Two experiments were performed to evaluate the effects of 1) increasing supplementation doses of a 50:50 (as-fed) liquid supplement of molasses and crude glycerol (M:G) on ruminal fermentation parameters and blood urea nitrogen (BUN) in beef steers consuming Tifton 85 bermudagrass (Cynodon spp.) hay and 2) different proportions of molasses and crude glycerol in a liquid supplement on in vitro fermentation and gas production kinetics. For Exp. 1, 8 ruminally cannulated, Angus-crossbred steers were used in a duplicated 4 × 4 Latin square design, had ad libitum access to Tifton 85 bermudagrass hay, and were randomly assigned to 1 of 4 treatments: 1) CTRL, no supplementation; 2) SUP1, 0.45 kg/d (as fed) of 50:50 M:G; 3) SUP3, 1.36 kg/d (as fed) of 50:50 M:G; and 4) SUP5, 2.27 kg/d (as fed) of a 50:50 M:G. For Exp. 2 in vitro batch cultures were conducted to test the same treatments from Exp. 1 and effects of different proportions of a M:G mixture (100:0, 75:25, 50:50, 25:75, and 0:100) when added to a hay substrate simulating the proportions of hay and liquid supplement used in SUP5. In Exp. 1, increasing doses of liquid supplement linearly decreased (P < 0.001) concentrations of NH₃-N, BUN, and acetate molar proportions, whereas propionate (P = 0.002) and butyrate (P < 0.001) molar proportions increased linearly. Treatment × time interactions were observed for ruminal pH (P < 0.001), where the greatest decrease was observed at 3 h postfeeding for animals consuming SUP5 (from 6.82 at 0 h to 6.32 at 3 h). In Exp. 2, decreases in acetate molar proportions (P < 0.001) and increases (P < 0.001) in propionate and butyrate molar proportions were also observed for either increasing doses of a 50:50 mixture or increasing proportions of glycerol in the mixture. Total VFA and in vitro organic matter digestibility were increased linearly (P < 0.001) as doses of a 50:50 mixture increased. Increasing doses of 50:50 M:G to growing beef heifers consuming bermudagrass hay caused a shift in VFA profile toward increases in propionate and decreases in acetate molar proportions. This was also confirmed in vitro, as the proportions of crude glycerol increased in a molasses:crude glycerol mix. Thus, molasses and crude glycerol combined seem to be useful to enhance performance in growing cattle consuming forage-based diets. Copyright © 2016. American Society of Animal Science .

Brassica carinata is a new oilseed crop with the potential of producing high-quality jet biofuel. A high-protein meal (~40% crude protein) is obtained as a byproduct of hexane-solvent oil extraction; however, limited research is available on the use of this meal as a protein supplement for beef cattle. A duplicated 4 × 4 Latin square design was used to determine the effects of supplementation with B. carinata meal on ruminal fermentation, digestibility, and blood metabolites in beef cattle consuming bahiagrass hay (Paspalum notatum Flüggé), compared with frequently used protein supplements. Eight Angus crossbred steers (473 ± 119 kg initial BW) were randomly allocated to 8 pens, over 4 periods of 28-d each. Within period, steers were assigned to one of four treatments: 1) 1.62 kg/d cottonseed meal (CSM); 2) 2.15 kg/d dry distillers grains plus solubles (DDGS); 3) 1.39 kg/d B. carinata meal pellets (BCM); or 4) 1.17 kg/d soybean meal (SBM), supplemented daily, on an isonitrogenous basis. Steers had ad libitum access to bahiagrass hay and water. Intake was measured using the GrowSafe system. Following a 14-d adaptation, feed and fecal samples were collected to determine apparent total tract nutrient digestibility using indigestible NDF as an internal marker. Blood and ruminal fluid samples were collected before providing the protein supplements and then every 3 h, during a 24 h period, to analyze urea nitrogen (PUN) and glucose in plasma, as well as ruminal pH, ammonia nitrogen (NH₃-N), and VFA concentrations. Data were analyzed using PROC MIXED of SAS with repeated measures. Model included the fixed effects of treatment, time, treatment × time, square, and period, and the random effects of steer(square) and steer(treatment). No effect of treatment (P > 0.05) was observed for pH, NH₃-N, or glucose concentration. An effect of treatment (P < 0.01) was observed for PUN, with steers receiving SBM having greater concentrations. A treatment × time interaction was observed (P < 0.05) for total VFA concentration, acetate to propionate ratio, and molar proportions of acetate, propionate, butyrate, and valerate. Steers consuming SBM had greater molar proportions of branched chain VFA (P < 0.01) compared with CSM and DDGS. There was no effect of treatment (P > 0.05) on intake or apparent total tract digestibility of nutrients. Brassica carinata performed similarly to commonly used protein supplements indicating its viability as a protein supplement for beef cattle.

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.

As a novel oilseed crop in Florida, Brassica carinata has the capacity of producing high-quality jet biofuel, with a protein-dense meal (~40% crude protein; CP) obtained as a by-product of oil extraction. Characterization of the meal protein is limited, yet necessary for formulation of beef cattle diets; therefore, the objective of this experiment was to determine ruminal and postruminal digestibility of protein from B. carinata. Eight ruminally cannulated Angus crossbred steers (473 ± 119 kg) were used in a duplicated 4 × 4 Latin square design, in which in situ ruminal and postruminal degradability of nutrients were evaluated. The three-step in vitro procedure was used to compare CP and amino acid (AA) degradation in B. carinata meal pellets (BCM) with that of cottonseed meal (CSM), dry distillers grains with solubles (DDGS), and soybean meal (SBM). In situ bags were incubated in the rumen for 0 to 96 hr, with the undegraded supplement remaining after 16 hr subjected to serial in vitro enzymatic solutions. Data were analyzed using the MIXED procedure of SAS. Ruminal rate of degradation of dry matter, organic matter, and CP was greatest (P ˂ 0.01; 10.9, 11.3, and 11.5 %/h, respectively) for SBM. Rumen degradable protein (RDP) content did not differ (P = 0.20; 47.8% and 55.1%, respectively) between CSM and DDGS, but was decreased (P ˂ 0.01) compared with SBM and BCM, which did not differ (P = 0.99; 72.3% and 71.8% RDP, respectively). Compared with DDGS, SBM had greater (P < 0.01) intestinal digestibility of rumen undegradable protein (RUP). Intestinally absorbable digestible protein (IADP) was greatest (P < 0.01) for CSM, with SBM and BCM having the least IADP. Total tract digestibility of CP (TTDP) was greater (P < 0.01) for SBM compared with CSM and DDGS. The contribution of RUP to intestinally absorbable AA was 7.2 and 3.1 g of lysine and methionine per kilogram of CP in BCM, respectively. The evaluation of B. carinata meal as protein supplemented for cattle consuming a forage-based diet resulted in 71.8% RDP and 97.1% TTDP, thus indicating its viability as a high-quality protein supplement for beef cattle.

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%.