PSX-A-10 Late-Breaking: Effects of paternal high energy diets on blastocyst development during in vitro embryo production in the bovine

The objective of this study was to evaluate the effect of paternal high energy diets on blastocyst development during in vitro embryo production (IVP). Eight sires were stratified by body weight (initial BW = 946 ± 85 kg) and randomly assigned to the same diet (NEm = 2.10, NEg = 1.44, CP = 14.1%, NDF = 16.6%, DM basis) fed at two different inclusion rates while having ad libitum access to bermudagrass hay (NEm = 1.02, NEg = 0.45, CP = 10.2%, NDF = 71.6). After a 10-d adaptation period, sires were individually fed to receive 0.5% (MAINT) or 1.25% [High gain (HG)] of their BW daily for 67 days. At the end of the feeding period, semen was collected through electroejaculation and frozen. Antral follicles were aspirated from ovaries obtained from a slaughterhouse and utilized for IVP in 4 independent replicates (n = 2,227 total oocytes). Cleavage rates were evaluated 48 h after fertilization and blastocyst development rates were evaluated after 7 days of embryo culture. The proposed treatments successfully induced differences in BW gain (P < 0.01; 2.28 vs -0.04 kg/d) and carcass composition (Rump fat: 1.63 vs. 0.41 cm, P = 0.08; Rib fat: 1.06 vs. 0.41 cm, P = 0.02; intramuscular fat: 3.5 vs. 3.0%, P = 0.36; for HG vs. MAINT sires, respectively). There was a significant decrease in cleavage rates (69.9 ± 2.5 vs. 65.0 ± 2.7; P < 0.04), blastocyst rate as a percentage of oocytes (16.7 ± 2.9 vs. 11.5 ± 2.1; P < 0.01), and blastocyst rates as a percentage of cleaved structures (24.1 ± 3.8 vs. 11.5 ± 2.1; P < 0.01) for HG compared with MAINT sires. In conclusion, sires fed diets that induce highly anabolic conditions had impaired blastocyst development compared to sires fed a maintenance diet.

Habituation Protocols Improve Behavioral and Physiological Responses of Beef Cattle Exposed to Students in an Animal Handling Class

Simple Summary

Students in agricultural programs have the opportunity to interact with animals during different teaching activities. However, students’ interactions with livestock may be distressing to the animals and can affect the students’ and animals’ safety. We investigate whether two human-animal habituation strategies, one with positive tactile stimulation and one without, would improve behavioral and physiological responses of beef heifers during a livestock handling class. Overall, heifers that received a habituation treatment had more positive behavior responses, and decreased physiological stress responses in comparison to heifers that were not exposed to habituation. Furthermore, the heifers exposed to the habituation with a positive tactile stimulation had the greatest improvements in behavior in comparison to control and non-stimulated heifers, exhibiting more positive behaviors when interacting with humans. Strategies to habituate cattle to human interaction with positive stimulation aligned with training humans that handle and interact with cattle on best practices and cattle behavior can improve behavior, reduce stress-related physiological responses and enhance safety for both humans and animals.

Abstract

Our objective was to determine the impact of different habituation protocols on beef cattle behavior, physiology, and temperament in response to human handling. Beef heifers were exposed to three habituation strategies: (1) tactile stimulation (brushing) in the working chute for seven consecutive days (STI; n = 18); (2) passage through the working chute for seven consecutive days (CHU; n = 19) and; (3) no habituation (CON; n = 19). Individual heifer respiratory rate (RR; n/min), internal vaginal temperature (VAGT; °C), and blood cortisol were measured. Further, behavior parameters were observed to generate a behavior score, and heifer interaction with students and their behavioral responses were recorded. Habituation with STI and CHU resulted in improved numerical behavioral scores compared to CON, and greater (p ≤ 0.05) handling latencies. Vaginal temperature was decreased in STI compared to CHU and CONT (p ≤ 0.05). Cortisol concentration did not differ among treatments, but decreased (p ≤ 0.05) from the start of the experiment to 14 days after treatment initiation. Both habituation protocols showed benefits, but heifers that received the positive tactile stimulation in the chute had the greatest behavior improvements. Furthermore, these heifers responded more calmly during student-animal interactions in class, which is beneficial for the students’ and animals’ safety.