Effect of day of the estrous cycle at the initiation of a timed artificial insemination protocol on reproductive responses in dairy heifers

Our objectives were to identify stages of the estrous cycle at which initiation of a timed artificial insemination (Ovsynch/TAI) protocol may reduce pregnancy rates and to monitor ovarian follicle dynamics and corpus luteum development after initiation of the Ovsynch/TAI protocol at different stages of the cycle. Cycling Holstein heifers (n = 24) were injected twice with prostaglandin F2alpha to induce estrus and were scanned by ovarian ultrasonography to determine the day of ovulation (d 0). Heifers were assigned to initiate the Ovsynch/TAI protocol at d 2 (n = 5), 5 (n = 5), 10 (n = 4), 15 (n = 5), or 18 (n = 5) of the cycle. The Ovsynch/TAI was initiated with an injection of gonadotropin-releasing hormone agonist followed 7 d later with an injection of prostaglandin F2alpha. At 36 h after injection of prostaglandin F2alpha, heifers were injected with gonadotropin-releasing hormone agonist and inseminated 16 h later. Heifers were scanned daily during the Ovsynch/TAI protocol and every other day after insemination until 16 d later. Blood samples were collected daily starting at the 1st day heifers were scanned and continued until 16 d after insemination. Initiation of the Ovsynch/TAI protocol at d 15 of the estrous cycle caused heifers to ovulate prior to insemination. A shortened return to estrus (< 16 d) was caused by ovulation failure to the second gonadotropin-releasing hormone injection, by incomplete regression of the corpus luteum, and by short life-span of the induced corpus luteum. Day of the cycle in which the Ovsynch/TAI protocol is initiated affects dynamics of follicular development, plasma progesterone profiles, and occurrence of premature ovulation. Size of the pre-ovulatory follicle was associated positively with subsequent progesterone concentrations following insemination.     

Follicular Dynamics in Heifers during Pre-pubertal and Pubertal Period Kept under Two Levels of Dietary Energy Intake

The objective of this study was to characterize follicular dynamics in pre-pubertal, pubertal and post-pubertal periods, as well as the effect of high-energy intake on follicular development and age at puberty in heifers. Thirty-one Nelore (Bos indicus) heifers, 6 months old, were randomly assigned to receive two different diets: one of low (GI) and other of high dietary energy intake (GII). Animals were evaluated in relation to body weight gain by being weighed every 21 days. Heifers were evaluated every other day by real-time linear ultrasonography to characterize ovarian structures development from weaning to post-pubertal period. Blood samples were collected to determine plasmatic concentrations of progesterone by RIA method. The ovulation was determined when progesterone concentrations were >1 ng/mL in three consecutive samples, and by ultrasound images of corpus luteum; and oestrous behaviour in some animals. Age at puberty differed among heifers of GII (17.00 +/- 0.46 months) compared with heifers of GI (19.87 +/- 0.47 months; p < or = 0.05). Maximum size of the dominant follicles at pre-pubertal period was greater in GII heifers than in GI (10.52 +/- 0.33 and 9.76 +/- 0.15 mm, respectively; p < or = 0.05). As heifers approached first ovulation time, size of dominant follicle increased (11.75 +/- 0.37 mm for GI and 12.52 +/- 0.91 mm for GII; p < or = 0.05). Body weight at puberty was not different in both groups (302.33 +/- 27.31 kg for GI and 326.19 +/- 27.78 kg for GII heifers; p > 0.05). We conclude that animals receiving high dietary energy intake attained the puberty earlier and the development of follicles were different than in low dietary energy intake.     

Retracted: Effect of Post‐Thaw Storage Time on Motility and Fertility of Cryopreserved Beluga Sturgeon (Huso huso) Sperm

The aim of this study was to test the influence of post ‐ thaw storage time on the duration of sperm motility, percentage of motile sperm, and fertilization and hatching rates of fresh sperm and sperm stored for 0, 30 and 60 min at 4°C post‐thawing. After being frozen in liquid nitrogen and then thawed, the percentage of motile sperm and duration of motility were not affected by 30 min of storage at 4°C, whereas a significant decline in these parameters was observed after 60 min of storage. Similarly, fertilization and hatching rates were significantly affected within 60 min of storage at 4°C, and the fertility of frozen‐thawed sperm was significantly lower than that of fresh sperm. We conclude that cryopreserved sperm of beluga sturgeon could be stored for 30 min without the loss of sperm quality. This described procedure for beluga sturgeon cryopreservation is reliable and efficient and therefore can be recommended for hatchery practice after scaling up this technique.     

