Eighty-four Angus crossbred heifers (13 ± 1 mo of age, 329.5 ± 61.92 kg of body weight [BW]) were used in a generalized randomized block design with a 2 × 2 factorial arrangement of treatments. The factors evaluated were: 1) diet type (whole plant sorghum silage [SS] vs. byproducts-based [BP]), and 2) feed additive: Aspergillus oryzae prebiotic (AOP; 2 g/d) vs. Negative control (CTL; 0 g/d), resulting in four treatments: sorghum silage-control (SC), sorghum silage-AOP (SA), byproducts-control (BC), and byproducts-AOP (BA). Heifers were stratified by body weight (BW), randomly assigned to treatments (21 heifers per treatment) and housed in 12 pens equipped with two GrowSafe feed bunks each to measure individual dry matter intake (DMI). After a 14-d adaptation, BW was measured every 14 d for 56 d. Chewing activity was monitored through collar-mounted HR-Tags (heat-related tags). Following the performance period, apparent total tract digestibility was measured in 40 heifers, using indigestible neutral detergent fiber as a marker. Heifers fed with the BP diets had greater DMI (2.92% vs. 2.59% of BW, P < 0.01) and average daily gain (ADG; 1.16 vs. 0.68 kg, P ≤ 0.01) than heifers fed with SS diets. Compared with BP-fed animals, heifers consuming the SS diets had 23 more visits/d to the feed bunks (P ≤ 0.01), consumed 53% less dry matter on each visit (P ≤ 0.01), and spent 39% more min chewing/d and 63% more min chewing/kg of DMI (P ≤ 0.01). However, chewing measured in min/kg of neutral detergent fiber intake was not affected by treatment (average 111.3 min/kg of NDF intake). Feeding AOP improved gain:feed (GF) by 15% in BP-fed heifers (0.120 vs. 0.104 kg/kg; P < 0.05). Inclusion of AOP increased organic matter digestibility (OMD) in SS diets (55.88% vs. 49.83%; P < 0.01), whereas it decreased OMD in BP diets (61.67% vs. 65.77%; P < 0.05). In conclusion, ADG and GF of BP-fed heifers was greater than SS-fed heifers, and GF was greater with AOP supplementation in BP-fed heifers. Improvement in GF in BP-fed heifers was likely not related to differences in nutrient digestibility as AOP inclusion did not enhance digestibility in the BP diet. Additionally, the effects of the AOP inclusion appear to be diet-dependent, where the 15% improvement in GF by AOP occurred in heifers fed with the more fermentable diet. Therefore, further research should explore the mechanisms responsible for the observed improvements in growth performance when feeding AOP to BP-fed heifers. This experiment evaluated the effects of the dietary inclusion or not of Aspergillus oryzae prebiotic (AOP; 2 g/d) in two contrasting diets: sorghum silage-based (SS) vs. byproducts-based (BP), on growth performance, nutrient digestibility, and feeding behavior of growing heifers. A total of 84 Angus crossbred heifers were used in the study. Heifers fed with the BP diets had greater feed intake, average daily gain, and final body weight. In addition, heifers fed with the BP diets had reduced number of visits to the feed bunk but consumed more in each visit than heifers fed with the SS diets. Additionally, heifers fed with the BP diets had lesser chewing activity measured in total min/d and in min/kg of dry matter intake; however, chewing activity measured in min/kg of neutral detergent fiber was not influenced by treatments. The inclusion of AOP increased the gain:feed ratio by 15% in heifers fed with the BP diet but did not influence this variable in the SS diet. The inclusion of AOP increased nutrient digestibility in heifers fed with the SS diet and decreased nutrient digestibility in heifers fed with the BP diet. These results show that feeding AOP can enhance growth performance in beef heifers in a diet-dependent manner.

