Initial BW Research Articles

Standardized Ileal Digestibility of Amino Acids in Hybrid Rye Ground to Two Particle Sizes and Fed With or Without Multienzyme Supplement to Young Growing Pigs.

A newly developed hybrid rye with enhanced ergot resistance has potential as an alternative energy source for pigs. An experiment was conducted to evaluate the effects of particle size (PS) and multienzyme supplement (MES) on the apparent total tract digestibility (ATTD) of energy and nutrients and the standardized ileal digestibility (SID) of amino acids (AA) in hybrid rye fed to growing pigs. Bono and Gatano, two hybrid rye varieties, were ground to either a coarse (1111 and 1210 μm) or a fine (594 and 717 μm) PS using a hammer mill. Eighteen ileal-cannulated barrows (initial BW = 18.2 ± 1.0 kg) were randomly assigned to 1 of 9 dietary treatments in a replicated 9 × 3 incomplete Latin square design to give six observations per treatment. Among the nine experimental diets, eight featured two hybrid rye varieties (Bono or Gatano), either coarsely or finely ground, as the only source of AA with or without MES, while an N-free diet was used to estimate the endogenous losses of AA at the distal ileum. All diets contained titanium dioxide as an indigestible marker. Each period lasted 9 days, with the first 5 days being for adaptation followed by 2 days each for faecal and ileal digesta collection. Data were analysed using the MIXED procedure of SAS, with the final model having variety, PS, MES, their two-way interactions, and a three-way interaction. No interactions were noted except that the apparent ileal digestibility and SID of crude protein (CP) and most AA in Gatano had greater effects of MES than Bono (Variety × MES; p < 0.05). The ATTD of dry matter (DM), gross energy (GE) and CP were greater (p < 0.05) in Bono diets than in Gatano diets. Finely ground hybrid rye diets had higher (p < 0.05) ATTD of neutral detergent fibre assayed with a heat stable amylase and expressed inclusive of residual ash (NDF) and ether extract compared to coarsely ground hybrid rye diets. Dietary MES supplementation increased (p < 0.05) the ATTD of DM, GE, CP, NDF, acid detergent fibre expressed inclusive of residual ash, and ash in hybrid rye diets. In conclusion, the nutrients digestibility of hybrid rye can be affected by its variety. PS reduction improved the nutrient digestibility in hybrid rye, and MES supplementation improved the energy and AA digestibility in hybrid rye fed to growing pigs.

The Effects of Concentrate Supplement Levels on Feed Utilization and Red Meat Production of Blackhead Somali Sheep Fed Natural Pasture Grass Hay as a Basal Diet.

In recent years, consumers have become aware of their health, and their preference has been rapidly changing to consume less fatty meat. Therefore, devising a strategy to produce lean meat is a concern in this study. One of the strategies, among others, for lean meat production is controlling the amount of supplements given to sheep. Hence, muscle (lean) and adipose tissue (fat) require different amounts of energy to lie down. This study was conducted to evaluate the effects of concentrate supplementation levels on feed utilization and red meat production in Blackhead Somali sheep (BHS) fed natural pasture grass hay as a basal diet. A total of 16 BHS sheep weighing 19.5±0.2kg (mean±SE) at the beginning of the experiment were kept for 90 days by feeding two levels (1% [T1] and 1.75% [T2] body weight [BW] of sheep) of supplement. The sheep were blocked according to their initial BW (IBW), and the supplements were randomly assigned within a block. At the end of the feeding period, all sheep were slaughtered, and carcass and non-carcass data were recorded. Data were analysed using the SAS software version 9.1 of PROC GLM programme. Sheep fed T1 and T2 consumed 6.1 and 8.2MJ/day metabolizable energy (ME), respectively, and 73.1 and 93.6g/day crude protein (CP), in that order. Consequently, sheep fed T2 produced 1.37kg extra BW by growing an average rate of 15g/day greater (p<0.0001) over their counterpart fed T1. They also produced 0.9kg, 0.8 cm2 and 2.64% heavier carcasses, a wider rib eye area and a higher intramuscular fat content (p<0.0001), respectively, over the sheep fed T1. On the other hand, the lean-to-fat ratio was significantly lower in sheep fed T2 than T1. In most parameters considered in this study, sheep fed T2 (1.75% BW) were superior, but its intramuscular fat (IMF) content was much higher than the limit that the consumers needed. Therefore, it can be concluded that 1% BW supplementation is enough for BHS to produce lean meat containing the optimal fat content in stall feeding condition.

PSVI-22 Effects of supplementation of beef cows during gestation on progeny backgrounding frame size and performance

Abstract The implications of supplementation during gestation on growth and efficiency of offspring have gained interest worldwide. The hypothesis of this study was that supplementation of cows during gestation results in favorable progeny growth and nutrient utilization. Our objectives were to assess the impacts of providing supplementation to pregnant beef cows during the dry grazing period on progeny backgrounding performance. During a 2-yr period, Tabapuã cows (n = 36) were managed on Brachiaria pastures, which were assigned to 1 of 3 treatments as follows: no application of N on pasture and cows supplemented with mineral mix (CON), application of 165 kg of Nּ ha-1ּ yr-1 and cows supplemented with a commercial product containing 40% of CP, macro and micro minerals, and vitamins (SUP), and application of 165 kg of Nּ ha-1ּ yr-1 and cows supplemented with grass silage (GS). At the beginning of the dry period, the commercial supplement and silage were fed for 140 d (from 116 ± 27 to 256 ± 27 d of gestation). The mineral mix was offered all year round. Bull (n = 18 in yr 1 and 12 in yr 2) and heifer progeny (n = 13 in yr 1 and 17 in yr 2) were weaned with average age of 203 ± 18 d in yr 1 and 229 ± 15 d in yr 2. After weaning, progeny were weighed and allocated in individual pens and adapted to a growing diet over 90 in yr 1 and 89 d in yr 2. For both years, rations were formulated to provide 0.9 kg/d (Dietary NEm = 1.68 Mcal/kg and dietary Neg = 1.07 Mcal/kg, on average). The PROC MIXED procedure of SAS was used to analyze all variables. The statistical model included supplementation program as a fixed effect and sex (male or female) as a random variable. Initial BW, weaning age, estimated progeny difference, and d on feed were included as covariates. No differences were obtained for initial BW, final BW, ADG, DM intake, and G:F. Frame size (e.g., heart girth, hip height) was also unaffected by dam supplementation. Overall, supplementing pregnant beef cows, during the dry grazing period, with a commercial supplement or silage does not affect progeny performance during backgrounding.

