Evaluation of Elnady preserved tissues as a teaching aid for undergraduate animal science courses.

The use of tissue specimens for undergraduate instruction is a very valuable tool. However, fresh tissue specimens are not always available and many common preservation techniques can result in discoloration, offensive odors, and/or dangerous chemical residues. The Elnady Technique was developed as a means to produce tissue specimens that "are realistic, durable, have no offensive odor, and are dry, soft and flexible" (Elnady, F.A. 2016 The Elnady Technique: An innovative, new method for tissue preservation. Altex. 33:237-242. doi:10.14573/altex.1511091). Briefly for soft tissue, specimens were preserved by fixing in formalin. The tissue specimen was then dehydrated with a series of acetone baths. Once the tissue was fully dehydrated, the specimen was impregnated in glycerin. Excess glycerin was then removed by draining followed by immersion in cornstarch. Cornstarch residue was removed with a soft brush, and the specimen was stored in a plastic bag. Multiple specimens (including the female reproductive tract of the cat, goat, horse, and sow; digestive tract of cat, chicken, and dog; 1-day-old lamb stomach; goat rumen, reticulum, omasum, and abomasum; and sheep heart and kidney) have been preserved and used in various animal science course laboratories (126 laboratory sections and 1,696 students at Berry College). Some of the specimens have been in use for seven years and are still in usable condition. Anonymously surveyed Berry College Animal Science Faculty strongly agreed or agreed that Elnady preserved tissues are a useful teaching aid (n = 5). The Elnady Technique has proven to be a useful means of preserving tissue samples used in undergraduate animal science courses.

Effect of oral meloxicam administration on growth performance and behavior of pre-weaning age calves following band castration.

The objective of this study was to determine if oral meloxicam (M; a nonsteroidal anti-inflammatory drug) administered at castration to pre-weaning age calves affected average daily gain (ADG) or behavior. Prior to castration (d -14), Angus bulls were weighed and randomly assigned to be band castrated (BAN; n = 8; age = 90.2 ± 6.5 d; BW = 146.3 ± 11.4 kg; scrotal circumference = 16.0 ± 0.5 cm) or castrated with M (BAN + M; n = 9; age = 102.1 ± 6.2 d; BW = 146.0 ± 7.7 kg; scrotal circumference = 16.1 ± 0.3 cm). Six bulls selected to remain bulls based on pedigree and phenotype were maintained in the same pasture (BULL; age = 104.2 ± 6.1 d; BW = 172.1 ± 8.7 kg; scrotal circumference = 17.5 ± 0.4 cm). On d 0, BAN and BAN + M had a rubber band applied tightly around the scrotum, and BAN + M also received oral M (2 mg/kg BW). On d 1, 14, and 28, animals were weighed and a blood sample was collected to determine circulating concentrations of haptoglobin and fibrinogen. Data loggers were affixed to the legs of calves immediately prior to castration (d 0) to record behaviors [mean lying time (h/d), mean lying bouts (n/d), and steps (n/d)] at 1-min intervals and removed on d 28. Behavior and plasma data were tested for effect of treatment, day, and treatment × day interaction, and ADG data were tested for effect of treatment, period (d -14 to 1, d 1 to 14, and d 14 to 28), and treatment × period interaction using JMP procedures for repeated measures (SAS Inst. Inc., Cary, NC). BULL in period d 0 to 14 had greater ADG than all other treatment period combinations, and BULL had greater ADG than BAN or BAN + M overall (P < 0.05). There was no effect of M treatment on circulating concentrations of fibrinogen or haptoglobin (P > 0.05). On d 7 and 15, BAN took more steps than BAN + M (P < 0.05). BAN + M had more lying bouts than BAN on d 13 and 14 (P < 0.05). Overall, M administration had no effect on ADG post-castration and only had minor impacts on behavior in calves band castrated pre-weaning.

Trimming and Re-shoeing Results in More Steps per Day and More Time Spent Lying per Day.

