Total Mixed Ration Research Articles

PSI-1 Assessing the Impact of Hempseed Meal Supplementation on Inflammatory Cytokine Concentrations in Boer X Spanish Intact Male Goats

Abstract This study aimed to evaluate the effect of hempseed meal (HSM) supplementation on the concentrations of inflammatory cytokines in intact male goats. Effect on the concentration of pro-inflammatory cytokines, interleukin (IL) 2 , IL-6, tumor necrosis factor-alpha (TNF-α), and interferon-gamma (INF-γ) and anti-inflammatory cytokines,; IL-4 and IL10, were evaluated via chicken-ovalbumin challenge. Thirty-six Boer x Spanish intact male goats, 10 to 11 months of age and bodyweights of 44.1 ± 3.8 kg, were randomly assigned to one of the four experimental diets (n = 9 goats/diet): 0% (control), 10%, 20%, and 30% HSM diets and fed ad libitum for 60 days. Experimental diets were formulated as total mixed ration (TMR), and the nutrient content of each diet was formulated to be iso-nitrogenous (18% crude protein) and to meet or exceed the nutrient requirement of breeding male goats. On day 46, goats were injected subcutaneously with chicken ovalbumin (2.5 mg) prepared in saline solution and alhydrogel as an adjuvant. On 14 days of post-injection, serum samples were collected and analyzed for cytokines concentrations using an indirect enzyme-linked immunosorbent assay. Data were analyzed using one-way ANOVA and Kruskal-Wallis test using R version 4.2.1. Results show no significant difference (P > 0.05) among the experimental groups in terms of studied pro-inflammatory cytokines (IL-2, IL-6, TNF-α, and INF-γ) as well as anti-inflammatory cytokines (IL-4 and IL-10) concentrations (Table 1). Results indicate that the inclusion of HSM up to 30 % in the diet does not affect the production of pro-inflammatory and anti-inflammatory cytokines in intact male goats. This study provides valuable insights into the impact of HSM supplementation on inflammatory response in goats.

PSXIV-12 Evaluation of an Ensiled, Self-Fed Diet for Backgrounding Beef Cattle

Abstract Self-feeding of ensiled forages consists in allowing the animals to feed from the silo face through a physical barrier. Energy, protein, and mineral supplements are offered separately in free-choice portable feeders. Compared with offering a total mixed ration, the self-feeding system could result in differences in ensiled forage and supplement intake and may increase animal performance variability. Ensiling a complete diet may contribute to overcome these drawbacks. This study compared the performance of calves that consumed an ensiled backgrounding diet from a silo-bag face (self-feeding, SF) with that of calves fed a diet mixed and delivered daily in a feed bunk (TMR). A single forage sweet sorghum crop was harvested and bagged to be used in the TMR treatment, or harvested and added a dry supplement (45% finely-ground corn grain, 50% extruded soybean meal, and 5% vitamin-mineral premix without ionophore) during bagging, using an adjustable-discharge hopper mounted above the bagger’s packing rotor, to be used in the SF treatment. Regardless of treatment, the diet consisted of 61% forage sorghum and 39% dry supplement (DM basis; 9.9 and 11.6% CP, 42.3 and 43.8% NDF, and 9.8 and 9.5% starch for TMR and SF diets, respectively). Bagged feeds were allowed to ensile for 50 d before experiment began. Two hundred fifty-two, non-implanted Angus calves (224 ± 4.6 kg) were blocked by body weight (BW) and coat color resulting in 6 blocks and 1 pen/block per treatment with 12 or 30 animals per TMR or SF pen, respectively; more animals were required in the SF pens to maintain feed fresh and reduce spoilage, though BW was measured on 12 calves. Pens assigned to SF treatment were each equipped with a silo bag blocked off with an iron fence. The TMR animals were fed ad libitum once a day. In SF pens, feed was carved from the silo-bag face manually twice daily using a pitchfork onto a pile on the fence’s bag side. Cattle were fed for 70 d and held off feed and water for 16 h to record initial (day 1) and final BW (day 70). Data were analyzed as a randomized complete block design. Rate of BW gain, DMI, and DMI relative to BW were greater (P < 0.01; Table 1) for SF calves compared with TMR, resulting in greater (P = 0.03) final BW but similar (P = 0.36) ADG:DMI. Coefficient of variation (CV) of final BW and ADG and the increase in CV of BW did not differ (P ≥ 0.93) between treatments. Similar feed efficiency and animal performance variability were achieved by feeding an ensiled ration offered in a self-feeding system or a traditional TMR. The former might represent a simple and feasible feeding alternative for small-size beef cattle operations.

