Long-term Effects of Pyrethrin and Cyfluthrin, a Type II Synthetic Pyrethroid, Insecticide Applications on Bull Reproductive Parameters.

The objectives of this study were to determine effects of cyfluthrin and pyrethrin spray products, used in combination with cyfluthrin topical and ear tag applications, on bull reproductive parameters over 18 weeks. Angus or Angus x Simmental bulls were randomly assigned to one of three treatment groups: (i) no exposure to pyrethrins/cyfluthrin (CONT; n = 10), (ii) cyfluthrin ear tag and topical applications (ET; n = 10), or (iii) cyfluthrin ear tag, topical, premise spray and pyrethrin fog spray applications (ET+S; n = 8). Bull body weight was measured every 3 week, and body condition score and scrotal circumference were recorded on weeks 0, 9 and 18. Semen and serum were collected every 3 weeks for sperm evaluation and testosterone measurement, respectively. There was a treatment × week interaction (p < 0.01) for sperm with primary defects; bulls in CONT group had a greater (p = 0.01) percentage of sperm with primary defects than bulls treated with insecticides at week 18. Overall and progressive sperm motility, normal sperm morphology, secondary sperm defects and serum testosterone concentrations changed (p < 0.01) over time in all bulls; however, treatment did not affect (p ≥ 0.13) any of these parameters. There were also no treatment effects (p ≥ 0.08) on bull body weight, body condition score or scrotal circumference. The use of pyrethrin- and cyfluthrin-based insecticides, regardless of application, did not negatively affect reproductive parameters in beef bulls when administered over 18 weeks.

Effects of local anesthesia and flunixin meglumine on the acute cortisol response, behavior, and performance of young dairy calves undergoing surgical castration.

This study assessed the effects of flunixin meglumine (FM) and a local anesthetic block (LA) on postcastration performance, plasma cortisol concentration, and behavior in dairy calves. Thirty 2- to 3-mo-old Holstein-Friesian bull calves were allocated to 5 treatments: castration with LA (2% lidocaine injected into the testes and subcutaneously), castration with FM (1.1mg/kg, i.v.), castration with LA+FM, castration without drugs (CC), and sham castration (SC). Castration was performed using a Newberry knife and Henderson castrating tool. Feed intake and body weight gain were recorded for 10d postcastration. Plasma cortisol concentration and behavior frequency and duration were monitored for 8h postcastration. Variables with repeated measures were analyzed using PROC MIXED (SAS Institute Inc., Cary, NC); one-way ANOVA was used for nonrepeated measures. No differences in feed intake or body weight gain were detected among groups. Calves in the CC, LA, and FM groups had transient (<60, <60, and <45 min, respectively) increases in plasma cortisol concentration after castration, with a second increase at 120 min in the LA group, whereas cortisol concentration remained at baseline in the LA+FM and SC groups. Mean cortisol concentrations were lower for calves in the LA+FM and SC groups than in the CC group. The area under the plasma cortisol concentration curve during the first 3h postcastration was greater in CC- and LA-treated calves than in SC controls. Castration without drugs was associated with higher frequencies of crouching and statue standing and less oral activity compared with SC controls. Administering LA alone before castration was associated with higher frequencies of head turning, statue standing, and postural changes, and less feeding behavior compared with SC controls. More leg lifting to groom was seen in LA+FM-treated calves than in SC controls. Calves administered FM alone before castration exhibited less crouching than CC calves, fewer postural shifts, and more feeding behavior than LA-treated calves. In summary, FM alone tended to shorten the duration of cortisol response and reduce crouching after surgical castration. Combining LA+FM eliminated the cortisol response to castration but was associated with more leg lifting behavior. Treatment with LA alone did not mitigate the cortisol response and was associated with several behavioral differences compared with SC, FM-treated, or FM+LA-treated calves. Results suggest that LA alone did not effectively control discomfort in young dairy calves castrated using the Henderson castration tool.

Gene-centromere mapping of bovine DYA, DRB3, and PRL using secondary oocytes and first polar bodies: evidence for four-strand double crossovers between DYA and DRB3.

