Chemical and in vitro evaluation of Leucaena (Leucaena leucocephala) Leaves as a Substitute of Alfalfa (Medicago sativa L.) with/without Rejected Green Banana Fruits (Musa paradisiaca)

Leucaena leaves and rejected green banana fruits can be promising to cope with feed gaps in arid and semi-arid Mediterranean regions. The present study evaluated the feeding value and secondary active compounds of Leucaena leaves and rejected green banana fruits for ruminants using a semi-automated gas production (GP) system. Comparisons were made with the traditional feeds as alfalfa, and Dichanthium spp. grass hay. Analysis of HPLC was performed for the feed ingredients to characterize the main phenolic components. The in vitro evaluation was carried out for the experimental feed ingredients and diets. Four diets were formulated as the first diet consisted of alfalfa and grass hay at a ratio of 35:65 (AG), the second diet composed of alfalfa, grass hay, and green banana fruits at a ratio of 35:55:10 (AGB), third and fourth diets were prepared by replacing alfalfa in AG and AGB with Leucaena leaves to be LG and LGB, respectively. Leucaena leaves showed a high content of valuable phenolic components that have antioxidant and anti-inflammatory properties, such as gallic acid, ellagic acid, and naringenin. Moreover, Leucaena leaves and diet had higher crude protein, total phenols, and total tannins than alfalfa, which was reflected on the chemical composition of diets, and recorded the lowest total accumulative GP at 24 hours leading to low CH4 and CO2 production. Banana fruits recorded the lowest ruminal pH, ammonia concentration, and degraded neutral detergent fiber, compared to other feed ingredients, while it had the highest GP and degraded organic matter. Therefore, it is highly recommended to use Leucaena leaves in animals’ diets with/without rejected green banana fruits as an alternative feed resource with potential environmental and animal health benefits.

Effects of the Physiological Status and Diet on Blood Metabolic Parameters in Amiata Dairy Donkeys

Body weight changes and blood metabolic parameters in jennies feeding two different diets and in three physiological statuses were investigated (maintenance vs. pregnancy; maintenance vs. lactation). The relationships between blood metabolic profile and milk quality were also evaluated. Fourteen jennies were allocated to two groups (1: pregnant/lactating; 2: non-pregnant, non–lactating). Pregnant jennies and maintenance jennies (during the first 10-week measurement period) fed a diet consisted of ad libitum grass hay (diet 1); lactating jennies and maintenance jennies (during the last 10-week measurement period) fed ad libitum grass hay plus 2 kg/head/day of concentrate (diet 2). Blood sampling was performed on the jennies of both groups; individual milk samples were also collected during the first 70 days in milk. Higher blood NEFA (p < 0.05) were found in pregnant compared to maintenance jennies (diet 1) (68 vs. 37 µmol/L). Lactating jennies showed higher (p < 0.01) average blood NEFA (268 vs. 26 µmol/L) and glucose (66 vs. 55 mg/dL) compared to the maintenance (diet 2). Blood glucose was positively correlated to milk fat (p < 0.05), while negative significant correlations between de novo milk fatty acids and NEFAs were observed. Positive correlations between plasma B-HBA and somatic cell count (p < 0.01) were also found.

PSVIII-28 Dietary impacts on rumen, vaginal, and uterine environments in beef heifers

This experiment examined the effects of diet composition on rumen, vaginal, and uterine environments in beef heifers. Fifteen rumen-cannulated, pubertal Angus-influenced heifers were used in a replicated 3 x 3 Latin square design (28-d periods and 21-d washout intervals). Dietary treatments included (as-fed) diets based on 100% grass hay (HF), 61% grass hay + 39% corn-based concentrate (INT), or 25% grass hay + 75% corn-based concentrate (HG). Treatments were offered individually to heifers once daily at 2% of their body weight. Heifers also received 280 g/d of a mineral mix containing melengestrol acetate. Rumen, vaginal, and uterine fluid samples were collected on d 0 and 28 of each period for pH measurement. Data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) using results from d 0 as independent covariates, and heifer as the experimental unit. Rumen pH on d 0 did not differ (P = 0.97) among treatments (7.197, 7.194, and 7.188 for HF, INT, and HG, respectively; SEM = 0.038). Ruminal pH on d 28 was greater (P ≤ 0.01) in HF compared with INT and HG (6.805, 6.628, and 6.380, respectively; SEM = 0.049), and greater (P &lt; 0.01) in INT compared with HG. Vaginal and uterine pH on d 0 did not differ (P ≥ 0.24) among HF, INT, and HG (6.914, 6.965, 6.780 of vaginal pH, respectively, SEM = 0.082; 6.644, 6.760, 6,592 of uterine pH, respectively, SEM = 0.079). Uterine and vaginal pH on d 28 also did not differ (P ≥ 0.64) among HF, INT, and HG heifers (6.926, 6.937, 6.918 of vaginal pH, respectively, SEM = 0.051; 6.567, 6.507, and 6.457 of uterine pH, respectively, SEM = 0.084). Therefore, dietary composition impacted rumen pH of beef heifers as expected, but without consequences to their vaginal and uterine pH.