PSLBI-13 Characterizing the seminal microbiota in mature rams managed on divergent planes of nutrition, and in their male offspring

Abstract Increasing evidence suggests that the bovine semen harbors commensal microbiota, and it may be important in male fertility. However, much is unknown regarding the seminal microbiota, its evolution and factors shaping this community in sheep. The objective of this study was to evaluate whether managing the rams on divergent planes of nutrition can influence the seminal microbiota in mature rams and their male offspring. For this, Rambouillet rams (n = 24; 1.5 to 4 yr old) were randomly assigned to one of three groups: 1) a positive plane of nutrition [target 12% gain in their initial body weight (BW; POS, n = 8); 2) a maintenance [maintain the initial BW (MNT, n = 8)]; and 3) a negative [target a 12% reduction in BW (NEG; n = 8)] plane of nutrition over 84 d. The rams were individually housed and fed a common diet, and feed allocations were adjusted weekly. Following the 84-d feeding period, these rams were used to breed 240 mature Rambouillet ewes (1:10 ram:ewe ratio) over 28 d of breeding. After lambing, the male lambs were maintained on a similar diet for 124 d. Semen samples from the mature rams (F0 generation) were collected on d 28, 56, and 84, and semen samples from offspring rams (F1 generation) were collected at 330 d of age via electroejaculation. Genomic DNA was extracted from semen samples and the seminal microbiota characterized using 16S rRNA gene (V3-V4) sequencing. Several environmental and negative extraction controls were also sequenced to assess potential contaminants in these samples. Overall community structure of the seminal microbiota in F0 rams was not affected by the divergent planes of nutrition (PERMANOVA: P ≥ 0.05) or by sampling time (P &amp;gt; 0.05). Microbial richness (observed ASVs) was also not different (P &amp;gt; 0.05) between the three groups of F0 rams at any of the sampling time points; however, microbial diversity (P &amp;lt; 0.05) in the F0 rams was influenced by sire dietary treatment. Microbial community structure, richness and diversity did not differ among the POS, MNT and NEG F1 generation rams (P &amp;gt; 0.05). Actinobacteriota, Firmicutes, Bacteroidota, Proteobacteria and Fusobacteriota were the most abundant phyla. Only Bacteroidota abundance was significantly (P &amp;lt; 0.05) different between three F0 groups, with POS rams had greater (18.6%) of this phylum on d 28 as compared with MNT (2.1%) and NEG (5.1%). The predominant genera identified included Fastidiosipila, Corynebacterium, Trueperella, Arthrobacter, Dietzia, Bifidobacterium, Streptobacillus, Ornithinimicrobium, and Porphyromonas, and their relative abundance was not affected (P &amp;gt; 0.05) by the dietary treatment in F0 rams. Overall, rams managed on positive and negative planes of nutrition harbored similar seminal microbiota to control rams, and divergent nutrition also had no effect on the offspring ram seminal microbiota.

353 Zinc supplementation prior to transit and transit duration effects on feedlot performance and muscle fatigue of beef steers: Part I – Performance and Muscle Fatigue

Abstract This study investigated zinc (Zn) as a mitigation strategy for transit-induced muscle fatigue. Recently weaned Angus-cross steers (n = 80) were stratified by body weight (BW = 265 ± 18.0 kg) to a 2×2 factorial. Dietary (DIET) treatments of no supplemental Zn (Zn0) or 100 mg supplemental Zn/kg DM (Zn100; Zn as ZnSO4), were fed for 42 d before transit. Along with a transit duration (DUR) of 8 h (~707 km; 8H) or 18 h (~1,608 km; 18H) on d 0. Upon return, and for 56 d post-transit, all steers received Zn100. Individual feed disappearance was monitored using GrowSafe bunks (1 bunk/pen; 5 steers/pen). Body weights were collected on d -42, -41, -1, 0 (on truck), 1 (off truck), 2, 7, 28, 55, and 56. Blood samples for analysis of non-esterified fatty acid (NEFA) and serum L-lactate were collected on d -1, 1, 2, and 7. Data were analyzed via ProcMixed of SAS (experimental unit = steer; 15 to 20/treatment) as a 2 × 2 factorial, with fixed effects of DIET, DUR, and the interaction. Individual initial (d -42) BW was used as a covariate in BW analysis. Average DMI of d -11 to d -2 (pre-trucking) was used as a covariate in post-transit DMI analysis. Blood parameters were log-transformed and analyzed as repeated measures with repeated effect of day. Pre-transit (d -1) concentrations were used as a covariate. Pre-transit average daily gain (ADG) and dry matter intake (DMI) were greater (P ≤ 0.02) and feed efficiency (gain to feed; G:F) tended to be greater (P = 0.10) in Zn100 vs. Zn0. BW on d -1 and 7 (P = 0.01) was greater for Zn100 than Zn0. There was a DIET effect and DUR tendency on post-transit G:F where Zn0 was greater than Zn100 (P ≤ 0.01) and 18H tended to be greater than 8H (P = 0.05). 56-d post-transit ADG was least for Zn100-8H (DIET×DUR, P = 0.02). Post-transit DMI was greatest for Zn0-8H with Zn100-8H being the lowest and other treatments being not different (DIET × DUR, P = 0.04). Diet did not affect L- lactate or NEFA concentrations (P &amp;gt; 0.13). NEFA was greater for 18H vs. 8H on d 1 and 2 but less on d 7 (DUR×DAY, P &amp;lt; 0.01). There was a DUR×DAY effect (P ≤ 0.01) for L-Lactate where 8H tended to be greater than 18H on d 1, but by d 2 8H was lesser than 18H, and on d 7 they were not different. In conclusion, longer transit duration increases some indicators of muscle fatigue and Zn supplementation improved pre-transit performance. Receiving Zn supplementation after trucking also improved the post-transit performance of those not previously supplemented with Zn.

