Dry Matter Intake Research Articles

Chromium and Palmitic Acid Supplementation Modulate Adipose Tissue Insulin Sensitivity in Postpartum Dairy Cows

Periparturient dairy cows exhibit intense lipolysis driven by reduced dry matter intake, enhanced energy needs, and the loss of adipose tissue (AT) insulin sensitivity. Extended periods of low insulin sensitivity and negative energy balance induce lipolysis dysregulation, leading to increased disease susceptibility and poor lactation performance. Chromium (Cr) supplementation improves systemic insulin sensitivity, while palmitic acid (PA) increases energy availability for milk production. However, the effect of supplementing Cr and PA alone or in combination on insulin sensitivity in AT is unknown. Thirty-two multiparous cows were used in a randomized complete block design experiment and randomly assigned to one of 4 diets fed from 1 to 24 DIM. Diets included: control, no supplementation (CON, n = 8); Cr (Cr-propionate at 0.45 ppm Cr/kg DM, n = 8); PA (1.5% DM, n = 8); or Cr+PA (n = 8). Plasma samples were collected at -13 ± 5.1 d prepartum (PreP), and 14.4 ± 1.9d (PP1) and 21 ± 1.9d (PP2) after calving for albumin, BHB, BUN, calcium, cholesterol, glucose, nonesterified fatty acids (NEFA), total protein, iron, transferrin, triglycerides, and oxylipids quantification. Subcutaneous AT (SCAT) explants were collected at PreP, PP1 and PP2 and incubated in the presence of the lipolytic agent isoproterenol (ISO = 1 µM, BASAL = 0 µM) for 3 h. The antilipolytic effect of insulin (1µL/L) on SCAT explants was evaluated during ISO stimulation (IN+ISO). Lipolysis was quantified by glycerol release in the media (nmol glycerol/mg AT). Macrophage infiltration and adipocyte size were measured using hematoxylin and eosin-stained AT sections and immunohistochemistry. Cr tended to reduce postpartum NEFA concentrations when compared with CON, PA, and Cr+PA. Likewise, Cr increased the percentage of large adipocytes (>9000 µm2) postpartum compared with other diets. In line with higher lipid content, Cr-fed cows had higher ex-vivo BASAL lipolysis at PP2 when compared with PA and Cr+PA. ISO induced higher lipolysis at PP1 and PP2 but it was not affected by Cr and PA. IN+ISO reduced lipolysis by 29.91 ± 11% in Cr compared with ISO. In contrast, IN+ISO did not affect ISO lipolysis in CON, PA, and Cr+PA. Plasma transferrin was reduced by Cr. At PP2, PA cows had 3.3-fold higher macrophage infiltration in SCAT when compared with CON and Cr. Plasma 9-HODE and 9-oxoODE were increased by Cr+PA. PA increased plasma 13-oxoODE and Cr increased the ratio of 13-HODE:13-oxoODE. PA increased 5-iso Prostaglandin F2α-VI. Our results demonstrate that supplementing Cr during the immediate postpartum enhances SCAT insulin sensitivity and lipid accumulation. Further studies should determine the effects and mechanisms of action of Cr and PA on AT lipogenesis, adipogenesis, and their impact on lactation performance.

Dietary macronutrient composition and partial soybean meal replacement with slow-release urea: Effects on performance, digestibility, rumen fermentation, and nitrogen metabolism in dairy cows