PSXI-16 Evaluation of supplementation strategies for beef cattle bale-grazing grass hay in Winter

Methods of supplementing beef cows while bale grazing grass hay were investigated in a study conducted for four winters, from 2016 to 2019, at the Central Grasslands Research Extension Center near Streeter, ND. Starting in the fall of each year, cows were assigned to eight groups of similar total body weight (BW) and allowed to bale graze one of four bale grazing treatments as follows: a) grass hay, b) grass hay supplemented with alfalfa hay, c) grass hay supplemented with corn DDGS, and d) grass hay treated with a liquid supplement. Two-day body weights and body condition scores (BCS) were taken at the start and end of the study. Final BW were greater (P ≤ 0.05) when cows were supplemented with DDGS and least when cows were not supplemented. Average daily gains were influenced by method of supplementation and year (P ≤ 0.025). When winters were cold, supplementation with alfalfa hay or a liquid supplement were not adequate to maintain cows resulting with weight loss. Final BCS were greatest (P ≤ 0.05) when cows were supplemented with DDGS and lowest on grass hay. Similarly, change in BCS was greatest in DDGS-supplemented cows and lowest on grass hay only. Calf birth weights, weaning weights and daily gains were not influenced (P &gt; 0.05) by method of supplementation. Results suggest that method of supplementation during bale grazing should be based on prevailing environmental conditions during winter. In severely cold winters, good-quality alfalfa hay or a liquid supplement are not adequate to meet requirements of pregnant beef cows in mid-gestation. Under such conditions, supplements such as corn DDGS will be needed to meet animal requirements. Supplementation with good-quality alfalfa hay or grass hay treated with a liquid supplement may be an option during mild winters.

Insects as Novel Ruminant Feed and a Potential Mitigation Strategy for Methane Emissions

This study is the first to evaluate the chemical composition and impacts of four different edible insects, Acheta domesticus (A.d), Brachytrupes portentosus (B.p), Gryllus bimaculatus (G.b), and Bombyx mori (B.m), on the digestibility, rumen fermentation, and methane production when used as a substitute for 25% of the soybean meal (SBM) in a ruminant diet through in vitro incubation. The dietary treatments were 100% grass hay, 60% grass hay + 40% SBM, 60% grass hay + 30% SBM + 10% A.d, 60% grass hay + 30% SBM + 10% B.p, 60% grass hay + 30% SBM + 10% G.b, and 60% grass hay + 30% SBM + 10% B.m. The experiment was conducted as a short-term batch culture for 24 h at 39 °C, and the incubation was repeated in 3 consecutive runs. Chemical analysis of the insects showed that they were rich in fat (14–26%) with a high proportion of unsaturated fatty acids (60–70%). Additionally, the insects were rich in protein (48–61%) containing all essential amino acids and the amino acid profiles of the insects were almost the same as that of SBM. The inclusion of insects did not affect nutrient digestibility or the production of volatile fatty acids but did increase the production of ammonia-nitrogen. The addition of G.b and B.m led to decrease in methane production by up to 18% and 16%, respectively. These results reveal that substitution of 25% SBM in the diet with the tested insects had no negative impacts, and their potential to reduce methane production is an environmental benefit.

Trace mineral source impacts rumen trace mineral metabolism and fiber digestion in steers fed a medium-quality grass hay diet