PSII-27 Inflammation- and Immunity-Associated Gene Expression in the Liver and Whole Blood of Crossbred Beef Cattle with Divergent Residual Feed Intake Phenotype

Abstract We investigated the inflammation- and immunity-associated gene expression in the liver and whole blood of crossbred beef cattle with divergent residual feed intake phenotype to identify relevant immune-related biological processes underpinning feed efficiency in beef cattle. Low-RFI beef steers (n = 8; RFI = - 1.93 kg/d) and high-RFI beef steers (n = 8; RFI = + 2.01kg/d) were selected from a group of 56 growing crossbred beef steers (average BW = 261 ± 18.5 kg) fed a high-forage total mixed ration after a 49-d performance testing period. At the end of the 49-d testing period, liver biopsies and blood samples were collected for total RNA extraction and cDNA synthesis. The mRNA expression of 84 genes each related to innate and adaptive immunity was analyzed using pathway-focused PCR-based arrays. The mRNA expressions of genes with fold change ≥ (-) 2.0 and FDR ≤ 0.05 in the blood and liver were determined to be differentially expressed. Out of the 84 immune genes analyzed, the expression of 8 genes in the blood and 20 genes in the liver were upregulated in low-RFI, compared with high-RFI steers. Gene ontology analysis of all the differentially expressed genes in the blood and liver revealed that pathways related to pattern recognition receptor activity, detection of lipopolysaccharide, detection of external biotic stimulus, positive regulation of phagocytosis, positive regulation of vitamin metabolic process, vascular endothelial growth factor production, positive regulation of epithelial tube formation and T-helper cell differentiation were enriched (FDR < 0.05) in Low-RFI beef steers. These results suggest that low-RFI steers have a robust immune repertoire that is capable of prompt response to inflammatory stimuli. This prompt response to inflammation in the Low-RFI group may be characterized by greater protein turnover and increased epithelial cell differentiation, whereby an enhanced quantity of invariant natural killer T-cells and viability of natural killer cells could induce a quicker and more effective response to inflammatory stimuli and consequently contribute to more efficient partitioning of nutrients for growth in these animals.

358 The Effects of Varying Levels of Cotton Gin Byproduct and Wet brewers’ Grains on Growth Performance of Growing and Finishing Steers

Abstract The abundance of craft breweries provides widespread availability of wet brewers grains (WBG) to be used by beef cattle producers as a potential feedstuff. Cotton gin byproduct (CGB) is a feedstuff typically reserved for mature beef cows due to its low and variable feed value. Both WBG and CGB have high cost of transportation but are sometimes used by producers near supply centers due to their low price. The objective of this study was to analyze animal performance of growing Angus steers fed total mixed rations with varying amounts of CGB and WBG. Sixty-four Angus steers (365 ± 26 kg) were allotted and blocked by initial body weight (BW) in a randomized complete block design to 8 dietary treatments and fed in 2 phases, growing phase (GP) and finishing phase (FP) (84-d and 69-d, respectively). Dietary treatments were arranged in a 2 x 4 factorial with two levels of CGB (0 or 25% of DM) and 4 levels of WBG (0, 10, 20 or 30% of DM). The control and base of all treatments were corn, corn silage and soybean meal. Body weights were recorded on two consecutive days at the beginning and end of GP and FP. Feed samples were collected, and refusals were weighed weekly. Data were analyzed using the MIXED procedure of SAS 9.4 with main effects of CGB, WBG, and the interaction. The linear, quadratic, and cubic effects of increasing levels of WBG and CGB were tested with polynomial contrasts. Average daily gain (ADG) did not differ among dietary treatments (0, 25% CGB and 0, 10, 20, 30% WBG) for GP, (1.67, 1.61, and 1.67, 1.57, 1.74, and 1.60 kg/d, respectively) (P > 0.3031), FP (1.53, 1.61 and 1.56, 1.53, 1.61, and 1.58 kg/d) or the overall trial (1.61, 1.62 and 1.62, 1.55, 1.68, and 1.60 kg/d). The addition of CGB increased GP dry matter intake (DMI; 11.06 vs 11.99 kg/d; P = 0.0011), while the addition of WBG linearly decreased GP DMI (11.81, 11.69. 11.81, and 10.81 kg/d; P = 0.0292). There was an interaction between CGB and WBG (P = 0.0206), with increasing levels of WBG at 0% CGB exhibiting a cubic effect (P = 0.0127), but no effect at 25% CGB. Inclusion of CGB decreased feed efficiency (FE) in the GP (6.77 vs. 7.69; P = 0.0008) but had no carry-over effect in the FP. There was no effect of WBG on FE in GP or FP. In conclusion, CGB increased DMI, reduced FE, and maintained ADG. Increasing quantities of WBG did not reduce ADG or FE, but decreased DMI with increasing feeding level. Therefore, WBG and CGB can be considered viable options for cattle producers seeking to lower input costs.