Effects of a Bacillus-based direct-fed microbial on performance, blood parameters, fecal characteristics, rumen morphometrics, and intestinal gene expression in finishing beef bulls.

We evaluated the effects of supplementing direct-fed microbials (DFM), containing Bacillus licheniformis and Bacillus subtilis, on performance, rumen morphometrics, intestinal gene expression, and blood and fecal parameters in finishing bulls. Nellore × Angus bulls (n = 144; initial BW = 401 ± 45.5kg) were distributed at random in 36 pens (4 bulls/pen and 18 pens/treatment), following a completely randomized design. A ground corn-based finishing diet was offered for ad libitum intake twice a day for 84 d, containing the following treatments: 1) control (without DFM); 2) DFM (B. licheniformis and B. subtilis) at 6.4 × 109 CFU (2g) per animal. The data were analyzed using the MIXED procedure of SAS, with a pen representing an experimental unit, the fixed effect of the treatment, and the random effect of pen nested within the treatment. For fecal parameters (two collections made), the collection effect and its interaction with the treatment were included in the model. Bulls that received the DFM had a decreased dry matter intake (P ≤ 0.01), did not differ in average daily gain (2.05kg; P = 0.39), and had a 6% improvement in gain:feed (P = 0.05). The other performance variables, final BW, hot carcass weight, and hot carcass yield, did not differ (P > 0.10). Plasma urea-N concentration decreased by 6.2% (P = 0.02) in the bulls that received DFM. Glucose, haptoglobin, and lipopolysaccharides were not different between treatments (P > 0.10). Ruminal morphometrics were not affected by the treatment (P > 0.10). The use of DFM tended to reduce fecal starch (P = 0.10). At slaughter, bulls fed DFM had an increased duodenal gene expression of tryptophan hydroxylase-1 (P = 0.02) and of superoxide dismutase-1 (P = 0.03). Overall, supplementation with DFM based on B. licheniformis and B. subtilis to Nellore × Angus bulls in the finishing phase decreased dry matter intake, did not influence ADG, improved gain:feed, and increased the expression of genes important for duodenal function.

Changes in the Fatty Acid Composition of Vegetable Oils Affect the Feeding Behavior, Feed Preference, and Thermoregulatory Responses of Sheep

This research evaluated the effects of energy supplementation on sheep’s feeding behavior, feed preference, and thermoregulatory responses using technical cashew nutshell liquid (CNSL) and different vegetable oils with different unsaturated fatty acid (UFA) compositions. The experiment was completely randomized with five treatments: a mixture of CNSL (0.5%) + vegetable oils [canola (high in monounsaturated fatty acids—MUFA), and corn, soybean, sunflower, or cottonseed oil (high in polyunsaturated fatty acids-PUFA) at 1.5%] based on total diet dry matter, with eight replications. Forty uncastrated male sheep, with an average initial BW of 24.44 ± 1.5 kg, were evaluated for 70 days. The CNSL + vegetable oil blend did not affect DM and neutral detergent fiber (aNDF) intake (p &gt; 0.05). However, diets with canola oil resulted in higher SFA intake (p &lt; 0.05) than other oils. The canola oil + CNSL blend led to a higher intake of UFA and MUFA and lower PUFA intake than other oil blends (p &lt; 0.05). Sheep fed canola oil ruminated fewer boli per day than those fed soybean and sunflower oils. Using three sieves (pef1.18) reflected in higher sheep aNDF intake. Respiratory frequency and surface temperature of sheep were lower before feeding than 3 h after, without effects of the type of oil. Higher serum creatinine and cholesterol levels were observed in sheep fed CNSL with corn and canola oils compared to other oils. Serum calcium was lower in sheep fed CNSL with soybean and canola compared to sunflower and corn. Including CNSL with vegetable oils with different FA compositions did not affect physiological and thermographic variables. However, sheep showed better diet selectivity and lower bolus rumination with higher MUFA (canola oil) content. Including CNSL with canola oil in sheep diets is recommended, as it increases dietary energy content, enhances diet selectivity, reduces PUFA intake, and does not impact animal health.

