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The objective was to evaluate the influence of cell-mediated immune response classification on performance of dairy cattle experiencing conditions of heat stress on pasture. On d 0, pregnant, lactating dairy cows (n = 27; 18 Holstein and 9 Jersey) received a subcutaneous sensitization dose of killed Candida albicans (CA; 0.5 mg) with Quil-A adjuvant (0.75 mg) in 2.5 mL of PBS. Tail skin fold thickness (SFT) was measured with a Harpenden caliper on d 14 immediately following an intradermal injection of killed CA (0.1 mg in 0.5 mL of PBS) in the right tail skin fold and a control injection (PBS) in the left tail skin fold. On d 15, change in SFT was measured and used to assign cell-mediated immune response classifications (CMIR) as High (HR; >0.5 SD above the mean; n = 9), Intermediate (IR; within 0.5 SD above or below the mean; n = 10), or Low (LR; >0.5 SD below the mean; n = 8). Cows from each CMIR were assigned to 1 of 3 environmental conditions (EC): No Abatement (no heat abatement provided; n = 9), Shade (portable shade structure; n = 9), or Sprinklers (polyvinyl chloride sprinkler system; n = 9) for a 38-d period (July 1, 2019 to August 8, 2019). Daily Milk Yield (DMY), Reticulorumen Temperature (RT), Heat Stress Score (HSS; 0 = respiration rate of < 80 breaths/min to 4 = moribund, labored breathing), and instances of Mouth Open (MO), Tongue Out (TO), and Drool were recorded daily. Respiration rate (RR; breaths/min) was recorded 3 times/day (morning, midday, and late afternoon) and averaged on Monday, Wednesday, and Friday weekly. Body Condition Score (BCS; 1 = emaciated to 5 = obese) was recorded weekly. Data were analyzed using MIXED procedures of SAS specific for repeated measures with CMIR, EC, Breed, Time and 2-way interactions as fixed effects and Pen as random. Low exhibited the lowest HSS and BCS, but the greatest MO and TO instances (P < 0.02). High exhibited the greatest instances of Drool (P < 0.02). Heat stress score, MO, and Drool were greatest in the No Abatement group (P < 0.01). Respiration rate was greatest in the No Abatement and Shade groups relative to Sprinklers (P < 0.01). Daily milk yield, RT, and Drool were increased whereas HSS and RR were decreased in Holstein relative to Jersey cows (P < 0.01). Interactions (P < 0.05) included: CMIR by EC for DMY, HSS, RR, MO, TO, and Drool; CMIR by Breed for RT, DMY, and BCS; EC by Breed for RT, DMY, HSS, and RR; and EC by Time for DMY, HSS, BCS, RR, MO, and TO. There was an effect of Time for all variables (P < 0.05). Preliminary results suggest an influence of cell-mediated immune response classification on performance of dairy cattle experiencing conditions of heat stress and warrant future studies with an increased number of animals.

The study was conducted to evaluate the effects of feeding frequencies (one, two, three, and four times per day) on the performance of male feedlot lambs. Forty Santa Inês male lambs were used with an average age of 120 days approximately and initial body weight of 24.90 ± 1.8 kg (mean ± S.D.). The lambs were distributed to treatment groups in a completely randomized experimental design, with 10 animals per treatment, placed in individual pens. A standard diet consisted of Tifton-85 hay and concentrate with a ratio of 60:40, respectively. The different feeding frequencies did not influence (p &gt, 0.05) the intake of nutritional components, blood parameters, weight gain, ingestive behavior, carcass characteristics, or meat quality of male feedlot lambs. The feeding frequency of 3 and 4 times per day promoted the highest digestibility of neutral detergent fiber (NDF, p = 0.008) and total digestible nutrients (TDN, p = 0.002). The feeding frequency of 3 times per day promoted the highest digestibility of crude protein (CP, p = 0.005). The time devoted to rumination (min/kg DM) was increased (p = 0.029) when the diet was supplied once a day compared to the other feeding frequencies. Based on these results, the recommended feeding frequency for male feedlot lambs is once a day. When feeding at this frequency, the ingestive behavior, productivity, carcass characteristics, and meat quality of male feedlot lambs will not be compromised.