Twelve Angus steers (BW 452.8 ± 6.1 kg) fitted with ruminal cannulae were used to determine the impact of trace mineral (TM) source on digestibility, ruminal volatile fatty acid (VFA) composition, ruminal soluble concentrations of Cu, Zn, and Mn, and relative binding strength of trace minerals located in the rumen insoluble digesta fraction. Steers were fed a medium-quality grass hay diet (DM basis: 10.8% CP, 63.1% neutral detergent fiber [NDF], 6.9 mg Cu/kg, 65.5 mg Mn/kg, and 39.4 mg Zn/kg) supplemented with protein for 21 d. Treatments consisted of either sulfate (STM) or hydroxy (HTM) sources (n = 6 steers/treatment) to provide 20, 40, and 60 mg supplemental Cu, Mn, and Zn/kg DM, respectively. Following a 21-d adaptation period, total fecal output was collected for 5 d. Dry matter (P &lt; 0.07) and CP (P &lt; 0.06) digestibility tended to be reduced, and NDF (P &lt; 0.04) and acid detergent fiber (ADF) (P &lt; 0.05) digestibility were reduced in STM- vs. HTM-supplemented steers. On day 6, ruminal fluid was collected at 0, 2, and 4 h post-feeding and analyzed for VFA. There were no treatment x time interactions for VFA. Steers receiving HTM had less (P &lt; 0.02) molar proportions of butyric acid and greater (P &lt; 0.05) total VFA concentrations than STM-supplemented steers. Steers were then fed the same diet without supplemental Cu, Zn, or Mn for 14 d. On day 15 steers received a pulse dose of 20 mg Cu, 40 mg Mn, and 60 mg Zn/kg DM from either STM or HTM (n = 6 steers/treatment). Ruminal samples were obtained at 2-h intervals starting at −4 and ending at 24 h relative to dosing. There was a treatment x time interaction (P &lt; 0.03) for ruminal soluble Cu, Mn, and Zn concentrations. Ruminal soluble mineral concentrations were greater (P &lt; 0.05) for Cu at 4, 6, 8, 10, 12, and 14 h; for Mn at 4 and 6 h; and for Zn at 4, 6, and 8 h post-dosing in STM compared with HTM-supplemented steers. Copper concentrations were greater (P &lt; 0.05) at 12 and 24 h and Zn concentrations in ruminal solid digesta were greater at 24 h in HTM-supplemented steers. Upon dialysis against Tris-EDTA, the percent Zn released from digesta was greater (P &lt; 0.05) at 12 h (P &lt; 0.03) and 24 h (P &lt; 0.05), and the percent Cu released was greater (P &lt; 0.02) at 24 h post-dosing in HTM steers when compared with STM-supplemented steers. Results indicate that Cu and Zn from HTM have low solubility in the rumen and appear to be less tightly bound to ruminal solid digesta than Cu and Zn from STM. The lower ruminal soluble concentrations of Cu and Zn in steers given HTM were associated with greater fiber digestibility.

Ruminal degradation kinetics, intake, digestibility, and feeding behavior of beef steers offered annual or perennial grass-hay with or without supplementation

Effects of dried distillers grains plus solubles (DDGS) on ruminal fermentation, degradation kinetics, and feeding behavior of steers offered annual (Eragrostis tef; TEFF) or perennial (Bothriochloa bladhii; OWB) grass-hay were evaluated. Ruminally-cannulated Angus crossbred steers [n = 6; body weight (BW) = 304 ± 11 kg] were assigned to a 4 × 6 unbalanced Latin square design with 4 treatments arranged as a 2 × 2 factorial: hay type (OWB or TEFF) and DDGS supplementation {0 or 0.5% BW [dry matter (DM) basis]}. Steers had ad libitum access to hay. Periods consisted of a 14-d adaptation followed by 7 d of collection. Residues from the in situ incubations (0, 3, 6, 12, 24, 36, 48, 72, and 96 h post-feeding) were fitted to a first-order kinetics model using the NLIN procedure of SAS. The DDGS decreased (P &lt; 0.01) TEFF DM intake (DMI) by 11.3%, while not affecting DMI of OWB. The greatest DMI was observed for steers supplemented with DDGS, regardless of forage, and least in steers consuming OWB without DDGS (hay type × DDGS; P = 0.03). Non-supplemented steers spent more (P &lt; 0.01) time eating hay. Digestibility of DM tended (P = 0.06) to increase with DDGS supplementation. A hay type × DDGS interaction was observed (P ≤ 0.05) on ruminal effective degradable fractions. The rate of degradation, soluble fraction, and the potentially degradable fraction of OM, NDF, and ADF increased (P ≤ 0.05), while the undegradable fraction of all components decreased (P ≤ 0.01) when steers were offered TEFF compared to OWB. Ruminal DM, OM, and ADF degradation lag-time increased (P ≤ 0.02) in steers offered OWB. Ruminal degradation kinetics were not (P ≥ 0.17) independently affected by DDGS supplementation. Average ruminal pH of steers offered TEFF (P &lt; 0.01) and those offered DDGS (P &lt; 0.01) were lower than OWB and non-supplemented steers. Total concentration of VFA tended (P = 0.09) to increase when DDGS was provided with OWB, while decreasing when TEFF was offered. The acetate:propionate increased (P &lt; 0.01) with DDGS supplementation due to a decrease (P = 0.03) in propionate. Ruminal NH3-N was greater (P = 0.03) in steers offered TEFF compared to OWB, and those supplemented with DDGS (P = 0.03). An annual, in place of a conventional, perennial hay improved intake and digestion of nutrients, without affecting feeding behavior. The supplementation with DDGS appears to affect forage intake, ruminal degradation, and feeding behavior, although not independent of forage quality.