Enteric methane emissions from zebu cattle are influenced by seasonal variations in rangeland fodder quality and intake

Rangeland fodder resources used to feed ruminants in the Sahel decline considerably in both quantity and quality from the wet to dry seasons. While it is widely assumed worldwide that this seasonality of fodder supply impacts intake levels and therefore enteric methane (eCH4) emissions, there are very few references based on in vivo measurements of eCH4 in this region. The purpose of this study was to test the assumption that the seasonality of fodder supply impacts intake levels and consequently eCH4 in ruminants. Thus, eCH4 was measured in vivo in Sudanese Fulani zebu cattle during three main seasons of the year (wet season: WS, cold dry season: CDS, and hot dry season: HDS). The experiment was carried out on 10 steers aged 32 months with an average (± SD) initial BW of 138 ± 5.8 kg (i.e. 0.55 Tropical Livestock Unit − TLU) and kept in individual pens. Animals were fed with natural rangeland fodder harvested each season following herders’ practices, i.e. green fodder in the WS and dry fodder hay in the CDS and HDS. Different levels of fodder were offered to the animals to reproduce the gradient of fodder availability on rangelands over the year (six trials): 3.3% BW during the CDS; 3.3, 2.3, and 1.4% BW successively during the HDS; and 2.3% in two sequential studies in the WS. Each trial lasted 3 weeks, split into 2 weeks of fodder adaptation and 1 week of data collection. The BW, quantity of voluntary DM intake, digestibility of DM digestibility and of OM digestibility, and eCH4 (GreenFeed® system) were measured for each animal. Fodder composition varied considerably between seasons (P < 0.05). The DM intake (g/kg BW per day) varied from 23.9 in CDS to 15.7 in HDS and 22.3 in WS (P < 0.001). The DM digestibility varied from 0.50 in CDS to 0.46 in HDS and 0.57 in WS. The eCH4 yields (g/kg DM intake per day) varied significantly from 25.2 in the CDS to 31.8 in the HDS and 20.5 in the WS. When extrapolated over a full year and irrespective of season, eCH4 emissions for steers amounted to 68.1 g/d (24.6 g/kg DM intake per day, 46.7 ± 3.34 kg of eCH4/TLU per year). Variations in the various parameters recorded in different areas and during the main seasons must therefore be accounted for in national inventories to refine eCH4 data for ruminants in Sub-Saharan Africa.

Heat-Killed Lactobacillus acidophilus Promotes Growth by Modulating the Gut Microbiota Composition and Fecal Metabolites of Piglets.

Probiotics can improve animal growth performance and intestinal health. However, understanding the effects of paraprobiotics on the growth performance and gut microbiota of piglets and how the paraprobiotics exert their impact are still limited. The present study was conducted to investigate the effects of heat-killed Lactobacillus acidophilus IFFI 6005 supplementation on the growth performance, intestinal microbiota, and fecal metabolites of piglets. First, a feed-additive sample of heat-killed Lactobacillus acidophilus IFFI 6005 was prepared by culture. Second, 96 (initial BW = 14.38 ± 0.67 kg, weaning age of 40 days) healthy piglets were selected and randomized into four treatment groups. Each treatment group consisted of three replicates (n = 8). Pigs were fed a basal diet (NC), basal diet plus antibiotics (PC), basal diet plus Lactobacillus acidophilus IFFI 6005 at 600 g/t (LA, 1.0 × 1010 cfu/g), and basal diet plus heat-killed Lactobacillus acidophilus IFFI 6005 at 600 g/t (HKLA), respectively; the trial lasted for 30 days. The results showed that the ratios of feed to gain (F:G) and diarrhea rate of both the HKLA and PC groups were significantly lower compared with the NC and LA groups (p < 0.05); however, there was no significant difference between the HKLA and PC group (p > 0.05). In addition, the average daily weight gain (ADG) of the HKLA group was significantly higher (p < 0.05) than that of the other three groups in terms of growth performance. Finally, 16S rRNA sequencing and metabolome analysis based on fecal samples further elaborated that the addition of heat-killed Lactobacillus acidophilus IFFI 6005 to the feed improved the intestinal microbial diversity and abundance (p < 0.05) and reduced the abundance of pathogenic bacteria (p < 0.05), but it did not affect the abundance of Lactobacillus (p > 0.05). Through the comparison of microbial abundance and metabolite content between the two groups (NC_vs_HKLA), the largest differences were found in six microorganisms and 10 metabolites in the intestine (p < 0.05). These differential metabolites were involved in the digestion, absorption and utilization of protein and starch, as well as in oxidative stress. In summary, addition of heat-killed Lactobacillus acidophilus IFFI 6005 as a new feed additive in piglets has beneficial effects on the growth performance, intestinal bacteria and metabolites, and can be used as an alternative to antibiotics.

Milk replacer galacto-oligosaccharide (GOS) inclusion rates for neonatal calves.

