Production of Lambs After the Transfer of Fresh and Cryopreserved in vitro Produced Embryos from Prepubertal Lamb Oocytes and Unsorted and Sex-sorted Frozen-thawed Spermatozoa

Cumulus-oocyte complexes from hormone-stimulated 3-4-week-old (n=43) and 6-7-week-old (n=12) prepubertal lambs were matured in vitro and incubated with unsorted, or X- or Y-spermatozoa separated with a high-speed cell sorter (SX MoFlo)frozen-thawed. Presumptive zygotes were then cultured to the blastocyst stage, and transferred to recipients fresh or after cryopreservation (frozen). Oocyte cleavage was higher (p <0.05) with unsorted (515/926, 55.6%) than X- or Y-spermatozoa (261/672, 38.8% and 229/651, 35.2%, respectively) and blastocyst formation (% zygotes) by Day 9 of in vitro culture was lower (p <0.05) for X- (102/261, 39.1%) than unsorted spermatozoa (249/515, 48.3%), but did not differ between Y-spermatozoa (103/229, 45.0%) and unsorted spermatozoa, or between X- and Y-spermatozoa (p >0.05). For fresh embryos, survival to term was 50.0% (3/6) for unsorted, 0.0% (0/6) for X- and 16.7% (1/6) for Y-spermatozoa-derived embryos (p >0.05), and for frozen embryos was 4.0% (2/50) for unsorted, 9.1% (2/22) for X- and 2.9% (1/34) Y-spermatozoa-derived embryos (p >0.05). Of the two lambs born from X-spermatozoa-derived embryos, one was female (50%), and from the two Y-spermatozoa-derived lambs, both were male (100%), demonstrating that lambs can be produced after the transfer of fresh and cryopreserved IVP embryos derived from prepubertal lamb oocytes and frozen-thawed sex-sorted sperm.     

Effect of pavetamine on protein synthesis in rat tissue

Pavetamine, the active principle of plants causing gousiekte in ruminants, was found in this study to be an inhibitor of protein synthesis in the rat heart. Sprague-Dawley rats were injected intra-peritoneally with 8-10 mg/kg pavetamine and the levels of protein synthesis in different organs determined utilizing L-[4-3H]phenylalanine incorporation. In contrast to the more than 23% inhibition found in heart tissue at 4, 24 and 48 h after administration of pavetamine, the effect on the kidney, liver, spleen, intestine and skeletal muscle was minimal or returned to pretreatment levels within 48 h. These results may offer an explanation for the clinical signs observed in ruminants with gousiekte, where the heart only is affected.     

Myxozoans infecting the sharptooth catfish, Clarias gariepinus in the Okavango River and Delta, Botswana, including descriptions of two new species, Henneguya samochimensis sp. n. and Myxobolus gariepinus sp. n

During a recent investigation of parasites infecting fishes from the Okavango River and Delta, Botswana (southern Africa) fourteen sharptooth catfish, Clarias gariepinus (Burchell, 1822) (Siluriformes: Clariidae) were examined for the presence of myxozoan infections. Results revealed the presence of two species of the genus Henneguya Thélohan, 1895 and one species of the genus Myxobolus Bütschli, 1882 infecting this fish host. Two of the sampled fish exhibited large plasmodia of Henneguya suprabranchiae Landsberg, 1987 in the cartilage of the accessory breathing organ, another two individuals were infected with H. samochimensis sp. n. plasmodia in the gills and another three individuals revealed an infection with Myxobolus gariepinus sp. n. plasmodia in the ovaries.     

Research note: Maize and forage sorghum as silage crops under drought conditions

Abstract

Maize (Senkuil) and a forage sorghum hybrid (DeKalb FS2) were compared as silage crops under drought conditions. Sorghum yielded more digestible organic matter per hectare than maize. Maize and forage sorghum silage were well preserved and stable under aerobic conditions.     

Device Applications of Side-Chain Ferroelectric Liquid Crystalline Polymer Films

Side-chain ferroelectric liquid crystalline polymers are currently used in a number of applications, including displays and electrical sensors. Comparisons with existing technologies and materials indicate that relative to ceramics, such polymers have lower figures of merit but offer greater durability in sensor applications.     

The effect of a monensin ruminal delivery device on performance of cattle grazing pasture

A total of 28 trials utilizing 2,262 steers and heifers were conducted to evaluate a sustained monensin2 ruminal delivery device (RDD) on the daily gain of grazing cattle. Five series of trials, with four to eight trials per series within a grazing season, were conducted to evaluate the daily gain response under different environmental conditions and locations. Pastures grazed included both summer (cool- and warm-season grasses and native range) and winter (rye, ryegrass and wheat) growing pastures. The experimental design for all trials in each of five series was a randomized complete block with initial weight or breed as the blocking factor. The treatments compared in series I, III, IV and V (20 trials) were a control and a single RDD, whereas in series II (eight trials), a 2 x 2 factorial was utilized that compared RDD and estradiol 17-beta controlled release implants. In the five series of trials, the monensin RDD increased daily gain .04 (P = .002), .03 (P = .07), .09 (P = .01), .05 (P = .10) and .08 kg (P = .04) compared with the controls. Use of the RDD provided an effective method of achieving consistent monensin delivery and weight gain improvement without requiring the extra labor needed to administer monensin via hand-feeding or self-feeding supplements, blocks or loose mineral.