Grazing livestock in subtropical and tropical regions are susceptible to prolonged exposition to periods of extreme environmental conditions (i.e., temperature and humidity) that can trigger heat stress (HS). Currently, there is limited information on the effects of HS in the cow-calf sector globally, including in the southern U.S., as well as on mitigation strategies that could be implemented to improve animal well-being and performance. This study evaluated the impact of artificial shade (SHADE vs. NO SHADE) and breed (ANGUS vs. BRANGUS) on performance of pregnant-lactating cows, nursing heifers, and their subsequent offspring. Twenty-four Angus and 24 Brangus black-hided cows [579 ± 8 kg body weight (BW); approximately 85 d of gestation] and their nursing heifers (approximately 174 d of age) were randomly allocated to 12 ‘Pensacola’ bahiagrass pastures (Paspalum notatum Flüggé; 1.3 ha, n = 4 pairs/pasture), with or without access to artificial shade [NO SHADE BRANGUS (NSB), NO SHADE ANGUS (NSA), SHADE BRANGUS (SB), and SHADE ANGUS (SA)] for 56 d that anticipated weaning during the summer season in Florida. Body condition score (BCS) of cows, blood samples, and BW of cow-calf pairs were obtained every 14 d during the 56-d experimental period until weaning. Following weaning (d 56), treatments were ceased, and cows and weaned heifers were managed alike. Weaned heifers were randomly allocated to 4 pens (n = 12/pen) equipped with GrowSafe feed bunks for 14 d to assess stress responses during weaning via plasma haptoglobin. An effect of SHADE × BREED interaction was detected for cow ADG, BW change, final BW, and final BCS, where SB had the greatest ADG, BW change, final BW, and final BCS. On d 14, SA cows had the greatest concentrations of insulin whereas on d 28 NSB had the lowest concentrations, NSA the greatest, and SA and SB being intermediate. On d 56, SA tended to have the greatest plasma insulin concentrations and SB the lowest. Weight gain per area (kg/ha) tended to be 11.4 kg/ha greater in SHADE vs. NO SHADE pastures. Pre-weaning calf ADG tended to be 0.14 kg greater for SHADE vs. NO SHADE calves. Weaning weight and BW at 14-d post-weaning were lesser for NSB vs. NSA, SA, and SB, whereas no differences in postweaning ADG or haptoglobin were observed. Effects of SHADE × BREED × day interaction was detected on plasma concentrations of IGF-1, in which NSA heifers had the lowest concentrations on weaning day. Gestation length was greater for SHADE vs. NO SHADE cows, but with no impacts on subsequent calf birth and weaning weight. In summary, providing artificial shade to pregnant-lactating beef cows increased body weight gain of nursing heifers and Brangus cows, while no impact on Angus dams were observed. The provision of artificial shade during the first trimester of gestation did not alter growth performance of the subsequent offspring at birth and weaning even though gestation length was longer.

An experiment was designed to evaluate the effects of CaO on ruminal in situ degradability (RISD) of forage components and in vitro organic matter digestibility (IVOMD) of warm-season forages. Bahiagrass (Paspalum notatum; BH) or Tifton 85 bermudagrass (Cynodon spp.; BM) hay were stored in 20-L buckets in two consecutive years (n = 4/treatment) as follows: 1) untreated dry BH or BM (DH); 2) hydrated BH or BM stored for 7 d (W7); 3) hydrated BH or BM stored for 14 d (W14); 4) hydrated BH or BM + 5% [dry matter (DM) basis] CaO stored for 7 d (CO5-7); 5) hydrated BH or BM + 5% (DM basis) CaO stored for 14 d (CO5-14); and 6) hydrated BH or BM + 10% (DM basis) CaO stored for 14 d (CO10). With exception of the dry treatment (DH), tap water was added to forages under the remaining treatments to reach a DM concentration of 50%. Ruminal in situ degradability of DM, organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) of BH and BM was determined for 24, 48, and 72 h in two ruminally cannulated steers consuming BH. Data were analyzed as a randomized block design using bucket as the experimental unit. The model included the fixed effect of treatment and the random effect of year. Concentration of NDF was reduced (P < 0.001) when BH and BM were treated with 10% and 5% CaO and compared with DH. However, only CO10 promoted a reduction (P = 0.007) in ADF concentration of BH, whereas CO10 and CO5, regardless of storage length, reduced (P ≤ 0.006) ADF concentration of BM, when compared with DH. At all ruminal incubation time points, a treatment effect (P < 0.001) was observed on RISD of DM, OM, CP, NDF, and ADF of BH and BM, where all treatments containing CaO promoted greater degradability when compared with DH, W7, and W14, which did not differ (P > 0.05). Ruminal degradability of forage components was greatest (P < 0.05) for CO10, followed by CO5-7 and CO5-14, which did not differ (P > 0.05). In vitro organic matter digestibility was increased (P < 0.001) in both BH and BM when CaO was applied and compared to DH. Treatment of BH and BM with CaO seems to be an effective method of promoting increased digestibility of forage components, including fiber fractions, when applied at 5% of the forage DM with potential additional benefits to BH when applied at 10%.

Garlic (Allium sativum) contains secondary compounds that are known to modify rumen fermentation parameters and decrease methane (CH₄) emissions. The objective was to evaluate the effects of increasing the inclusion levels and processing methods of garlic on in vitro fermentation and CH₄ production. Treatments were arranged in a randomized complete block design with a 2 × 3 × 2 + 1 factorial arrangement, where the main factors were the initial condition of garlic (intact or smashed), drying process (freeze-dried, oven-dried, or autoclaved), and garlic proportion in the diet (2.5 and 5%) and one control (without garlic supplementation). Incubations were conducted using corn silage and cotton-gin trash (80:20, respectively) as basal substrates on three different days. Final pH, the concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH₃-N), in vitro organic matter digestibility (IVOMD), total gas production, and CH₄ concentration were determined after 24 h. Initial garlic condition or drying processing neither modify (p > 0.05) the in vitro fermentation nor the CH₄ production. However, increasing garlic inclusion linearly increased (p < 0.05) IVOMD, the concentration of the total VFA, and the proportion of propionate. Also, the concentration of NH₃-N and the proportion of acetate increased quadratically (p < 0.05) with greater garlic inclusions. Finally, garlic inclusion did not affect (p > 0.05) gas and CH₄ production. In conclusion, increasing garlic levels, but not the processing methods, improved in vitro fermentation but did not modify CH₄ emissions under in vitro conditions.