A 2 × 2 factorial arrangement of treatments was used to investigate the interactive effects of dietary macronutrient composition [high-starch, low-fat, low-fiber (HsLFF) than low-starch, high-fat, high-fiber (LsHFF)] and N source [soybean meal (SBM) or partially replaced by slow-release urea (SRU)] on lactation performance, rumen fermentation, N utilization efficiency, nutrient digestibility, blood metabolites, and feeding behavior in cows. A replicated 4 × 4 Latin square design was used involving 12 multiparous Holstein cows (milk yield of 40.5 ± 5.6 kg/d, BW of 590 ± 20 kg; 81 ± 12 d in milk). The HsLFF diet contained 300 g/kg starch, 31.3 g/kg fat, and 301 g/kg NDF, without straw or additional fat. In contrast, the LsHFF diet contained 195.5 g/kg starch, 60.8 g/kg fat, and 367.5 g/kg NDF, enriched with wheat straw (100 g/kg), and additional fat (34 g/kg). The diets were formulated to be iso-nitrogenous and isocaloric. Cows fed the HsLFF diet had greater DM intake, digestibility of DM and CP, milk yield and milk protein %, but lower intakes of NDF, and physically effective NDF, and milk fat % than cows fed the LsHFF diet. Replacing SBM with SRU significantly increased milk solids yield without affecting other lactation performance or BW. Cows fed the LsHFF diet had higher ruminal pH and branched-chain VFA proportions but lower total VFA concentrations compared with the HsLFF diet, while those on the LsHFF-SRU diet had the highest ruminal ammonia levels. Compared with the HsLFF diet, cows fed LsHFF had lower NE intake, milk energy output and energy requirement for maintenance, although energy balances were similar among groups. The HsLFF diet improved N utilization, resulting in higher N content in milk and lower N excretion in feces. Blood metabolite studies showed significant interactions between the main factors, particularly for blood glucose and creatinine, with the lowest levels in cows fed the LsHFF-SRU and LsHFF-SBM diets. In addition, alanine aminotransferase levels were higher in cows fed the LsHFF diet than in cows fed the HsLFF diet. This could indicate early-stage liver stress due to the metabolic imbalance caused by a high-fat, low-starch diet, which can alter energy metabolism. Cows on the HsLFF-SRU diet had the highest glucose levels, indicating possible changes in carbohydrate metabolism or a higher metabolic rate. The concentration of BUN increased steadily after feeding in the LsHFF diet and peaked after 4 h in the LsHFF-SRU diet, with no difference between N sources in the HsLFF diet. Partial replacement of SRU with SBM had no effect on BUN. The interaction between the main factors had a significant effect on MUN content, which was highest in LsHFF-SRU and lowest in HsLFF-SRU, with no difference between the N sources in the HsLFF diets. Overall, while diets with reduced starch and increased fiber and fat compromised lactation performance, partially substituting SRU with SBM helped maintain milk production and milk nitrogen efficiency. However, the LsHFF-SRU diet was less efficient in N utilization, as shown by higher levels of ruminal ammonia, BUN and MUN.

Effect of Replacing Corn Grain and Soybean Meal with Field Peas at Different Levels on Feed Intake, Milk Production, and Metabolism in Dairy Cows under a Restrictive Grazing.

This study assessed the effects of replacing soybean meal (SBM) and corn grain with field peas in the concentrate of grazing dairy cows on milk production, intake, ruminal fermentation, and blood indicators. Twelve multiparous lactating Holstein-Friesian cows were utilized in a replicated 3 × 3 Latin square design, comprising three periods and three treatments: (1) Pea-0 (Control diet): 6 kg dry matter (DM) of fresh pasture, 7.2 kg DM of grass silage, and 7 kg DM of a concentrate containing 0% pea; (2) Pea-30: Control diet with the concentrate composed of 30% pea; (3) Pea-60: Control diet with the concentrate composed of 60% pea. The effect of treatments on productive and metabolic parameters was evaluated using linear-mixed models. Pasture and total DM intake, milk production, and composition were unaffected by treatments. Despite the concentrates being isonitrogenous and isoenergetic, crude protein (CP) intake was slightly higher in Pea-30 and significantly higher in Pea-60 due to higher pasture CP content in the pasture grazed by these groups, leading to higher milk urea content, though within recommended ranges. Blood parameters showed no significant changes, except for plasma β-hydroxybutyrate, which was lowest in the Pea-60 treatment; however, all values were within ranges not indicative of subclinical ketosis. Ruminal fermentation parameters were similar across treatments. These findings support the use of field peas as a viable alternative to replace SBM and corn grain in concentrates, enabling similar milk production and composition in grazing dairy cows.

Impact of oil type and savory plant on nutrient digestibility and rumen fermentation, milk yield, and milk fatty acid profile in dairy cows