403 Awardee Talk: Characterization of Rumen Microbiome and Immune Genes Expression of Crossbred Beef Steers with Divergent Residual Feed Intake Phenotypes

Abstract We investigated whole blood and hepatic mRNA expressions of immune genes and rumen microbiome of crossbred beef steers with divergent residual feed intake (RFI) phenotype to identify relevant biological processes underpinning feed efficiency in beef cattle. Low-RFI beef steers (n = 20; RFI = - 1.83 kg/d) and high-RFI beef steers (n = 20; RFI = + 2.12 kg/d) were selected from a group of 108 growing crossbred beef steers (average BW = 282 ± 30.4 kg) fed a high-forage total mixed ration after a 70-d performance testing period. At the end of the 70-d testing period, liver biopsies and blood samples were collected for total RNA extraction and cDNA synthesis. Rumen fluid samples were also collected for analysis of the rumen microbial community. The mRNA expression of 84 genes related to innate and adaptive immunity was analyzed using pathway-focused PCR-based arrays. Differentially expressed genes were determined using P-value ≤ 0.05 and fold change (FC) ≥ 1.5 (in whole blood) or ≥ 2.0 (in liver). Gene ontology analysis of the differentially expressed genes revealed that pathways related to pattern recognition receptor activity, positive regulation of phagocytosis, positive regulation of vitamin metabolic process, vascular endothelial growth factor production, positive regulation of epithelial tube formation and T-helper cell differentiation were significantly enriched (FDR < 0.05) in low-RFI steers. In the rumen, the relative abundance of PeH15, Arthrobacter, Moryella, Weissella and Muribaculaceae was enriched in low-RFI steers, while Methanobrevibacter, Bacteroidales_BS11_gut_group, Bacteroides and Clostridium_sensu_stricto_1 were reduced. Our study found that low-RFI beef steers exhibit increased mRNA expression of genes related to immune cell functions in whole blood and liver tissues, specifically those involved in pathogen recognition and phagocytosis regulation. Additionally, these low-RFI steers showed differences in relative abundance of some microbial taxa which may partially account for their improved feed efficiency compared with high-RFI steers.

242 Methionine and Guanidinoacetic Acid Supplementation During the Periconceptual Period of Gestation Shifts Methionine Metabolism of Fetal Bull Calves at D 63 of Gestation

Abstract Recent research has demonstrated that feeding rumen protected methionine (MET) products increases circulating methionine while feeding guanidinoacetic acid (GAA) may result in a methyl deficiency. Therefore, we hypothesized that maternal MET or GAA supplementation from 63 days before breeding until d 63 of gestation would increase fetal hepatic methyl donors or result in a fetal hepatic methyl donor deficiency, respectively. Eighty MARC II heifers (n = 20 per treatment; initial BW = 344 ± 8 kg; day -63) were weighed and assigned to one of four breeding groups and four treatments stratified by age and starting weight. Heifers were fed a total mixed ration to gain 0.68 kg/d and received 100 g of one of four treatments top dressed: control supplement of ground corn (CON), MET (10 g/d) in a ground corn carrier, GAA (40 g/d) in a ground corn carrier, or MET + GAA (10 g/d MET + 40 g/d GAA) in a ground corn carrier. At breeding (d 0), all heifers were bred to a single sire using male sexed semen. At d 63 of gestation, 35 heifers (CON n = 10, MET n = 8, GAA n = 7, MET + GAA, n = 10) confirmed pregnant with bull calves were humanely slaughtered and fetal liver tissues were collected and sent to Metabolon Inc. for global metabolomics analysis. Data were analyzed as a 2 x 2 factorial with 2 levels of GAA and 2 levels of MET with breeding group included in the model. For this abstract, only metabolites from the methionine cycle and adjacent pathways will be reported and only metabolites with significant P-values will be discussed (P ≤ 0.05). There were no main effects or interactions for the abundance of methionine, GAA, creatine, SAM, SAH or homocysteine. Glycine was decreased and sarcosine increased in fetuses from MET supplemented dams. Serine was affected by a MET x GAA interaction being decreased in livers of CON, MET, and MET + GAA fetuses compared with GAA. Cystathione, S-methylcysteine, s-methylcysteine sulfoxide, and hypotaurine were greater in fetuses of MET supplemented heifers and pyridoxal phosphate was reduced in fetal liver of MET supplemented heifers. The abundance of urea was greater in GAA supplemented fetuses. These results indicate that fetuses from dams fed methionine may be able to maintain balance in methionine supply by shunting methionine through adjacent pathways including the transsulfuration pathway. We also interpret these data to imply that excess methionine is not utilized by the fetus and is metabolized to products that can be excreted. Lastly, GAA did not alter the fetal methyl supply. USDA is an equal opportunity provider and employer. Funded by (USDA-NIFA-AFRI # 2022-67015-36196).

