02) and heel hemorrhages in yearlings (p<0.02). In yearlings, rotation of the distal phalanx and ridging of the dorsal wall of the claw were the most prominent pathological features. Osteopathy of the apex of the distal phalanx occurred more frequently in calves than in yearlings (p<0.01). This study suggests that intensive feeding of beef cattle before they reach 14 months of age has a deleterious effect on digital health.     

大豆皮替代奶牛日粮中玉米与小麦麸对瘤胃干物质与纤维消化的影响

采用尼龙袋消化试验研究大豆皮替代奶牛日粮中玉米与小麦麸对瘤胃干物质与纤维消化特性的影响,试验处理为大豆皮分别替代精料中0（对照）,25％,50％,75％和100％玉米与小麦麸的5个替代水平的产奶牛饲粮,饲粮的精料和粗料比为50：50,利用2头装有永久性瘤胃瘘管的本地黄牛测定5种大豆皮替代水平饲粮的干物质（DM）和中性洗涤纤维（NDF）的尼龙袋消化率与动态消化参数。所用数学模型为：Y＝a b(1-e^-c(t-L)。大豆皮DM与NDF的每小时消化速度分别为0．072和0．063,DM和NDF中潜在可消化组分比例（a b)分别为925和89％,提高大豆皮替代水平,饲粮DM中慢速消化组分b直线提高（P＝0．023）,快速消化组分a趋于下降（P＝0．140）,消化延滞期趋于延长（P＝．0127）.提高大豆皮替代水平,对饲粮DM中其他动态消化参数没有影响（P＝0．360－0．903）。随着大豆皮替代玉米与小麦麸水平的提高,饲粮NDF中慢速消化组分的比例b,潜在可消化组分（a b)呈二次曲线规律提高（P＝0．001－0．006）,快速消化组分a的比例趋于线性提高（P＝0．082）,而慢速消化组的消化速度c不受大豆皮替代水平的影响（P＝0．688）。从本试验得出结论：以大豆皮替代奶牛饲粮中0,25％,50％,75％和100％的玉米与小麦麸,对饲粮干物质潜在可消化组分比例和消化速度无明显影响,但对纤维消化具有促进作用。     

Evaluation of wheat-based thin stillage as a water source for growing and finishing beef cattle.

Two trials were conducted to evaluate the nutritional value of wheat-based thin stillage as a water source for cattle. In Trial 1, 20 large-framed steers were fed a basal diet based primarily on barley grain and barley silage, with ad libitum access to water or thin stillage at one of three DM concentrations (2, 4, and 6.7%) in a completely randomized design. The trial consisted of a 70-d growing period and a finishing phase. In Trial 2, total-tract nutrient digestibility coefficients of the basal diet and water treatments fed in the growing period were determined in a randomized complete block design using 12 medium-framed steers. The results showed that when only DMI from the basal diet was considered, there was a linear reduction (P<.01) in DMI and a linear improvement (P<.01) in the gain:feed ratio with no effect on daily gain as thin stillage DM concentration increased. No differences were detected in DMI or efficiency of gain when total DMI (basal diet and thin stillage) was considered. Carcass traits indicated a trend toward increased (P<.06) carcass fat with increasing thin stillage DM concentration. Results of Trial 2 indicated a linear improvement (P<.05) in apparent digestibility of DM, CP, NDF, and energy of the total diet (basal diet and thin stillage) as thin stillage DM concentration increased. We concluded that supplementing growing and finishing cattle with thin stillage reduced the amount of the basal diet required for gain and improved nutrient utilization.     

Control of Gene Expression for the Genetic Engineering of Cereal Quality

The recent success of techniques for the direct transfer of individual genes to cereal species suggests that specific modifications to grain end-use properties will be achievable in the near future. The suitability of direct gene transfer to the problem, the choice of the promoter and transformation strategy need to be considered before attempting such modifications. This review discusses these questions with reference to current knowledge of seed-specific and, in particular, endosperm-specific and abscisic acid-responsive gene promoters. This perspective is of special importance in attempts to engineer cereal proteins.     

Heterogenous and xenogenous fertilization of in vivo matured equine oocytes

Forty-five in vivo matured equine oocytes were recovered from 63 follicular aspiration attempts (71.4%). HCG did not improve recovery rate (65% — 24/37 for treated vs 81% — 21/26 for nontreated mares). Fifteen oocytes were transferred into the oviduct of inseminated recipient mares (heterogenous fertilization) and 15 oocytes plus equine spermatozoa were transferred into rabbit oviducts (xenogenous fertilization). Ten oocytes (3 fertilized) were recovered from recipient mare oviducts following removal and flushing two days after transfer. Eight oocytes (nonfertilized) were recovered from rabbit oviducts. Oviductal transfer into separate recipient mares of three embryos produced from heterogenous fertilization resulted in two pregnancies. One mare produced a normal live foal and the other mare aborted at 20 days of gestation. Results from these studies suggest that: 1) a reliable method for collection of in vivo matured oocytes has been established, and 2) heterogenous fertilization is a technique that with refinement should be immediately applicable to obtain foals from valuable infertile mares that fail to get pregnant or produce embryos by standard methods.