Fat supplements are well known for their multiple beneficial effects on ruminant health, reproduction and productivity, and as a source for certain bioactive compounds in ruminant products. On the other hand, numerous phytochemicals have demonstrated the potential to improve rumen fermentation through modifying the volatile fatty acid (VFA) pattern to favour those with greater energy efficiency, boosting microbial protein synthesis, and decreasing methane emission and ruminal ammonia concentration. Savory is an aromatic plant rich in various phytochemicals (mainly carvacrol and flavonoids) that can alter ruminal metabolism of dietary fatty acids, potentially increasing the production of some bioactive compounds such as conjugated linoleic acids (CLAs). This study aimed to investigate combined effects of oil type (fish oil (FO) versus soybean oil (SO)) and the inclusion of savory (Satureja khuzistanica) plant (SP) in the diet on total tract digestibility of nutrients, rumen fermentation, milk yield and milk fatty acid profile in dairy cattle. Eight multiparous lactating Holstein cows were used in a replicated 4 × 4 Latin square design experiment with four diets and four 21-d periods. During each experimental period consisted of 14 days of adaptation and a 7-day sampling period, cows were randomly assigned to one of the four dietary treatments: the diet supplemented with 2% (DM basis) fish oil (FOD) or soybean oil (SOD), the FOD or SOD plus 370 g DM/d/head SP (FODs, SODs, respectively). The experimental diets were arranged in a 2 × 2 factorial design, with the fat sources as the first and SP as the second factor. The FO-supplemented diets had lower dry matter intake (DMI) and higher total tract digestibility than SO-supplemented diets (P < 0.05), and including SP in the diet improved total tract digestibility of dry matter (DM), organic matter (OM), ether extract (EE), and non-fibrous carbohydrates (NFC) (P < 0.05) without negatively affecting DMI. Rumen pH was lower with SO than with FO diets (P < 0.01) and increased with SP inclusion in the diet (P < 0.05). Total protozoa count and ruminal ammonia concentration decreased, and the branched-chain VFA (BCVFA) proportion increased with SP inclusion in the diet (P < 0.05). Milk production, as well as the concentration and yield of milk components (except lactose concentration) were higher with SO than with FO diets (P < 0.05), but these variables remained unaffected by SP. The milk concentrations of both non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) were lower with SO compared to FO diets, and these variables were reduced by SP (P < 0.01). The proportions of both mono- and polyunsaturated FA (MUFA and PUFA, respectively) in milk were higher with FO than with SO diets (P < 0.01), and their proportions increased by SP at the expense of saturated FA (SFA) (P < 0.01). Including SP in the diet increased the proportions of all the milk n-3 FA (C18:3c, C20:5, and C22:6) by 21%, 40%, and 97%, respectively, and those of conjugated linoleic acids (C18:2 (c9,t11-CLA) and C18:2 (t10,c12-CLA)) by 23% and 62%, respectively. There was no interaction between oil type and SP for the assessed variables. Fish oil, despite reducing milk production and milk components, was more effective than soybean oil in enriching milk with healthy FA. These findings also show promise for SP as a feed additive with the potential to improve total tract digestibility, rumen fermentation and milk FA composition.

The composition of early lactation milk in recipient dairy cows determines success in bovine embryo transfer.

To identify new criteria for selecting recipient dairy cows for embryo transfer (ET), we retrospectively examined the effects of the composition of early lactation milk on fertility risk in ET. This study investigated the association between milk fat (FAT), milk protein (PRO), and milk urea nitrogen (MUN) levels during early lactation, based on production records, and subsequent fertility risk in ET using contingency table analysis and multivariable logistic regression analysis, which included five confounding variables. The results showed that MUN levels during early lactation were negatively associated with fertility risk in ET, while FAT and PRO levels showed no clear association. A reduction in MUN levels during the peak lactation period suggests a deficiency in dry matter intake, an inadequate protein supply, and an imbalance in the ratio of proteins to fermentable carbohydrates in the rumen, which may have adversely impacted fertility risk in ET.Monitoring MUN levels is crucial for maintaining a proper protein balance. The results obtained in this study suggest that MUN levels in the early lactation phase obtained from production records can be used as a predictor of fertility in recipients to improve the fertility risk in ET. No special techniques or costs are required for using production records, making them easy to use in clinical practice. Our findings provide valuable insights for optimizing cost-effectiveness and fertility risk in ET and their clinical applications.

Pre- and postpartum metabolizable protein supply: I. Effects on feed intake, lactation performance, and metabolic markers in transition dairy cows.

