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Simple Summary: Enhancing the energy density of lamb diets is a proven method to improve their productivity. While using carbohydrates for this purpose may seem intuitive, it can lead to undesirable shifts in ruminal metabolism, potentially triggering metabolic diseases. Hence, substituting carbohydrates with lipids is favored. Nevertheless, lipids, though effective, can also disrupt ruminal fermentation parameters. Among these lipids, soybean oil stands out for its positive impact on both beef and dairy cattle, leading to improved performance. In our study, we sought to assess the effects of soybean oil supplementation on performance, digestibility, feeding behaviour, and blood metabolites of feedlot lambs. Our findings indicate that the inclusion of soybean oil resulted in a linear reduction in nutrient intake, consequently lowering the average daily gain of the lambs. Additionally, soybean oil supplementation induced selective feeding behaviour among the lambs. Based on our observations, we recommend incorporating soybean oil into lamb diets at a maximum inclusion rate of 41 g/kg DM to optimize production parameters. The strategy implemented to adapt lambs to increasing levels of high-fat diet mitigated the detrimental effects of lipids on the rumen, with high-density energy intake being the constraining factor on performance. The objective of the current study was to evaluate the effects of soybean oil inclusion in diets on feeding behaviour, digestibility, performance, and blood metabolites of feedlot lambs. Forty non-castrated Santa Inês lambs with a mean age of 5 months and initial body weight of 34.88 ± 3.19 kg were used in a 40-day feeding trial. The lambs were distributed in five experimental diets with the inclusion of increasing soybean oil (SO) levels: 0, 30, 60, 90, and 120 g/kg DM. The SO inclusion promoted a linear reduction in DM intake (p < 0.001), crude protein (CP, p < 0.001), non-fibrous carbohydrates (NFC, p < 0.001), and total digestible nutrients (TDN, p = 0.004). There was an increasing quadratic effect on the intake of ether extract (EE; p = 0.002) and decreasing for neutral detergent fiber (p = 0.005). The soybean oil inclusion promoted the greater apparent digestibility of CP (p = 0.016), EE (p = 0.005), NDFom (p < 0.001), and TDN (p < 0.001); on the other hand, the apparent digestibility of NFC (p = 0.005) was decreased. The average daily gain decreased (p < 0.001) with SO inclusion. The SO inclusion increased feeding time (p = 0.004), reduced the efficiency of DM rumination (p = 0.001), and reduced the concentration of blood N-ureic (p < 0.001). Considering the productive parameters, SO can be included in diets and it is recommended that we include SO of up to 41 g/kg DM in diets for fattening lambs as the ideal maximum level. The strategy implemented to adapt lambs to increasing levels of high-fat diet mitigated the detrimental effects of lipids on the rumen, with high-density energy intake being the constraining factor on performance. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study proposed to evaluate the effects of replacing ground corn by crude glycerin and soybean meal by cottonseed cake, in association or not, on nutrient intake, apparent digestibility, feeding behavior, ruminal fermentation, nitrogen utilization, and blood metabolites of feedlot lambs. Eight ruminally-cannulated lambs (average age: 1 year; initial body weight: 51.10 ± 8.94 kg) were randomly distributed in a 4 × 4 double Latin square design, in a 2 × 2 factorial scheme, with 21-day periods (last six days for data collection). Four experimental diets were tested with different sources or combinations of energy and protein ingredients in the concentrate, respectively: 1) ground corn and soybean meal; 2) ground corn and cottonseed cake; 3) crude glycerin and soybean meal; 4) crude glycerin and cottonseed cake. An interaction effect between energy and protein sources occurred on nutrient intake and digestibility of ether extract (EE; P < 0.05). The lowest values of nutrient intake other than EE were observed in lambs fed with crude glycerin (P < 0.05). Higher intake of neutral detergent fiber (NDF) was observed in lambs fed with cottonseed cake (P < 0.05). Higher apparent digestibilities of crude protein (CP) and EE, and lower non-fibrous carbohydrates (NFC) and total digestible nutrients (TDN) were observed in lambs fed with crude glycerin (P < 0.05). No differences were observed in the time spent in feeding, rumination, idling activities, chewing, number and time per period spent doing the activities, as well as the feeding and rumination efficiencies of DM and NDF (P > 0.05). Diet and time effects were observed on ruminal fermentation parameters (P < 0.05). An interaction effect occurred between the energy source and time was observed for pH, acetate, and butyrate concentrations, and acetate:propionate ratio (P < 0.05). Lambs fed with crude glycerin showed lower intake and fecal excretion of nitrogen than those fed ground corn (P < 0.05). The triglyceride concentration was affected by the energy source (P < 0.05); with higher concentrations being observed when crude glycerin replaced ground corn. Furthermore, there was an interaction effect between energy and protein sources in the concentrations of total proteins (P < 0.01) and globulin (P < 0.01); with lower values in diets with ground corn and cottonseed cake. Cottonseed cake can replace 100% of soybean meal in diets without affecting the ingestive behavior and metabolism of feedlot lambs. On the other hand, replacing 100% ground corn with crude glycerin has potential for use in lamb feedlot diets; however more studies need to be performed. Furthermore, we recommend the use of these alternative sources, since the combination of crude glycerin and cottonseed cake can replace 100% of ground corn and soybean meal in sheep diets. • Crude glycerin and cottonseed cake are potential by-products for feeding lambs. • Crude glycerin affects nutrient intake without affecting DM digestibility. • Crude glycerin and cottonseed cake do not affect the feeding behavior of lambs. • Crude glycerin and cottonseed cake diets do not affect nitrogen balance in lambs. • Acetate content is higher with cottonseed cake and lower with crude glycerin diets. [ABSTRACT FROM AUTHOR]