A genetic map consisting of three loci anchored at the centromere of bovine chromosome 23 was constructed by genotyping secondary oocytes (SO) and first polar bodies (PB1) using a polymerase chain reaction (PCR)-based approach. Primary oocytes arrested in prophase of meiosis I were stimulated in vitro to resume division and extrude PB1. Sixty SO and their matched PB1 were collected from 14 cows by micro-manipulation, subjected to amplification of the whole genome by primer extension preamplification, and genotyped independently for the linked genes PRL, DRB3, and DYA by PCR-RFLP analysis. Single-locus analysis of gene-centromere recombination rates were theta cen-DYA = 0.042, theta cen-DRB3 = 0.113, and theta cen-PRL = 0.166. The most likely order is cen-DYA-DRB3-PRL. Analysis of typing data from 3 cows revealed three meiotic divisions consistent with "linkage phase exchange" between DYA and DRB3 or PRL. One of the three linkage phase exchanges was confirmed by complementary genotypes in a matched secondary oocyte-first polar body pair. Such linkage phase exchanges could result from four-strand double crossovers between homologous chromosomes. Because all four gametes produced by four-strand double crossovers will be recombinant, more frequent occurrence of such events in females may explain the sexual dimorphism in genetic maps. Alternatively, four-strand crossovers could represent a type of recombination hotspot between DYA and DRB3, suggesting a mechanism for the high recombination frequency (15%) between these two class II genes of the bovine major histocompatibility complex.

Production of live offspring with predicted genotypes using PCR-RFLP analysis of polar bodies from mouse oocytes.

Accurate identification of genotypes in gametes and early embryos could facilitate the efficient production of offspring with desirable traits. This study demonstrates the feasibility of producing offspring with predictable genotypes from micromanipulated mouse oocytes. The Polymerase Chain Reaction (PCR) was used to amplify genes in the IA subregion of the major histocompatibility complex of the mouse. The validity of the approach was demonstrated in experiment 1 with IA haplotypes of unfertilized mouse ova amplified via PCR and distinguished by restriction fragment length polymorphism (RFLP) analysis. In experiment 2, fertilized oocytes were micromanipulated to remove the first and second polar bodies, which were then genotyped by validated PCR-RFLP procedures. Primary oocytes of heterozygous females contain two copies of each of the different alleles. Following meiosis I and II, the genotype of the ovum was predicted by subtracting the alleles observed in micromanipulated polar body samples. Sixty-two fertilized ova were micromanipulated and transferred to recipient females resulting in 27 live offspring (44%). The correct maternal contribution to the embryonic genotype was predicted in 19 of 27 (71%) offspring as confirmed by PCR-RFLP analysis of DNA from pup tails. Predicted genotypes of two pups were not confirmed (7%), whereas no prediction could be made in six cases (22%).

Multilocus analysis for gene-centromere mapping using first polar bodies and secondary oocytes.

Polar body and oocyte typing is a new technique for gene-centromere mapping and for generating female linkage maps. A maximum likelihood approach is presented for ordering multiple markers relative to the centromere and for estimating recombination frequencies between markers and between the centromere and marker loci. Three marker-centromere orders are possible for each pair of markers: two orders when the centromere flanks the two markers and one order when the centromere is flanked by the two markers. For each possible order, the likelihood was expressed as a function of recombination frequencies for two adjacent intervals. LOD score for recombination frequency between markers or between the centromere and a marker locus was derived based on the likelihood for each gene-centromere order. The methods developed herein provide a general solution to the problem of multilocus gene-centromere mapping that involves all theoretical crossover possibilities, including four-strand double crossovers.

Production of tissue inhibitor of metalloproteinases-1 by porcine follicular and luteal cells.

The objectives of the first experiment were to characterize the pattern of protein secretion by 1) porcine follicles before and after the preovulatory gonadotropin surge and 2) corpora lutea on d 4 and 11 after estrus (d 0 = estrus). Gilts were ovariectomized 1) on d 20 after estrus and before the preovulatory gonadotropin surge (pre-estrus group; n = 3), 2) 18 to 36 h after the onset of estrus and after the preovulatory gonadotropin surge (estrus group; n = 3), 3) on d 4 after estrus (n = 3), and 4) on d 11 after estrus (n = 4). Changes in pattern of protein secretion were determined by densitometric scanning of fluorographs. In the pre-estrus group, the major proteins secreted by follicular shells (FS) and granulosa cells (GC) had relative molecular masses (M(r)) of approximately 40,000, 46,000, and 55,000. In the estrus group (FS and GC), secretion of a M(r) 40,000 protein was decreased (P < .05) and secretion of a M(r) 30,000 protein was increased (P < .05) relative to the pre-estrus group. A predominant M(r) 30,000 protein was also secreted by corpora lutea on d 4 and 11. The objective of Exp. 2 was to determine whether synthesis of the M(r) 30,000 protein could be increased during the follicular phase by treatment with hCG, suggesting a role for the preovulatory gonadotropin surge in altering the pattern of protein secretion. Gilts were injected (i.m.) with saline (n = 3) or 500 IU of hCG (n = 3) on d 18 of the estrous cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of number of corpora lutea and fetuses on concentrations of progesterone in blood of goats.