Effect of Rearing System and Physical form of the Total Mixed Ration on Growth Performance of Local Male Lambs

The University of Anbar’s Department of Animal Production hosted this experiment on their sheep farm from October 18, 2022, through January 6, 2023. Twenty-two local male lambs, ranging in age from 3.3 to 3.5 months, and averaging 20.2±2.28 kilograms were included. The purpose of the experiment was to determine the influence of the rearing system and physical form of the total mixed ration on the growth and feeding performance of local male lambs. Lambs were randomly distributed into four treatments. T1 (group housing + loose diet) included 6 Lambs distributed in three group cages (2 Lambs /cage), T2 (group housing + pellet diet) included 6 Lambs distributed in three group cages (2 Lambs /cage), T3 (individual housing + loose diet) included 5 Lambs distributed in five individual cages (1 lamb / cage), and T4 (individual housing + pellet diet) included 5 Lambs distributed in five individual cages. A total of 63 days were devoted to the actual experiment. All lambs were fed ad-libitum to the Pelleted and loose total mixed ration. Throughout the duration of the experiment, the parameters of growth and nutritional performance were estimated. The results of present experiment showed that the individual rearing system significantly improved daily feed intake and dry matter intake compared with grouped rearing system. The pelleted total mixed ration was superior to the loose total mixed ration in growth performance (final body weight, total weight gain, daily weight gain) and feeding performance (feed conversion ratio, feeding efficiency), and decreased the cost of producing 1 kg of weight gain. The results showed that the growth and feeding performance of local male lambs were significantly boosted by the interaction between individual housing and pellet diet. Researchers found that fattening lambs’ productivity might be improved with the use of individual housing combined with a pellet diet.

Effects of different feeding systems on ruminal fermentation, digestibility, methane emissions, and microbiota of Hanwoo steers.

This study evaluates how different feeding systems impact ruminal fermentation, methane production, and microbiota of Hanwoo steers native to Korea. In a replicated 2 × 2 crossover design over 29 days per period, eight Hanwoo steers (507.1 ± 67.4 kg) were fed twice daily using a separate feeding (SF) system comprising separate concentrate mix and forage or total mixed rations (TMR) in a 15:85 ratio. The TMR-feeding group exhibited a considerable neutral detergent fiber digestibility increase than the SF group. However, ruminal fermentation parameters and methane production did not differ between two feeding strategies. In addition, TMR-fed steers expressed elevated Prevotellaceae family, Christensenellaceae R-7 group, and an unidentified Veillonellaceae family genus abundance in their rumen, whereas SF-fed steers were rich in the Rikenellaceae RC9 gut group, Erysipelotrichaceae UCG-004, and Succinivibrio. Through linear regression modeling, positive correlations were observed between the Shannon Diversity Index and the SF group's dry matter intake and methane production. Although feeding systems do not affect methane production, they can alter ruminal microbes. These results may guide future feeding system investigations or ruminal microbiota manipulations as a methane-mitigation practice examining different feed ingredients.

Design and Testing of Segmented Spiral Total Mix Ration Mixer

To address the challenges of non-uniform mixing in total mixed diet forage and the high power consumption of the required device, we developed a segmented spiral total mixed diet device. This development involved theoretical analysis to determine the structural parameters of the main body of the segmented spiral blades, the churn, and the creation of a test bed for the segmented spiral total mixed diet device. Taking mixing speed, mixing time, filling coefficient, and segmented spiral blade spacing as test factors and mixing uniformity and energy consumption per unit mass as test indexes, the optimal combination of operating parameters of the device was determined by using a four-factor, three-level orthogonal test method. The results of the validation test showed that the mixing uniformity of the device under these conditions was 93.41%, the energy consumption per unit mass was 4723.69 J, and the errors between the mixing test values of the device and the optimized values of the model were all less than 5%. This study can provide a reference for improving the working quality of the segmented spiral TMR mixer.