Galacto-oligosaccharide (GOS) is a prebiotic isolated from whey. This study evaluated the optimal inclusion rate for improving growth and health performance of neonatal calves. Eighty-eight 2-5-d old Holstein bull calves were blocked by initial BW and randomly allocated to 1 of 4 treatments using a RCBD. Treatments comprised a 22:20 (CP: fat) amino acid balanced milk replacer (MR) with GOS added at the rate of 0 g/d (Control or GOS0), 2 g/d (GOS2), 4 g/d (GOS4), and 8 g/d (GOS8). Calves received 0.283 kg MR in 1.9 L fed 2 x/d for the first 14 d, then increased to 0.42 kg in 2.84 L fed 2x/d through d 35, followed by 0.42 kg MR in 2.84 L fed 1x/d through d 42, followed by weaning. The GOS inclusion rate remained constant as milk volume increased. Calves fed GOS at 2, 4, and 8 g/d demonstrated similar growth performance compared with calves fed GOS0. Calves fed GOS4 demonstrated a carryover effect into post-weaning resulting in a tendency for increased (P < 0.08) BW (82.5, 83.0, 85.3, and 83.1 kg for GOS0, GOS2, GOS4, and GOS8, respectively), BW gains (37.8, 38.2, 41.3 and 38.6 kg), and ADG (687, 696, 751, and 701 g/d). The ADG was increased by 9.3% when feeding calves GOS4 compared with calves fed GOS0. Calf starter DMI was greater at 7 (1.73,1.86, 1.95, and 1.83 kg/d) and 8 (2.34, 2.50, 2.60, 2.49 kg/d) wk of age for calves fed GOS4 compared with calves fed GOS0 with remaining treatments being intermediate and similar. Feed conversion (0.552, 0.529, 0.563, 0.545 kg/kg) was greater for calves fed GOS0 and GOS4 g/d compared with calves fed GOS2 with calves fed GOS8 being intermediate and similar. Body frame gains were similar for calves fed all GOS inclusion rates. A treatment by week interaction at wk 2 indicated that calves fed GOS2 demonstrated greater fecal score = 0 d than calves fed the remaining treatments, indicating less scours. In conclusion, supplementing GOS to a milk replacer at 4 g/d fed to neonatal calves improved growth performance without compromising health conditions.

Impact of Partial Oil Removal on Energy Content of Distillers Grains Plus Solubles for Finishing Cattle.

Two experiments evaluated the impact of the reduction in the percentage of corn oil remaining in distillers grains plus solubles (DGS) after the ethanol plant de-oiling process or by adding corn oil back to DGS following de-oiling on finishing cattle performance and nutrient digestion. Experiment 1 utilized 320 yearling steers (initial BW = 413 kg; SD = 25 kg) fed in 32 pens (10 steers/pen) and assigned to one of four treatments (n = 8 pens/treatment). The four treatments consisted of a blended DRC:HMC corn control diet (CON), de-oiled modified distillers grains plus solubles included at 40% of diet DM (DODGS), de-oiled modified distillers grains plus solubles included at 38% of diet DM plus 2% added corn oil (DODGS + Oil), and full-fat modified distillers grains plus solubles included at 40% of diet DM (FFDGS). The DODGS product contained 8.9% fat while the FFDGS product contained 11.6% fat. Dry matter intake (DMI) was impacted by treatment (p = 0.01) with steers fed DODGS having the greatest DMI and steers fed CON, DODGS + Oil, and FFDGS having lower DMI. Dietary treatment tended to impact ADG (p = 0.06) with steers fed DODGS and DODGS + Oil having greater gains than CON, with FFDGS being an intermediate. As a result of increased ADG, G:F differed between treatments (p < 0.01) with the greatest feed efficiency observed for steers fed DODGS + Oil and FFDGS. Including MDGS in the diet improved G:F by 6 to 11% compared to feeding DRC:HMC corn blend, with an improvement in G:F of 4.9 and 1.2% for DODGS + Oil and FFDGS, respectively, compared to DODGS. Hot carcass weight was impacted by dietary treatment (HCW; p = 0.05), with DODGS- and DODGS + Oil-fed steers having the heaviest HCW, CON steers having the lightest HCW, and FFDGS being an intermediate. Experiment 2 was a 5 × 4 unbalanced Latin rectangle digestion experiment with four diets, five ruminally cannulated steers, and five periods that utilized the same treatments as Exp. 1. Dietary fat measured 4.2, 6.0, 7.9, and 7.1% for CON, DODGS, DODGS + Oil, and FFDGS, respectively. Intakes of DM, OM, and energy as well as total tract fat digestibility and DE (Mcal/d) were not impacted by dietary treatment (p ≥ 0.46). When corn oil was added back to de-oiled MDGS, there was a negative impact on digestibility of OM (p < 0.01) and NDF (p = 0.07) compared with DODGS, FFDGS, and CON. Partially removing oil from modified distillers grains plus solubles did not significantly impact cattle performance, carcass traits, energy content, or digestibility when MDGS was included at approximately 40% of diet DM.

Body weight, scrotal parameters and semen characteristic of Kano Brown Buck Kids fed Pluerotus ostreatus solid state fermented sugarcane scrapings

The study evaluated the effect of substitution of Pleurotus ostreatus biodegraded sugarcane scrapings (BSS) for corn bran on the growth performance and reproductive potential of Kano Brown bucks. Twenty-one healthy buck kids (6 – 7 months of age, with an average initial BW of 9.44 ± 0.39 kg) were stratified into three treatments and fed: (1) a total mixed diet containing no BSS (0% BSS; control), (2) the control diet containing 15% BSS substituting 50% corn bran and (3) the control diet containing 30% BSS substituting 100% corn bran on dry matter basis (DM) for 12 weeks in a completely and fully randomized design. Intakes of DM, crude protein and organic matter, and sperm concentration varied in the order: 15% BSS &amp;gt; 0% BSS &amp;gt;30% BSS (p&amp;lt;0.05). Final BW, semen volume, initial fructose, scrotal length (SL) and scrotal circumference (SC) were greater in 15% BSS diet than 0 and 30% BSS diets. Semen pH and color, sperm progressive motility, viability and abnormalities, and live spermatozoa were not affected by diets. Whereas testosterone level was greater in 0 and 15% BSS diets, libido was lower in 30% BSS diet. Final BW was positively correlated with SC (p=0.030; r = 0.510) and SL (p = 0.048; r = 0.472). It was concluded that up to 30% biodegraded sugarcane scrapings can be used in a complete diet for bucks without negatively impacting final body weight and semen quality, though 15% BSS was more impactful and recommended.

