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Determination of the optimal insemination time in dairy cows is vital for fertilization success and is a challenging task due to silent or weak signs of estrus shown by some cows. This can be overcome by combining several estrus detection methods, leading to higher detection rates. However, an efficient, noninvasive method for detecting estrus in cows is still needed. Chemical cues released by the cow during estrus have been proposed to have pheromonal properties and signal readiness to mate to the bull. Such cues could be used in an industrial setting to detect cows in estrus. However, no conclusive published data show temporal changes in putative sex pheromone levels during estrus. The goal of this study was to determine the temporal pattern of putative sex pheromone components during estrus and to assess the reproducibility of changes in pheromone concentration with respect to ovulation time. Two injections of the hormone PGF 2α were administered over a 2-wk interval to induce and synchronize the estrous cycles of 6 Holstein cows. The precise time of ovulation was determined by means of an ultrasound technique, and estrus was determined by visual observation. Using solid-phase microextraction gas chromatography-mass spectrometry techniques, we showed that acetic and propionic acids, which have been proposed to be putative sex pheromone components in cows, were present in the headspaces of all estrous and diestrous fecal samples, whereas 1-iodoundecane was not detected by solid-phase microextraction or by solvent extraction with diethyl ether. Low levels of acids were observed until 1 d before ovulation, at which point their concentrations increased, peaking around 0.5 d before ovulation. The application of labeled synthetic standards revealed that during the peak of release, 36 ± 8 ng (average ± SD) of acetic acid and 10 ± 3 ng of propionic acid were present in 0.5-g samples of estrous-phase fecal matter compared with 19 ± 5 and 2.3 ± 1 ng of acetic and propionic acids, respectively, in the control diestrous samples. After the peak, the amounts of the compounds decreased sharply to match those of the control samples and afterward returned to the baseline readings. This decrease in the amounts of putative pheromone components was registered about 12 h before ovulation, indicating that acetic and propionic acids could be used as biomarkers for the electronic detection of ovulation., (Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Analysis of the sex pheromone gland of virgin Synanthedon scoliaeformis females by gas chromatography/mass spectrometry revealed six compounds structurally related to sex pheromone components of other clearwing moths: (E,Z)-2,13-octadecadienyl acetate (E2,Z13-18:OAc), (E,Z)-2,13-octadecadienol, octadecanol acetate, octadecanol, (Z,Z)-3,13-octadecadienyl acetate (Z3,Z13-18:OAc), and (Z)-13-octadecenyl acetate. Trapping tests demonstrated that E2,Z13-18:OAc is the sex pheromone of S. scoliaeformis and is essential for attracting males; addition of the other compounds did not enhance catch. Synanthedon scoliaeformis and S. tipuliformis are the only Palearctic clearwing moths whose distribution range and seasonal flight periods overlap and that are known to use E2,Z13-18:OAc in sex pheromonal communication. Hourly monitoring of male catches in traps revealed that sex pheromone communication in S. scoliaeformis and S. tipuliformis species follows different diurnal patterns. Z3,Z13-18:OAc, found in S. scoliaeformis females, is a known behavioral antagonist against S. tipuliformis males, while (E,Z)-3,13-octadecadienyl acetate, a minor sex pheromone component of S. tipuliformis, is an antagonist against S. scoliaeformis males. The effect of sex pheromones and antagonists, combined with different diurnal mate searching times, contribute to the specificity of sex communication channels in these two clearwing moth species.

Previously it was shown that m- and p-cresols in the urine of mares exhibits a temporally reproducible pattern that is dependent on ovarian activity and, thus, provides information about the timing of ovulation. New behavioral data demonstrate 1) that stallions spend significantly more time sniffing p-cresol as compared to o-, and m-cresols, and, 2) that the extent of stallions' erections differ significantly in response to different types of samples. The lowest erection level was recorded for the pure-water control, a moderate erection level was elicited by the urine of diestrous mares, and the highest erection level was elicited by urine of a diestrous mare containing synthetic p-cresol at a quantity equivalent to half of the amount of p-cresol found in the urine of estrous mares. Consequently, p-cresol is at least one of the components of a horse sex pheromone.

The four possible isomers of tetradeca-4,8-dien-1-yl acetate and corresponding alcohols were synthesized stereoselectively by synthetic routes employing Wittig coupling reaction for the preparation of (Z,E)- and (Z,Z)-isomers, and alkylation of terminal alkynes for the preparation of (E,E)- and (E,Z)-isomers as the key steps. Synthetic products were characterized by 13C- and 1H-NMR spectroscopy as well as mass-spectrometric methods. All four isomers gave distinctive mass spectra where m/z 81 fragments clearly dominated. Elution order, followed by retention index presented in parenthesis, of tetradeca-4,8-dien-1-ols was determined as (Z,Z) (2082.1), (Z,E) (2082.8), (E,E) (2083.1), and (E,Z) (2083.2) from unpolar SPB-1 column, and as (E,E) (2210.2), (Z,E) (2222.1), (E,Z) (2223.4), and (Z,Z) (2224.7) from polar DB-WAX column. The isomers of tetradeca-4,8-dien-1-yl acetates eluted in the order of (Z,Z) (2176.1), (Z,E) (2178.4), (E,Z) (2185.9), and (E,E) (2186.4) from SPB-1, and (Z,E) (2124.3), (E,E) (2157.7), (Z,Z) (2128.9), and (E,Z) (2135.9) from DB-WAX columns. Field-screening tests for attractiveness of tetradeca-4,8-dien-1-yl acetates revealed that (4Z,8E)-tetradeca-4,8-dien-1-yl acetate significantly attracted Phyllonorycter coryli and Chrysoesthia drurella males. (4E,8E)-Tetradeca-4,8-dien-1-yl acetate was the most efficient attractant for Ph. esperella and Ph. saportella males, and (4E,8Z)-tetradeca-4,8-dien-1-yl acetate was attractive to Ph. cerasicolella males.