Direct radioimmunoassay of progesterone in mare plasma

A rapid and low cost radioimmunologic procedure for progesterone assay in mare plasma is proposed. Radioimmunoassay is performed directly on 10 microliter of unextracted plasma. Free progesterone is adsorbed on dextran-charcoal, then the aqueous phase is decanted and extracted by 1 ml of scintillation fluid. Counting is performed directly on this two-phase system. Results are comparable to those obtained with radioimmunoassays using extracted plasma.     

Direct radioimmunoassay of progesterone in rat serum

A direct method has been described which makes possible a specific assay of progesterone in rat serum without extraction. Anti-progesterone serum was prepared in our laboratory by the immunization of three rabbits with 4-pregnen-3, 20-dione-3 CMO:BSA. This antiserum (Gunma OGP#1) displayed little or no cross reaction with 20 alpha-dihydroprogesterone (0.38%), pregnenolone (0.44%), 17 alpha hydroxypregnenolone (less than 0.1%), 20 beta hydroxyprogesterone (2.4%), 17 alpha hydroxyprogesterone (2.88%) or deoxycorticosterone (2.19%). The nonspecific inhibitory effect of serum was compensated for by adding progesterone-free serum to the standard curve tubes. The sensitivity of this assay was 1.1 pg/tube and serum progesterone could be measured by using as little as 1 microliter of serum. The working range of the standard curve was 1.25-2560 ng/ml. Under the conditions of this assay (1 microliter of serum per tube), interference from steroid binding proteins did not affect the sensitivity, precision or reliability of the assay. The intra-assay and inter-assay coefficients of variation were 5.5% and 8.7%, respectively, and the assay values correlated well with those obtained by the extraction method (R = 0.997, P less than 0.001). Analytical recovery indicates a close correlation between added and recovered progesterone concentrations (R = 0.992, P less than 0.001), and the recovery rate averaged 96%. Compared with the extraction method, the direct progesterone assay has the advantage of speed, precision and simplicity. The method described is particularly suitable for routine assays of progesterone in rat serum.     

Direct radioimmunoassay of progesterone in milk using a radioiodinated progesterone derivative

A heterologous radioimmunoassay technique which allows the measurement of progesterone in whole milk, without extraction is described. An antiserum against progesterone-12α-succinyl-BSA and progesterone-11α-(2′-methyl)succinyl-¹²⁵I-thyramine was used. When applied in pregnancy detection on day 20–22, progesterone levels of up to 6 ng/ml or above 8 ng/ml were indicative of an unsuccessful or a successful insemination, respectively.The sensitivity of the assay was 0.8 ng/ml, and the values found in cow milk ranged from 0.8 to 50 ng/ml.     

A solid-phase radioimmunoassay for plasma progesterone

A detailed procedure is presented for the assay of plasma progesterone. The routine assay is based on the use of antiserum which is covalently linked to microcrystalline cellulose, the double-antibody method being used as a reference separation system. This procedure gives high precision accompanied by small and acceptable losses of antiserum titre but without loss of sensitivity when compared with the double-antibody method. Ethanol is first added to the plasma (10vol. of plasma+1vol. of ethanol) after which a single extraction with light petroleum yields a constant recovery [92.4+/-1.2 (s.d.)% of added [(3)H]progesterone] and obviates the need for tracer recoveries on each sample being assayed. Distortions of the response curve owing to solvent residues have been almost eliminated. The assay can measure progesterone at all stages of the menstrual cycle when volumes of 200mul of plasma are used and this permits the detection of the periovulatory rise at its inception. Detailed specificity studies are presented for the assay end point itself and these are related to the responses to be expected in extracts of plasma. Progesterone-like activity was found in urine and a fourfold increase in excretion rates was observed between the follicular and luteal phase of the normal menstrual cycle.     

Comparative mapping in farm animals.

This paper summarises the current status of comparative mapping in farm animals. For most of the major farm animal species, a wide range of genomic tools are now available to create high-resolution genetic and physical maps of the genome. For many farm animals, the use of radiation hybrid panels and sequence data from expressed sequence tag (EST) projects has accelerated the development of high-resolution comparative maps, with human--the model species for farm animals. These tools and comparative maps are being used to map and identify the genes at the loci for simple and complex traits. The development of detailed physical maps in farm animals based on radiation hybrid panels and bacterial artificial chromosome (BAC) contigs provides a direct link between the 'information-poor' maps of farm animals and the 'information-rich' genomes of human and other model organisms.     