Seminal Morphology and Organ Morphometrics of Rabbit Bucks Fed Piliostigma thonningii Essential Oil Supplemented Diet

This study aimed to investigate whether the inclusive supplementation of Piliostigma thonningii essential oil in rabbit diet was beneficial to their seminal morphometrics. Forty-five clinically healthy weaned male Dutch rabbits of about five weeks of age were used for the experiment. The rabbits were divided into three treatment groups, with fifteen rabbits per group and balanced for their body weight such that rabbits in each group had similar average initial BW of 0.27 kg. The experimental rabbits were administered P. thonningii essential oil at 0, 2 and 4 ml/kg for treatments T1, T2 and T3, respectively for 12 weeks. The results showed that left testis weight increased with increasing levels of P. thonningii essential oil supplementation. The normal cells, right testis weight and right and left testis volume were higher in T2 and T3 treatments than in T1. Right and left testis lengths were higher in T3 treatment than T1, with T2 being intermediate between T1 and T3. Mid-piece droplet, coiled tail, detached head, free tail, bent tail, right and left epididymis volume, head weight and length, body weight and length, weight and tail length and weight were not affected by treatments. It is concluded that P. thonningii essential oil supplementation improved some organ morphometrics without necessarily affecting sperm morphology in the experimental rabbit bucks.

Replacement Nellore heifers receiving supplementation under different herbage allowance: effects on forage characteristics, performance, physiology, and reproduction

In Brazil, heifers typically calve at 36–48 months. Due to the high demand for meat and the need to reduce slaughter age, high supplementation has become commonly used in beef cattle farming. However, the literature remains scarce on studies that explore the impact of grazing management during the background phase on the productivity and reproductive efficiency of young Nellore heifers. This study aimed to evaluate the effects of two-herbage allowances (HA) on forage characteristics, performance, physiology and reproductive parameters of replacement Nellore heifers. Ninety weaned heifers [169 ± 19 kg of shrunk body weight (SBW); 210 ± 28 days of age] were blocked by initial BW and randomly assigned to receive different HA: (1) High herbage allowance (HHA: 7.2 kg DM/kg BW) and (2) Low herbage allowance (LHA: 3.3 kg DM/kg BW); and divided into six paddocks, totaling 12 paddocks. The experimental period was divided into the growing phase (D173) and the reproductive season (D83). Continuous stocking with a variable stocking rate was used. The supplement was provided daily with expected intake of around 10 g/kg of BW. The HHA pasture showed greater values of canopy height, greater HA, and lower values of CP and CP: in vitro digestible DM ratio than the LHA pasture over the days of the study (P ≤ 0.05). Herbage mass and the green stem proportion were lower in LHA pasture (P < 0.01), while the green leaf (g/kg DM) and senescent stem proportions (g/kg DM) were higher (P = 0.080) when compared to HHA pasture. Heifers maintained on HHA pasture had a higher average daily gain (P < 0.01), forage intake (P < 0.003), higher SBW (P < 0.01), Longissimus area (P < 0.01), and 12th-rib fat thickness (P < 0.01) than those kept in the LHA pasture. The proportion of heifers that reached the weight at maturity on D173 (P = 0.027) and the proportion of pubertal pregnancy heifers (P = 0.042) were greatest in the HHA treatment. The blood urea nitrogen (P = 0.002) was higher in heifers maintained in the LHA pasture. Heifers maintained in HHA pasture showed higher values of relative abundance of mRNA for UGT1A6 (P = 0.004) and IGFBP3 (P = 0.072). The use of HHA criteria increased forage intake, body gain, and carcass attributes of animals, which led to better reproductive performance of Nellore heifers.

Effects of heat stress mitigation strategies on feedlot cattle performance, environmental, and economic outcomes in a hot climate

The increase in average global temperatures presents a challenge for the beef industry, especially in the feedlot sector where heat stress is a major animal welfare and economic concern. Shade is one of the most practical methods to mitigate heat stress in feedlot cattle. An experiment was conducted as a completely randomized design with 1 560 Bos indicus bulls (initial BW=287 kg) where three shade structure types were used to investigate the effects of different heat stress mitigation methods on cattle growth performance, environmental, and economic outcomes using live animal data, and a partial lifecycle assessment using the Integrated Farm System Model. The live animal portion of the experiment was done once a year over a 2-year period with three pen replications per treatment per year (n = 6 per treatment). Four shade structures used were conventional shade (SC; steel shade 1.8 m2 of shade/animal), double conventional shade (DS; steel shade 3.6 m2 of shade/animal), dome structures without fans (DSA; 8.5 m2/animal with 98% solar radiation blocked), and domes with fans (DCA; DSA plus three large sized low-speed fans). Each pen held 65 bulls in an area of 570 m2. Live animal data were analyzed as a completely randomized design using the GLM procedure of SAS (version 9.4) with shade type as fixed effect, pen as the experimental unit, and repetition (year) considered a random effect. Cattle housed under DCA had 22 and 20 kg heavier final body BW (P < 0.05) compared to those housed under SC and DS, respectively. Final BW of DCA and DSA cattle were similar (P > 0.05). Average daily gain, feed efficiency, and hot carcass weight were greater (P < 0.05) for cattle housed under DCA compared to the rest of the shade types. Dry matter intake was not affected (P > 0.05). When treatment results were extrapolated to the annual feedlot turnover of 209,700 animals, cattle in DSA and DCA versus SC and DS had 3–8% reductions in greenhouse gas and ammonia emission intensities. Compared to SC, DCA increased profitability by $29.66/animal, followed by DSA and DS with profit increases of $5.79 and $8.90/animal, respectively. Overall, the implementation of advanced shade structures improved cattle performance and profitability while reducing the environmental impact of beef production.