Yeast-fermentation products are promising feed additives to enhance ruminal fermentation, improve feed efficiency and animal performance, and potentially mitigate enteric methane (CH4) emissions. This study aimed to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation-derived postbiotic on ruminal fermentation parameters, CH4 production, and nutrient utilization in beef steers consuming a high-grain diet. Six ruminally cannulated Angus crossbred steers (783 ± 29 kg of bodyweight) were used in a crossover design (42-d period), where they received a basal diet comprised of (dry matter [DM] basis) 65.9% cracked corn, 14.4% bermudagrass hay, 9.9% dry distillers grains plus solubles, 4.9% cottonseed hulls, and 4.9% of vitamin–mineral supplement. Each day, steers were individually fed a carrier of dry distillers’ grains plus solubles (250 g/d as fed) with one of the following treatments: CTL, carrier only; or SCFP, carrier plus 28 g/steer/d of a Saccharomyces cerevisiae fermentation-derived postbiotic (NaturSafe, Diamond V, Cedar Rapids, IA). Ruminal fermentation parameters, including pH, concentration of ammonia nitrogen (NH3-N), volatile fatty acids (VFA), total gas, CH4 production, and in vitro organic matter (OM) digestibility, were assessed using an ex vivo model. Additionally, in vivo measurements of pH, VFA, and NH3-N were conducted over 24 h, and apparent total tract digestibility was determined using collected feed and fecal samples. Data was analyzed as a crossover design including treatment, order, and period as fixed effects, and steer within order as a random effect. Supplementation with SCFP had no effect (P > 0.10) on the ruminal fermentation parameters assessed using the ex vivo model. Daily supplementation of SCFP in vivo showed no effect (P = 0.12) on ruminal pH or concentration of NH3-N; however, a decrease (P = 0.04) in concentration (mM) of total VFA was observed due to reduced concentration of propionate (P = 0.03) and butyrate (P < 0.01). The acetate to propionate ratio was greater (P = 0.02) in SCFP compared with CTL. Supplementation of SCFP resulted in a decrease (P < 0.01) in molar proportion (MP; mol/100 mol) of butyrate and tended to reduce (P = 0.09) MP of propionate, yet MP of acetate and valerate increased (P = 0.02). Apparent total tract digestibility of DM, OM, and starch increased (P < 0.05), with crude protein digestibility showing a tendency to increase (P = 0.08) with SCFP inclusion. Thus, supplementing SCFP at a rate of 28 g/animal/d altered ruminal fermentation in vivo and improved the digestibility in this study.

Eighty-four Angus crossbred heifers (13 ± 1 mo, 329.5 ± 61.92 kg of BW) were used in a generalized randomized block design with a 2 × 2 factorial arrangement of treatments. The objective was to evaluate the effect of a feed additive inclusion under two growing diets. Factors included: 1) diet type (whole plant sorghum silage- or byproducts-based diet) and 2) feed additive inclusion [Amaferm (Aspergillus oryzae (extract)] included at 0 or 0.02% of the diet DM. This resulted in four treatments: sorghum-control (SC), sorghum-amaferm (SA), byproducts-control (BC) and byproducts-amaferm (BA). Heifers were housed in 12 pens (108 m²/pen; 7 heifers/ pen) equipped with GrowSafe technology, to measure individual dry matter intake (DMI). After a 14-d adaptation, BW was measured every 14 d, during 56 days, and chewing activity was monitored through collar-mounted HR-Tags (SCR Engineers Ltd., Netanya, Israel). Apparent total tract digestibility was measured on 10 heifers per treatment after the 56-d performance period, using indigestible NDF as a marker. Heifers fed the byproducts diet had (P ≤ 0.01) greater DMI as % of BW (2.92 vs. 2.59%) and greater average daily gain (1.16 vs. 0.68 kg/d). Amaferm improved gain-to-feed ratio by 15% in the byproducts diet (P ≤ 0.05) but it had no effect in the sorghum silage diet (P = 0.59). Conversely, Amaferm inclusion increased apparent total tract organic matter digestibility in the sorghum silage diet (SC = 49.8 vs. SA = 55.9%; P ≤ 0.01), whereas reduced it in the byproducts diet (BC = 65.8 vs. BA = 61.7%; P ≤ 0.05). Heifers fed a sorghum silage-based diet had (P ≤ 0.01) 39 and 63% greater chewing in min/d and min/kg of DMI, respectively; however, chewing in min/kg of NDF intake was similar across diets (average 111.3 min/kg of NDF intake).