Identifying the Influence of the Dietary Polyunsaturated Fatty Acid Content on Milk Quality Traits in Najdi Sheep at Different Stages of Lactation

The quality of milk is fundamental to producing safe milk and dairy products that are suitable for consumption. The objective of this study was to determine the influence that the content of dietary polyunsaturated fatty acids (PUFA) has on the total mixed ration (TMR) and lactation stage of milk’s composition and the fatty acid profile (FA) of the dairy Najdi breed. During the lactation period, 48 Najdi ewes used the following four treatments: traditional feed (TR) and three total mixed rations (TMR1, TMR2, and TMR3) with different PUFA content. Milk samples were taken from whole milk in the morning. The chemical composition and FA profile were analyzed. The results show that the ewes fed TMR1 with a PUFA content (25.20%) produced high-quality milk as they contained high levels of polyunsaturated fatty acids (PUSF), linoleic acid (LA), α-linolenic acid (ALA) and omega-3 (n3). On the other hand, the milk of ewes fed TMR2 with PUFA (15.06%) contained high levels of unsaturated fatty acids (USF) and monounsaturated fatty acids (MUFA) and had significantly reduced hypercholesterolemia (HFA). It can be concluded that milk fat, protein, and total solids in the milk of Najdi sheep increased as lactation progressed, while lactose remained constant. Furthermore, as lactation progressed, saturated fatty acids (SFA), stearic acids, and oleic acids (OA) increased while USF and MUFA decreased. TMR diets can directly benefit the producer and livestock by producing high-quality milk while reducing its economic value.

37 Effects of Creep Feeding Duration on Rumen Fermentation Characteristics Using an Ex Vivo Model

Abstract The objective was to determine the effects of creep feeding duration on ruminal fermentation using an ex vivo model. Simmental × Angus, spring-born calves (n = 72) were stratified by age (83 ± 14 d) and body weight (BW) into 12 pens with 6 calves per pen. Pens were randomly assigned to 1 of 2 treatments: calves fed creep for 105 d (105dCF) or final 21 d (21dCF) before weaning. Cow-calf pairs were housed on concrete drylots with open-front buildings. Cows were limit-fed at maintenance a total mixed ration (TMR) that consisted of corn, grain coproducts, and corn stalks. Calves (n = 16) were utilized for ex vivo experiments. Experiment 1 was conducted on d 76, before the 21dCF calves having access to creep feed. Rumen fluid was collected from 8 calves per treatment via esophageal tubing and mixed with McDougall’s buffer (1:2 ratio). Each rumen fluid inoculum was combined with 2 substrates (cow TMR or creep feed) in a split-plot design and incubated for 24 h at 39°C. Data were analyzed using the MIXED procedure of SAS 9.4. In Exp. 1, there was no creep feeding duration by substrate interaction (P ≥ 0.16) for 24-h pH, butyrate, acetate, or IVDMD. Molar proportions of acetate and butyrate were greater (P ≤ 0.001) for the 105dCF calves than for the 21dCF calves. There was a treatment by substrate interaction (P = 0.02) for total VFA. The 105dCF calves had greater total VFA than 21dCF calves with a greater magnitude of difference observed with TMR substrate. Calves on 105dCF had greater (P < 0.01) IVDMD than 21dCF calves regardless of substrate (64% and 59%, respectively). Experiment 2 was conducted on day 105 after all calves were abruptly weaned and transported 263 km to the feedlot. Procedures were similar to Exp. 1, except substrates included creep feed and feedlot receiving diet. In Exp. 2, no treatment by substrate interaction (P ≥ 0.13) was observed for 24-h pH, acetate, propionate, total VFA, or IVDMD. Although acetate was greater (P < 0.01) for the 105dCF calves, propionate was greater (P < 0.01) for the 21dCF calves. There was no treatment effect (P = 0.57) for total VFA; however, it was greater (P < 0.01) for the creep feed substrate than for the receiving diet substrate. In Exp. 2, IVDMD tended to be greater (P = 0.06) for 21dCF calves than 105dCF calves. In conclusion, results indicated creep feeding improved ruminal fermentation ex vivo, but even a short-term creep feeding duration of 21 d appears to be adequate in preparing rumen microbial community to degrade the receiving diet as there were fewer differences in rumen fermentation characteristics at feedlot arrival.

97 Effects of Creep Feed Duration in a Drylot System on Cow Performance and Reproduction as Well as Calf Performance Through Receiving