Neotropical Bats from Costa Rica harbour Diverse Coronaviruses

Bats are hosts of diverse coronaviruses (CoVs) known to potentially cross the host–species barrier. For analysing coronavirus diversity in a bat species‐rich country, a total of 421 anal swabs/faecal samples from Costa Rican bats were screened for CoV RNA‐dependent RNA polymerase (RdRp) gene sequences by a pancoronavirus PCR. Six families, 24 genera and 41 species of bats were analysed. The detection rate for CoV was 1%. Individuals (n = 4) from four different species of frugivorous (Artibeus jamaicensis, Carollia perspicillata and Carollia castanea) and nectivorous (Glossophaga soricina) bats were positive for coronavirus‐derived nucleic acids. Analysis of 440 nt. RdRp sequences allocated all Costa Rican bat CoVs to the α‐CoV group. Several CoVs sequences clustered near previously described CoVs from the same species of bat, but were phylogenetically distant from the human CoV sequences identified to date, suggesting no recent spillover events. The Glossophaga soricina CoV sequence is sufficiently dissimilar (26% homology to the closest known bat CoVs) to represent a unique coronavirus not clustering near other CoVs found in the same bat species so far, implying an even higher CoV diversity than previously suspected.     

Body development, carcass, and meat quality of confined lambs fed increasing levels of whole rice meal

The objective of this trial was to evaluate the effect of whole rice meal (WRM) inclusion in the concentrate upon body development, carcass traits, and meat quality of lambs. Twenty-four castrated lambs with an average initial body weight of 17.90?±?2.72 kg were randomly blocked according to two genetic groups (Corriedale and Texel by Corriedale crossbreds). Three isocaloric (11.3 MJ/kg of metabolizable energy) and isonitrogenous (17 % crude protein) diets were offered to the animals for 74 days. Diets consisted of 40 % forage and 60 % concentrate diet, on a dry matter basis, with 0, 15, or 30 % of WRM inclusion into the concentrate. Body growth (after slaughter), carcass, and meat traits were evaluated on each animal. Results obtained indicated that genotype did not affect body growth, carcass, and meat traits except for yellowness. No significant interaction between diet and genotype were detected. Inclusion of up to 30 % WRM did not significantly (P?>?0.05) affect body growth, carcass, and meat traits, except for meat color. Meat luminosity progressively increased (36.32?+?0.055X) while redness (15.13???0.03X) decreased with the inclusion of WRM in the diet, but still remained within acceptable values. The study indicates that WRM may be included up to 30 % in the concentrate replacing corn without adverse effects upon body development, carcass traits, and meat quality of lambs.     

Gross Anatomy of the Brachial Plexus in the Giant Anteater (Myrmecophaga tridactyla)

Ten forelimbs of five Myrmecophaga tridactyla were examined to study the anatomy of the brachial plexus. The brachial plexuses of the M. tridactyla observed in the present study were formed by the ventral rami of the last four cervical spinal nerves, C5 through C8, and the first thoracic spinal nerve, T1. These primary roots joined to form two trunks: a cranial trunk comprising ventral rami from C5‐C7 and a caudal trunk receiving ventral rami from C8‐T1. The nerves originated from these trunks and their most constant arrangement were as follows: suprascapular (C5‐C7), subscapular (C5‐C7), cranial pectoral (C5‐C8), caudal pectoral (C8‐T1), axillary (C5‐C7), musculocutaneous (C5‐C7), radial (C5‐T1), median (C5‐T1), ulnar (C5‐T1), thoracodorsal (C5‐C8), lateral thoracic (C7‐T1) and long thoracic (C6‐C7). In general, the brachial plexus in the M. tridactyla is similar to the plexuses in mammals, but the number of rami contributing to the formation of each nerve in the M. tridactyla was found to be larger than those of most mammals. This feature may be related to the very distinctive anatomical specializations of the forelimb of the anteaters.