Effects of different concentrate levels in AGRI-002E sorghum silage-based diets on nutrient intake and digestibility, ruminal pH and ammonia concentration, ruminal degradability, and microbial efficiency in beef cattle

This study aimed to evaluate the effect of increasing concentrate levels in AGRI-002E sorghum silage (SS)-based diets on nutrient intake and digestibility, ruminal pH and ammonia concentration, Nitrogen (N) balance, efficiency of microbial protein synthesis, and in situ degradability of complete diets. Five rumen-cannulated Nellore bulls (age = 8 ± 1.0 months; initial BW = 242 ± 5 kg) received five dietary treatments in a 5×5 Latin square experimental design. The dietary treatments consisted of five concentrate levels (0, 200, 400, 600, and 800 g of concentrate/kg on a DM basis) in SS-based diets. The experiment lasted 120 d, with five periods of 24 d. Each period consisted of 17 d for dietary adaptation, and 7 d for data collection. In situ degradability assays were conducted to estimate ruminal degradability. Total feces and urine collection were performed to estimate nutrient intake and digestibility and estimate N balance. Omasal and ruminal digesta collection were performed to estimate ruminal digestibility and ruminal parameters. Increasing concentrate levels in SS-based diets led to linear increases (P<0.001) in the intake of dry matter (DM), organic matter (OM), crude protein (CP), and ether extract (EE). Neutral detergent fiber corrected for ash and protein contamination (apNDF) and starch intake showed quadratic responses (P≤0.008). Ruminal digestibility of DM, OM and CP responded quadratically (P≤0.040), while apNDF exhibited linear decrease (P=0.003). Starch ruminal digestibility exhibited a cubic effect (P=0.016). Apparent total-tract digestibility of DM, OM, and EE increased linearly (P≤0.001), whereas apNDF, and CP digestibility decreased linearly (P≤0.012), and starch presented a quadratic effect (P=0.029). In situ ruminal degradation parameters increased linearly with higher concentrate levels (P<0.001). Ruminal pH exhibited a quadratic pattern (P=0.006), ammonia concentration linearly decreased (P=0.003). Total volatile fatty acids, and butyrate showed linear increases (P<0.001), acetate and propionate had quadratic effects (P<0.001), while the ratio Acetate to Propionate decreased linearly (P<0.001). N intake, fecal N excretion, retained N, total digestible nutrients, digestible organic matter, and microbial production increased linearly (P<0.001), although urine N excretion, urinary urea, and blood urea concentration decreased linearly (P<0.028). Therefore, increasing concentrate levels in AGRI-002E sorghum silage-based diets improve TDN intake, microbial protein synthesis efficiency, in situ ruminal degradability parameters, and nitrogen utilization. Moreover, our findings indicate that AGRI-002E sorghum silage demonstrates potential as a fiber source for high-concentrate diets. However, its effectiveness is limited without concentrate supplementation, emphasizing the importance of balanced dietary composition for optimal utilization in beef cattle.

Effect of acidosis in the late-finishing phase on rumen fermentation in feedlot steers.

The objective was to determine the effects of induced acidosis in the late-finishing phase on rumen fermentation in feedlot steers. Eleven ruminally cannulated steers (body weight [BW] = 795 kg ± 54) were blocked into two groups based on initial BW. For 195 d prior to the start of the study, cattle were consuming a basal finishing diet (60% dry-rolled corn, 15% modified distillers grains, 15% corn silage, and 10% ground corn-based supplement). Steers were randomly assigned to one of the two treatments: control (CON), or induced acidosis (ACD). Both treatments were fasted for 24h then fed the basal finishing diet. Steers on the ACD treatment received 0.05% of BW of wheat starch via rumen cannula at 0800 and 2000 hours on day 1 and ad libitum refeeding following the fast. On days 1 and 2, CON steers were provided 25% of allotted feed every 6h. Rumen fluid was collected every 4h during the challenge period (hours 0 to 48), and 0, 6, and 12h after feeding during the recovery period (hours 54 to 96). Rumen fluid was analyzed for pH, ammonia, volatile fatty acids (VFA), and lactate. Fecal grab samples were collected every 8h to determine fecal pH. A treatment × day interaction (P = 0.03) was observed for dry matter intake during the challenge period with steers on the ACD treatments consuming more on day 1 than CON steers. Intake was not different on day 2 (P = 0.88). A treatment × hour effect (P < 0.01) was observed for ruminal pH during the challenge period with the ACD steers having a lesser pH than CON from hours 12 to 32. Duration of time below a pH of 5.6 during the challenge period was greater (P < 0.01) for ACD steers than CON. During the challenge period, a treatment × time interaction (P = 0.04) was observed for total VFA concentration with ACD steers having greater total VFA concentration from hours 12 to 36. Acetate to propionate ratio (A:P) was affected by treatment × hour (P = 0.04) with CON steers having greater A:P from hours 28 to 48. Rumen ammonia and lactate concentrations did not differ (P ≥ 0.25) between treatments or the interaction with time. Challenge and recovery period fecal pH were not affected (P ≥ 0.13) by treatment, time, or their interaction. Recovery period ruminal pH was not different (P = 0.99) between treatments. For the recovery period, total VFA and ammonia concentration were not affected by treatment, time, or their interaction (P ≥ 0.07). Ruminal pH and VFA were affected in the initial 48h of induced acidosis in the late-finishing phase.