Abstract The objectives were to determine effects of creep feed duration in drylot-housed, cow-calf system on cow performance and reproduction as well as calf performance through receiving phase. Spring-calving, Simmental × Angus cows (5 ± 2 yr; n = 72) were stratified by calf age (83 ± 14 d), sex, and body weight (BW; 130 ± 17 kg) and allotted to 12 pens with six cow-calf pairs per pen. Pens were randomly assigned to 1 of 2 treatments: calves fed commercial, pelleted creep feed (14% CP) for 105 d (105dCF) or final 21 d (21dCF) prior to weaning. Cow-calf pairs were housed on concrete drylots with open-front buildings for the pre-weaning period. Cows were limit fed at maintenance a total mixed ration. Ultrasound measurements for carcass composition of calves were collected on d 104. Calves were abruptly weaned on d 105 and transported 263 km to a feedlot for the receiving phase. Pen assignments remained for the 6-week receiving period. Calves had ab libitum access to a receiving ration that consisted of corn silage, modified wet distillers grains, grass hay, dry corn, and supplement. Reproduction data were analyzed using GLIMMIX and all other response variables were analyzed using the MIXED procedure of SAS 9.4. There were no differences (P ≥ 0.11) in cow BW, BCS, milk production, milk composition, or reproductive data. The 105dCF calves had greater (P ≤ 0.01) ADG from d 0 to 105 and BW than 21dCF (286 vs. 258 kg, respectively). The 105dCF calves had greater (P ≤ 0.01) longissimus muscle area, rib fat, and rump fat compared with 21dCF; however, intramuscular fat was not different (P = 0.20) between treatments. During the receiving phase, there were no differences (P ≥ 0.23) in dry matter intake. In the first 4 weeks of receiving there were no differences (P ≥ 0.73) in ADG; however, in the final 2 weeks 21dCF calves had greater (P = 0.02) ADG. The 21dCF calves had greater (P = 0.01) ADG during the overall receiving period. There were no differences (P ≥ 0.86) in gain to feed (G:F) for the first four weeks of receiving. The 21dCF calves had greater (P = 0.03) G:F for the final two weeks and tended to have greater (P = 0.08) G:F during overall receiving. However, the 21dCF calves (324 kg) were still lighter (P ≤ 0.01) BW than 105dCF (340 kg) at end of receiving. In conclusion, creep feed duration did not impact cow performance or reproduction. The 105dCF calves had increased ADG and BW for the pre-weaning period. Although the 21dCF calves had increased gain and feed efficiency at the end of receiving, the 105dCF calves remained the heavier for the duration of the experiment.

Hepatic metabolism of grazing cows of two Holstein strains under two feeding strategies with different levels of pasture inclusion.

The objective of the study was to characterize adaptations of hepatic metabolism of dairy cows of two Holstein strains with varying proportions of grazing in the feeding strategy. Multiparous autumn calving Holstein cows of New Zealand (NZH) and North American (NAH) strains were assigned to a randomized complete block design with a 2 x 2 factorial arrangement with two feeding strategies that varied in the proportions of pasture and supplementation: maximum pasture and supplementation with a pelleted concentrate (MaxP) or fixed pasture and supplementation with a total mixed ration (FixP) from May through November of 2018. Hepatic biopsies were taken at - 45 ± 17, 21 ± 7, 100 ± 23 and 180 ± 23 days in milk (DIM), representing prepartum, early lactation, early mid-lactation and late mid-lactation. The effects of DIM, feeding strategy (FS), strain and their interactions were analyzed with mixed models using repeated measures. Cows of both strains had similar triglyceride levels, mitochondrial function and carnitine palmitoyltransferase activity in liver during lactation. However, there was an effect of DIM and FS as liver triglyceride was higher for the MaxP strategy at 21 DIM and both mitochondrial function and carnitine palmitoyltransferase activity in liver were lower for the MaxP strategy at 21 DIM. Hepatic mitochondrial function and acetylation levels were affected by the interaction between strain and feeding strategy as both variables were higher for NAH cows in the MaxP strategy. Mid-lactation hepatic gene expression of enzymes related to fatty acid metabolism and nuclear receptors was higher for NZH than NAH cows. This work confirms the association between liver triglyceride, decreased hepatic mitochondrial function and greater mitochondrial acetylation levels in cows with a higher inclusion of pasture and suggests differential adaptative mechanisms between NAH and NZH cows to strategies with varying proportions of grazing in the feeding strategy.

Qualitative evaluation of total mixed ration silage containing forage cactus and guinea grass as a nutritional alternative for feedlot-finished sheep

ABSTRACT This study aimed to evaluate the fermentation characteristics, microbial populations, losses, aerobic stability and chemical composition of total mixed ration based on forage cactus and different ratios of Guinea grass at four storage times (7, 15, 60 and 100 days). Five diets were formulated with forage cactus as the main ingredient, with varying Guinea grass inclusion ratios: 0, 10, 20, 25 and 30% on a dry matter basis. The experimental design used was a completely randomised design with a factorial arrangement and three replicates. The silages had pH values of approximately 4.0. Lactic acid bacteria were predominant in all silages, and this predominance increased after 7 days of ensiling in all diets, ranging from 8.0–10.1 log10 cfu g−1 of silage. Silages with 10% and 20% guinea grass showed aerobic deterioration, while the others remained stable throughout the aerobic stability test. Guinea grass in combination with forage cactus can be added in total mixed ration silages up to a level of 30%, without compromising the chemical composition, silage losses or fermentative profile. However, considering aerobic stability, the addition of 10% and 20% guinea grass resulted in greater deterioration after 48 h of exposure to air.