The objectives of this study were to assess relationships between 1) number of corpora lutea (CL) and concentrations of progesterone (P) in plasma of goats from onset of estrus (d 0) to d 45 of pregnancy and 2) concentration of P and number of fetuses on d 45. Blood from 79 pregnant goats was obtained on d 0 and 1 and at 48-h intervals thereafter to d 25 of gestation. Additional samples were collected every 5 d from d 25 to d 45. Plasma samples were analyzed for P by RIA. Fetuses and CL were counted at laparotomy on d 45 +/- 3. Six does had one CL, 47 had two and 26 had three or four. Concentrations of P were compared for 1) animals with different numbers of CL and 2) animals with the same number of CL but different numbers of fetuses on d 45. Concentration of P increased in all animals from d 3 to a maximum of 8.5 +/- .3 ng/ml on d 13, then P declined to 5 +/- .3 ng/ml by d 35. Goats with multiple CL had higher P than goats with one CL (P less than .01) from d 7 to d 30. Of goats with two CL, those with two fetuses at d 45 had higher P on d 13 than those with one fetus (P less than .01). The number of CL or fetuses did not influence the concentration of P after d 30.

The transition from maternal to zygotic control of development occurs during the 4-cell stage in the domestic pig, Sus scrofa: quantitative and qualitative aspects of protein synthesis.

A study was conducted to identify the embryonic stage when the zygotic genome begins to direct development and to characterize protein synthesis in pig oocytes and embryos. Reproductive tracts of gilts were flushed to obtain unfertilized oocytes (UFO), zygotes (Z), 2-, 4-, and 8-cell embryos, compact morulae (M), initial blastocysts (IB), blastocysts (B), and hatched blastocysts (HB). Pig eggs and embryos were cultured in medium containing 1 microM L-[35S]methionine and evaluated for amino acid uptake, incorporation of the radiolabel into protein, and qualitative changes in protein profiles specific to each cleavage stage. Unfertilized oocytes sequestered 65.7 fmol methionine/4 h/embryo. Uptake of methionine decreased (p less than 0.05) from the Z (49.4), 2-cell (41.8), and 4-cell (37.6) embryonic stages to the M (8.97 fmol/4 h/embryo) stage. This downward trend was reversed at the IB, B, and HB stages when uptake increased to 37.3, 50.3, and 84.2 fmol/4 h/embryo, respectively. Incorporation of methionine into protein followed a similar pattern, being relatively higher in the UFO (21.0), Z (20.5), and 2-cell stages (16.0); decreased (p less than 0.05) at the 4-cell (6.67), 8-cell (6.84), and M (6.16) stages; and increased (p less than 0.05) at the IB (28.0), B (41.5), and HB (69.6 fmol/4 h/embryo) stages. Differences in protein profiles were observed for UFO, Z, 4-cell, and M stages using lysates of single embryos, one-dimensional SDS-PAGE, and fluorography.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of initial length of uterus per embryo on fetal survival and development in the pig.