Association of postabsorptive glucose and acetate metabolism with feed intake, growth, and efficiency in finishing beef heifers

The objective of this experiment was to determine whether acetate and glucose metabolism and insulin response to glucose are associated with the growth, feed intake, and feed efficiency of finishing heifers. Charolais heifers ( n = 18; initial body weight = 415.7 ± 45.17 kg) were acclimated to restraint with a halter and fed a finishing diet ad libitum using an Insentec feeding system. Following a 12 h fast, a jugular catheter was inserted, and an acetate clearance test was performed followed by a glucose clearance test. Four days after the metabolic tests, heifers began an 84-day DMI and ADG test period. Heifers gained 1.69 ± 0.03 kg/day and consumed 10.4 ± 0.19 kg/day. Acetate and glucose clearance rates were not associated with any production trait ( P ≥ 0.40). Insulin time to peak concentration after the glucose challenge was associated ( r = 0.69; P = 0.003) with G:F, but not peak concentration ( P = 0.45). The increased time to insulin peak could indicate that efficient heifers have pancreatic β-cell dysfunction, which is a contributor to insulin resistance. These data indicate that insulin resistance early in the finishing period could be related to improved feed efficiency in finishing heifers.

Dietary effects of protected fat, glycerol, and soybean meal on performance, physiological parameters, carcass characteristics, and behavioral measurements of late-fattening Hanwoo steers under heat stress conditions.

This study aimed to determine the effects of increasing energy and protein levels in diets by including protected fat (PF), glycerol (GL), and soybean meal (SBM) on growth performance, physiological parameters, carcass characteristics, and behavioral measurements of late-fattening Hanwoo steers under heat stress conditions. Thirty-six steers (initial body weight, 724.9±58.3 kg; age, 25.5±0.4 month) were assigned into control (total digestible nutrient [TDN] 76%, crude protein [CP] 15%), PF (TDN 83.6%, CP 15%), PF+GL (TDN 83.6%, CP 15%) and PF+GL+SBM (TDN 83.6%, CP 16.5%) by randomized complete block design for a total of 16 weeks with division of 4-week periods. The average temperature-humidity index was 87.0 (1st period; severe), 82.8 (2nd; moderate), 71.4 (3rd; comfort), and 68.1 (4th; comfort). The dry matter intake (DMI) showed no treatments differences during the whole experiment. However, DMI in 1st and 2nd period decreased by approximately 30% and 10% compared to 4th period, respectively. Higher average daily gain and feed conversion ratio were noted for treatments compared to control at both 1st and 2nd period (p<0.05). There were no treatment effects on rectal temperature (RT), cortisol, and behaviors during the entire experiment. However, both RT and cortisol in 0, 1st and 2nd period were higher than those of 3rd and 4th period (p<0.05). Carcass yield and grade remained unaffected by increasing TDN and CP levels. Behavioral changes in the hot season (1st period) included reduced lying (43%), increased standing (48%), decreased walking (62%), and decreased eating (38%) (p<0.05), with an increase in drinking by 54%. Rumination during standing was 53% higher, while rumination during lying was about 33% lower compared to the post-hot season (3rd period) (p<0.05). Dietary supplementation of protected fat in late-fattening Hanwoo steers under heat stress had a positive effect on preventing a reduction in performance.

Gut–brain bidirectional determination in regulating the residual feed intake of small-sized meat ducks

The gut-brain axis is essential in maintaining the homeostasis of neuronal system, endocrine system, and intestinal microbiota in both the afferent and efferent directions. This axis is considered to be a key mechanism that regulates feed efficiency (FE). This study aimed to investigate the regulatory mechanisms of gut-brain axis-related genes on the residual feed intake (RFI) in H-strain small-sized meat ducks. A total of 500 ducks with similar initial BW (635.2 ± 15.1 g) were selected and reared in the same experimental facility until slaughter at 42 d of age. RFI was calculated from the average daily gain (ADG), average daily feed intake (ADFI), and metabolic body weight (MBW0.75). Thirty high-RFI (H-RFI) and 30 low-RFI (L-RFI) birds were selected for further evaluation of growth performance, carcass characteristics, and blood biochemical parameter measurements. Six L-RFI and 6 H-RFI birds were then subjected to hypothalamic transcriptomic and cecal microbial sequencing analyses. Results indicated that L-RFI birds exhibited lower production performance (ADFI, FCR, and RFI) and blood biochemical indices (total cholesterol and ghrelin content) compared with H-RFI birds (P < 0.05). Gene expression differed significantly between the L-RFI and H-RFI birds, with 70 upregulated and 50 downregulated genes. The bacterial communities of L-RFI birds showed higher abundances of Bacteroides, Bifidobacterium, and Lactococcus, and lower abundances of Erysipelatoclostridium, Parasutterella, Fournierella, and Blautia compared with H-RFI birds (P < 0.05). Interactive analysis revealed bacterial communities associated with FE were significantly correlated with hypothalamic genes (P < 0.05), for example, Bacteroides was positively correlated with DGKH and LIPT2, while negatively correlated with CAPN9, GABRD, and PDE1A. Bifidobacterium showed significant correlations with ATP2A3, CALHM6, and TMEM121B. Overall, RFI was a crucial indicator of FE, regulated by interactions between brain gene expression and gut microbiota through cAMP signaling, neuroactive ligand-receptor interaction, and calcium signaling pathways. Notably, increased expression of hypothalamic genes and abundance of carbohydrate-utilization microbiota in L-RFI meat ducks improved FE by enhancing energy metabolism and volatile fatty acids absorption.