To examine the impact of trimming and re-shoeing on behavior, light horse geldings (3-21 year-old Quarter Horse, Dutch Warmblood, or Thoroughbred) were fitted with three-axis accelerometers (IceTag, Ice Robotics, Edinburgh, Scotland) on the left rear limb. Boots were placed under the accelerometer, and both were removed daily for approximately 1 hour while horses were stalled for morning feeding to examine the horses' limb. After a two-day adaptation period and five days of activity tracking, horses were treated by having shoes removed, feet trimmed, and new shoes fitted (re-shod; n = 3) or being handled but not trimmed or fitted with new shoes (sham; n = 4). Horse activity was monitored for five days after treatment. Steps per day, time spent lying per day, and the number of lying bouts were tested for effects of treatment, time (before or after treatment), and interaction of treatment by time using procedures for repeated measures with JMP Software (version 7, SAS Inst. Inc, Cary, NC). Means separation was performed using the Student's t-test. There was a treatment by time interaction on time spent lying per day (P = .0447) and steps per day (P = .0501). Re-shod spent more time lying after treatment than before (121.4 ± 22.8 vs 66.8 ± 22.8 minutes per day, respectively). After treatment, re-shod also took more steps than sham (3499 ± 527 vs 3056 ± 456 steps per day, respectively). These results may indicate increased mental and physical comfort following trimming and re-shoeing in horses.

Intravenous infusion of kisspeptin increased serum luteinizing hormone acutely and decreased serum follicle stimulating hormone chronically in prepubertal bull calves.

Kisspeptin (KP) is a hypothalamic neuropeptide that stimulates the secretion of gonadotropin releasing hormone. To determine the acute and chronic effects of KP on serum concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH), prepubertal bull calves [12 ± 1 (SD) weeks of age; 96.5 ± 14.5 kg BW] were administered one of four treatments [0.0 (control; CON), 0.125 (L-KP), 0.25 (M-KP), or 0.5 (H-KP) µg of KP/kg BW/hour] by intravenous infusion for 76 h. Blood samples were collected every 15 min for the first (acute; 1-6 h; Day 1) and last (chronic; 71-76 h; Day 4) 6 h of the intravenous infusions. Serum concentrations of LH and FSH were determined by radioimmunoassay. For each day, effects of treatment, time, and interactions on LH and FSH concentrations and pulse parameters were analyzed using procedures for repeated measures with JMP Software (SAS Inst. Inc., Cary, NC). There was a treatment effect (P = 0.002) and a treatment × time interaction during Day 1 (P = 0.02) such that LH concentrations were greatest following administration of all doses of KP when compared to CON. However, there was no treatment effect (P = 0.57) or a treatment × time interaction during Day 4 (P = 0.20) on serum LH concentrations. There was a treatment by day interaction (P = 0.02) on mean serum FSH concentrations. Most notably, on Day 4 mean serum FSH concentrations during intravenous infusion of M-KP and H-KP doses were less than that of CON. There was a treatment by day interaction (P = 0.0054) on FSH pulse amplitude concentrations, such that intravenous infusion of all doses of KP on Day 4 decreased FSH pulse amplitudes. In conclusion, acute infusion of KP increased LH concentrations and chronic infusion of KP decreased FSH concentrations. Despite the potential suppression of the hypothalamic-pituitary-gonadal axis with chronic infusion of KP, there are likely applications of KP, KP analogs, or KP receptor agonists to hasten the onset of puberty in livestock.

Kisspeptin Stimulates Growth Hormone Release by Utilizing Neuropeptide Y Pathways and Is Dependent on the Presence of Ghrelin in the Ewe.

Although kisspeptin is the primary stimulator of gonadotropin-releasing hormone secretion and therefore the hypothalamic-pituitary-gonadal axis, recent findings suggest kisspeptin can also regulate additional neuroendocrine processes including release of growth hormone (GH). Here we show that central delivery of kisspeptin causes a robust rise in plasma GH in fasted but not fed sheep. Kisspeptin-induced GH secretion was similar in animals fasted for 24 hours and those fasted for 72 hours, suggesting that the factors involved in kisspeptin-induced GH secretion are responsive to loss of food availability and not the result of severe negative energy balance. Pretreatment with the neuropeptide Y (NPY) Y1 receptor antagonist, BIBO 3304, blocked the effects of kisspeptin-induced GH release, implicating NPY as an intermediary. Kisspeptin treatment induced c-Fos in NPY and GH-releasing hormone (GHRH) cells of the arcuate nucleus. The same kisspeptin treatment resulted in a reduction in c-Fos in somatostatin (SS) cells in the periventricular nucleus. Finally, blockade of systemic ghrelin release or antagonism of the ghrelin receptor eliminated or reduced the ability of kisspeptin to induce GH release, suggesting the presence of ghrelin is required for kisspeptin-induced GH release in fasted animals. Our findings support the hypothesis that during short-term fasting, systemic ghrelin concentrations and NPY expression in the arcuate nucleus rise. This permits kisspeptin activation of NPY cells. In turn, NPY stimulates GHRH cells and inhibits SS cells, resulting in GH release. We propose a mechanism by which kisspeptin conveys reproductive and hormone status onto the somatotropic axis, resulting in alterations in GH release.