Survey of aflatoxicosis in farm animals.

Over a 22-month period, 278 submissions of farm animals were made to the North Carolina Diagnostic Laboratory for suspected aflatoxicosis, and 94 cases were confirmed on the basis of finding aflatoxin in the feed and the occurrence of bile ductule proliferation. There was an annual variation in the incidence of aflatoxicosis, as well as a seasonal variation: the peak incidence occurred in the winter, and the minimum incidence occurred during the summer. The annual increase coincided with the corn harvest. All confirmed cases occurred on farms that raised and stored their own corn, and 88% were in swine. The cases were geographically localized in the eastern section of North Carolina (94% of the total cases) where 82% of the swine and 79% of the corn are produced. Mean concentration of aflatoxin in feed samples from the confirmed cases was 3,890 mug/kg, and the mean value for corn used in making the feed was 5,180 mug/kg. Only aflatoxin B1 was found in the samples. These data were interpreted to mean that the incidence and severity of aflatoxicosis is greater than previously suspected, that poor on-farm storage of corn is a primary contributing factor, that aflatoxin formation continues during and after the milling process, and that mycotoxicoses other than aflatoxicosis may cause equal or greater problems.     

A radioimmunoassay for'plasma progesterone

A radioimmunoassay for progesterone was developed which uses one micro-column chromatography for purification of hexane extracts of plasma.     

MicroRNAs in farm animals

MicroRNAs (miRNAs) are a class of ∼22 nucleotide-long small noncoding RNAs that target mRNAs for translational repression or degradation. miRNAs target mRNAs by base-pairing with the 3′-untranslated regions (3′-UTRs) of mRNAs. miRNAs are present in various species, from animals to plants. In this review, we summarize the identification, expression, and function of miRNAs in four important farm animal species: cattle, chicken, pig and sheep. In each of these species, hundreds of miRNAs have been identified through homology search, small RNA cloning and next generation sequencing. Real-time RT-PCR and microarray experiments reveal that many miRNAs are expressed in a tissue-specific or spatiotemporal-specific manner in farm animals. Limited functional studies suggest that miRNAs have important roles in muscle development and hypertrophy, adipose tissue growth, oocyte maturation and early embryonic development in farm animals. Increasing evidence suggests that single-nucleotide polymorphisms in miRNA target sites or miRNA gene promoters may contribute to variation in production or health traits in farm animals.     

Giardia infection in farm animals

Giardia infection is prevalent in farm animals from an early age. Despite the wide occurrence of the infection and recent understanding of its epidemiology, many aspects of giardiasis of farm animals remain unclear. In this article, Lihua Xiao discusses the prevalence, patterns, sources and clinical importance of Giardia infection in a variety of farm animals.     

Control of ovulation in farm animals

Examination of hormonal changes occurring in farm species at the onset of puberty, during the follicular phase of the oestrous cycle, and at those times when ovarian activity is re-established after periods of seasonal or lactational anoestrus, provides circumstantial evidence that the final phases of follicular development are dependent on a pattern of tonic (episodic) LH secretion. A suppression of episodic LH secretion is associated with periods of anovulation. Stimulation of tonic LH secretion by repeated injections of small doses of synthetic Gn-RH or purified LH restores normal reproductive function in all but deeply anoestrous animals. Continuous infusion of Gn-RH is as effective as repeated injections. It is suggested that an additional inadequacy, possibly endocrine, contributes to the anovulatory state in deep anoestrus.     

Lice of farm animals in Libya

Abstract. This first report on the lice of farm animals in Libya lists a total of fifteen species, as follows: Haematopinus quadripertusus and Linognathus vituli from cattle, Bovicola ovis, Linognathus pedalis, L.afrlcanus and L.ovillus from sheep, L.stenopsis, L.africanus and Bovicola caprae from goats. Poultry harboured Lipeurus caponis, L.heterographus, Menacanthus stramineus, Menopon gallinae, Goniocotes gallinae, Goniodes gigas and G.dissimilis.