Biochemical methane potential of dairy manure residues and separated fractions: An Australia-wide study of the impact of production and cleaning systems

This study investigated biochemical methane potential (B0) of manure residues and solid–liquid separation fractions from Australian dairies. This is important for country-specific sector emissions and biogas potential estimates. A range of samples were collected from 12 farms across 4 Australian states, and B0 was measured. A first B0 value for grazing dairy effluent is reported, at 161 LCH4·kgVS-1. The B0 of manure residues from intensive dairies with total mixed ration feeding was not significantly different, at 202 LCH4·kgVS-1. Passive solid–liquid separation decreased B0 with potential fugitive methane losses. Mechanical separation preserved B0, allowing organic matter diversion to reduce fugitive methane emissions. Cleaning method at a dairy significantly influenced residue total solids content, important for solid–liquid separation and selection of anaerobic digestion technology. Overall, B0 for Australian dairy residues was estimated at 76.2 million m3N methane per annum, with a total energy content of 2.8 petajoules·annum−1.

Assessment of the Effects of Commercial or Locally Engineered Biochars Produced from Different Biomass Sources and Differing in Their Physical and Chemical Properties on Rumen Fermentation and Methane Production In Vitro.

In recent years, interest in using biochar as feed additives to mitigate enteric methane (CH4) emissions from ruminants has increased. It has been suggested that the mitigating potential of biochar is influenced by its physical (e.g., porosity-related) and chemical (e.g., redox-potential-related) properties. Thus, the aim of this in vitro study was to evaluate the effects of commercial or locally engineered biochars, produced from different biomass sources and differing in their physical and chemical characteristics, on rumen fermentation and CH4 production. For this purpose, a 24 h batch culture of ruminal fluid incubations was conducted in a complete randomized block design (repeated three times) that included a negative control (no additive), a positive control (monensin, 10 mg/mL), and four commercial and three locally engineered biochars, each evaluated at 1%, 2%, or 5% of the substrate's (i.e., the total mixed ration) dry matter. The evaluated biochars greatly differ in their chemical (i.e., moisture, ash, pH, redox potential, volatiles, carbon, fixed carbon, hydrogen, and sulfur) and physical (i.e., fine particles < 250 µm, bulk density, true density, porosity, electrical conductivity, specific surface area, and absorbed CO2) properties. Despite these differences and compared with the negative control, none of the biochars evaluated (regardless of the inclusion rate) influenced gas and CH4 production, volatile fatty acid characteristics (total concentration and profile), or ammonia-nitrogen (NH3-N) concentrations. As expected, monensin (i.e., the positive control) decreased (p < 0.05) CH4 production mainly because of a decreased (p < 0.05) acetate-to-propionate ratio. The results of this study reveal that despite the large differences in the physical and chemical properties of the biochars evaluated, their inclusion at different rates in vitro failed to modify rumen fermentation and decrease CH4 production. Based on these in vitro findings, it was concluded that biochar does not represent a viable strategy for mitigating enteric CH4 emissions.

Self-fermented agro-wastes as antioxidant enriched maize grain replacer for sustainable animal feeding

Piles of agro-wastes resulting from quantum agro-industrial growth can be best utilized as animal feed, reducing envionmental impact by 50–95% depending on their nutritive value. However, palatability issues have limited their use, which can be addressed by combining them based on their nutritional value. Thus present three-phase study aimed to utilize these waste materials as animal feed by utilizing a self-fermentation approach. Six combinations of apple pomace (AP), spent mushroom compost (SMC) and wheat straw were self-fermented and analysed for quality in phase-I. Phase-II assessed the best combination obtained from phase-I as an antioxidant-enriched maize replacer (AEMR) by replacing maize (0–32%) in total mixed ration (TMR) under in-vitro ruminal conditions and two best TMR were assessed for nutrient utilization under metabolic trial. In phase-III, the three-month feeding effect of AEMR on the overall growth performance of male Gaddi goat kids was assessed. Findings showed that 85:7.5:7.5 proportion had optimal pH (3.92), significantly higher lactic acid (5.29 g 100−1 g DM), water soluble carbohydrates (2.29 g 100−1 g DM) and oxidative and microbial stability (Lactobacillus: 8.38 log10 cfu g−1). Fermentation also resulted in significant increase in antioxidant activities. AEMR exhibited a significant reduction in CH4 and NH3–N and higher volatile fatty acid production under in-vitro conditions at 32% level with no adverse effects on nutrient utilization. AEMR feeding also exhibited significantly improved feed conversion ratio (FCR) and serum lipid and oxidative profiles. In conclusion, AP and SMC in combined form can be utilized as an AEMR through self-fermentation at 32% level in TMR which may serve as a promising and sustainable approach for reducing environmental footprints and boosting eco-friendly livestock production.