Influence of initial length of uterus available to each embryo on its subsequent survival and development was determined by systematic restriction of the length available to each potential embryo. Fifty-seven pregnant crossbred gilts were laparotomized at d 3 of gestation, length of uterine horns was measured in situ and corpora lutea (CL) were counted. In Exp. 1, uterine space available to each potential embryo was restricted by ligating one uterine horn 5 cm from the tip per CL. Uteri were examined at d 20, 25 or 50. In Exp. 2, one uterine horn was ligated on d 3 at 10, 20 or 30 cm from the tip per CL and uteri were examined at d 50. Embryos in the restricted section (RS) had a specific mean uterine length available to each potential embryo of 5, 10, 20 or 30 cm. Embryos in the nonrestricted section (NRS) had a variable mean uterine length available to each potential embryo of 44 +/- 4 cm. When embryos were restricted to 5 cm, the proportion of surviving fetuses at d 20, 25 and 50 was 61, 12 and 8%, respectively, whereas in combined NRS it was 82%. When the uterus was examined at d 50 after restricting embryos to 10, 20 or 30 cm/CL, 25, 33 and 52% of fetuses survived; in combined NRS survival was 71%. Each fetus surviving to d 50 in RS was associated with 36 cm of initial uterine length but fetal survival was not associated with number of CL. In RS, 59% were female fetuses and in NRS 50% were females.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth characteristics, protein synthesis, and protein degradation in muscles from fast and slow-growing chickens.

Developmental changes in muscle growth were studied in Single Comb White Leghorn (SCWL) and broiler-type (B) chickens. The extensor digiti communus (EDC) and ulnaris lateralis (UL) muscles were chosen for study because these muscles can be maintained in vitro, permitting the direct measurement of the fractional rate of protein synthesis (FSR) and the fractional rate of degradation (FDR). These muscles were removed from chicks at 1, 5, 10, and 20 days of age. Muscles for B were heavier, grew at a faster rate, and had greater fractional rates of growth than muscles from SCWL. Muscle protein concentrations were similar for SCWL and B. The deoxyribonucleic acid (DNA) concentrations were greater in EDC muscles from SCWL than B at all time periods. Concentrations of DNA were greater in UL muscles from SCWL than B after Day 1. The FSR and FDR were measured in muscles incubated in vitro. At 9 days of age, FSR in broiler and SCWL chicks was not significantly different in either muscle. The FDR was 12 and 19% lower in broiler EDC and UL muscles, respectively, demonstrating that broiler EDC and UL muscles accrete protein at a greater rate and more efficiently than SCWL muscles because of a slower rate of protein degradation. The FSR and FDR were also compared in B and SCWL chicks of 8 and 11 days, respectively, with equal DNA unit sizes. The FSR in B was 27 and 13% greater in EDC and UL muscles, respectively, demonstrating that protein synthesis per nucleus is greater in B chicks.

Regulation of protein degradation in chick muscle by several hormones and metabolites.

Experiments were conducted to examine the effect of various regulatory agents on the rate of protein degradation in chick extensor digiti communis (EDC), and ulnaris lateralis (UL) muscles in vitro. Muscles were incubated in an oxygenated Krebs-Ringer bicarbonate buffer. Rates of protein degradation were calculated from the rate at which tyrosine was released from protein. Protein synthesis was blocked with cycloheximide to prevent reutilization of tyrosine. Insulin (bovine) decreased protein degradation in the EDC and UL muscles by 11.3 and 10.5%, respectively, when glucose was present in the incubation medium and by 11.0 and 10.3% when glucose was omitted. This suggested the action of insulin on protein degradation was not secondary to effects on glucose transport. Glucose alone decreased protein degradation by 17.3 and 14.8% in EDC and UL, respectively. Glucagon (bovine), cortisol, corticosterone, and dexamethasone did not have significant effects on the rate of protein degradation in either muscle. Branched chain amino acids (BCAA) decreased the rate of protein degradation by 21.6% in the presence of insulin but did not significantly change the rate when insulin was omitted. These results demonstrate that chicken muscle, like that of rats, responds to insulin, glucose, and BCAA by decreasing protein degradative rates. The rates of protein degradation in three muscles, EDC, UL, and extensor digitorum longus (EDL), were compared utilizing a medium containing insulin, glucose, and BCAA to minimize protein degradation. All three muscles released tyrosine at a linear rate for 2.25 hr of incubation. The rate of protein degradation in the slowest growing EDC muscle was significantly greater than that in the UL, whereas the fastest growing EDL had the slowest rate of protein degradation.

Mapping of the gene for G blood group antigens to chromosome 15 in swine.

Linkage analysis between size variants of the centromeric region of chromosome 15 and G blood group alleles produced a lod score of 5.03. The maximum likelihood estimate of the recombination fraction is theta = 0.24 with a 95% confidence interval of 0.08 less than theta less than 0.40. Since this is the second time that linkage between a chromosome 15 marker and the G blood group locus has been shown, the assignment of the G blood group locus to chromosome 15 is confirmed.