Peripartum factors associated with variation in voluntary postpartum hay intake in dairy cows

The objective of this research was to assess variation in postpartum hay intake when offered alongside total mixed ration (TMR) as free choice, and identify factors related to the hay intake. Twenty multiparous cows were fed a closeup TMR (21.5% starch, 39.1% neutral detergent fiber [NDF] on a dry matter [DM] basis). After calving, cows were offered free choice timothy hay (61.6% NDF, 9.6% crude protein) in addition to a fresh cow TMR (26.8% starch, 33.0% NDF) for the first 5 d postpartum. Cows were fed individually with separate mangers for TMR and hay, each offered ad libitum. Prepartum DM intake (DMI) was recorded, and baseline blood samples were collected after calving, but before the first postpartum feeding. Free choice hay intake ranged from 0 to 4.7 kg/d (DM basis) or 0 to 55.2% (% of total DMI). Cows that consumed more hay (% of total DMI) from d 1 through 5 postpartum had lower DMI 2 d before calving (r = −0.63), and greater baseline concentrations of plasma β-hydroxybutyrate (r = 0.60) and serum haptoglobin (r = 0.68). Additionally, hay intake (% of total DMI) from d 1 through 5 postpartum tended to be positively related to baseline plasma fatty acid concentration (r = 0.41). These findings suggest that cows with lower intake before calving and cows with greater ketone production and inflammation at calving may consume more hay, when offered separate from TMR.

Effect of exogenous fibrolytic enzymes cocktail incorporation on in vitro degradation and fermentation characteristics of oats straw based total mixed ration

The study was conducted to evaluate the effects of increasing doses: 0 (control), 0.20, 0.40, 0.60, 0.80 and 1.00 % DM of an exogenous fibrolytic enzymes (EFE) cocktail preparation on in vitro gas production (GP), nutrient degradability and fermentation characteristics of oats straw based Total Mixed Ration (TMR) with 60:40 roughage to concentrate ratio using sheep rumen liquor. The chemical composition of all the feed ingredients used for preparation of the experimental TMR (containing 16.63% crude protein and 90.51% organic matter) were within the normal ranges. Increasing the incorporation level of enzyme cocktail linearly as well as quadratically increased net GP, metabolisable energy content, short chain fatty acid concentrations and microbial crude protein production up to 0.60% DM level (L3) with no additional improvement at further higher levels. There were significant improvements in degradability of dry matter, organic matter and neutral detergent fibre up to the enzyme dose of 0.60% DM (L3) with constant values thereafter. Fermentation characteristics response to varying incorporation doses of EFE cocktail also revealed improvements up to 0.60% DM level (L3) with no effect on non-protein nitrogen contents. It is recommended that EFE cocktail incorporation dose of 0.60% DM to be used for efficient utilisation of oats straw based complete feed; however, this requires further testing by in vivo studies.

Leverage of Essential Oils on Faeces-Based Methane and Biogas Production in Dairy Cows

Currently, there is an ongoing intensive search for solutions that would effectively reduce greenhouse gas emissions (mainly methane) into the environment. From a practical point of view, it is important to reduce methane emissions from cows in such a way as to simultaneously trim emissions from the digestive system and increase its potential production from feces, which is intended as a substrate used in biogas plants. Such a solution would not only lower animal-based methane emissions but would also enable the production of fuel (in chemical form) with a high yield of methane from biogas, which would boost the economic benefits and reduce the use of fossil fuels. We tested the effect of administering an essential oil blend consisting of 5.5% oils and fats on methane and biogas production from dairy cow feces during fermentation. Three subsequent series (control and experimental) were conducted in dairy cows fed a total mixed ration (TMR) rich in brewer’s cereals and beet pulp, with 20% dry matter (DM) of the total diet. Cows from the experimental group received 20 g/cow/day of essential oil blend, namely a commercial additive (CA). The study showed that CA can increase the production of methane and biogas from dairy cow feces. It can be concluded that in the experimental groups, approx. 15.2% and 14.4% on a fresh matter basis and 11.7% and 10.9% on a dry matter basis more methane and biogas were generated compared to the control group, respectively. Therefore, it can be assumed that the use of CA in cow nutrition improved dietary digestibility, which increased the efficiency of the use of feces organic matter for biogas production.