The objective of this study was to investigate the effect of increasing MP supply in the prepartum, postpartum, or both diets on intake, performance, and metabolic indicators. Multiparous Holstein cows (n = 96) were assigned to 1 of 4 treatment groups at 28 d before expected calving following a randomized block design. Prepartum diets were formulated to contain either a control (C; 85 g of MP/kg DM) or high (H; 113 g of MP/kg DM) level of estimated MP. From calving to 21 DIM, diets were formulated to contain either a control (C; 104 g of MP/kg DM) or high (H; 131 g of MP/kg DM) level of estimated MP. To control the potential confounding effect of Met and Lys supply, diets were formulated to supply an equal amount at 1.24 and 3.84 g/Mcal of ME in both prepartum diets and 1.15 and 3.16 g/Mcal of ME in both postpartum diets, respectively. The combination of a pre- and postpartum diet resulted in 4 treatment groups: 1) CC (n = 23), 2) CH (n = 24), 3) HC (n = 22), and 4) HH (n = 23). A common lactation diet (113 g of MP/kg DM) was fed from 22 DIM to the end of the observation period at 42 DIM. Milk yield and DMI were collected daily, and plasma metabolic indicators (BHB, fatty acids [NEFA], urea nitrogen [PUN], and glucose) were determined twice weekly from -28 to 28 d relative to calving and once weekly from 29 to 42 DIM. Samples with BHB ≥1.2 mmol/L between 3 and 10 DIM were considered hyperketonemia events. Milk composition was determined weekly. Milk yield during 1 to 21 DIM was greater in HH (44.7 ± 1.0 kg/d) compared with CC (39.2 ± 1.0 kg/d) and HC (38.0 ± 1.0 kg/d) and milk yield in CH (42.4 ± 0.9 kg/d) was greater than HC, respectively. From 22 to 42 DIM, milk yield was greater in CH (53.3 ± 1.0 kg/d) and HH (54.1 ± 1.0 kg/d) compared with CC (49.6 ± 1.0 kg/d) and HC (49.3 ± 1.0 kg/d). Dry matter intake (% of BW) and concentrations of milk protein, fat, and total solids were not affected by treatment. Prepartum concentrations of PUN were greater in H compared with C. From 1 to 21 DIM, PUN concentrations were greater in CH and HH compared with CC and HC. From 1 to 21 DIM, glucose concentrations were lower in HH compared with HC and BHB were greater in CH and HH compared with HC. Concentrations of NEFA, as well as the number of hyperketonemia events did not differ by treatment during this time. From 22 to 42 DIM, concentrations of NEFA were greater in HH compared with HC and concentrations of BHB were greater in CH and HH compared with HC. Overall, feeding CH or HH increased lactation performance without altering intake or hyperketonemia events. Results from this study support formulating a fresh diet to reduce the negative MP balance during early lactation.

Intestinal microbiota composition in broilers fed protein-free or casein-based diets

Growing broiler chickens of the Cobb500 strain were used to determine the effects on intestinal microbiota composition of a protein-free (PF) diet as compared to a diet based in casein (CAS) as the only protein source. CAS was formulated to contain the same amount of protein (190 g kg-1) as a commercial Maize-soy diet which was used as a practical reference. The ileal AA flow (g kg-1 dry matter intake) was significantly higher (P < 0.001) than PF in birds fed protein containing diets (CAS or Maize-soy). Taken as a whole (discriminant and ANOSIM analysis), the intestinal (ileal and caecal contents and ileal tissue) microbiota composition of PF and CAS were significantly (P < 0.001) different from Maize-soy and not different from each other in some cases. RT-qPCR and sequencing analysis of the ileal and caecal microbiota revealed significant (P < 0.05) differences in a number of bacterial groups between broilers fed PF, CAS or Maize-soy diets. The main result was that the lack of protein in the intestinal medium of PF birds resulted in a drop of Lactobacillus spp. counts (on average, 43 in PF vs 1,734 in the Maize-soy diet) and increased Enterobacteriaceae (on average, 419 in PF vs 172 in the Maize-soy diet) and other potentially pathogenic bacterial groups (in both intestinal contents and tissue). Thus, the lack of protein in the intestinal medium of PF birds resulted in a microbiota composition compatible with a pro-inflammatory state, and this effect was somewhat less marked in birds fed CAS. The results reported here suggest that the adverse effects on microbiota composition in broilers fed CAS were less marked than in those fed PF, which would be in line with a preferential use of a highly digestible protein containing diet to determine endogenous AA excretion instead of a PF diet.

Dried distiller’s grains in the diets of feedlot lambs: implications for production, carcass characteristics and rumen morphometrics

Context The demand and production of renewable fuels are boosting the production of biofuels. Agricultural industries have been playing a role in the increase of ethanol production from corn and, consequently, their by-products. Dried distiller’s grain (DDG) is a by-product of corn ethanol and can be used as a source of protein and energy in the diet of feedlot lambs. Aims The objectives of this experiment were to evaluate the effects of including DDG in high-concentrate diets on performance, rumen morpho-histology, and carcass characteristics in feedlot lambs. Methods Forty-five Santa Inês × Dorper male lambs with an initial body weight of 21 ± 3.2 kg (mean ± s.d.) and 82 ± 12 days old (mean ± s.d.) were distributed in a randomised complete-block design (nine blocks and five treatments). The experimental diets contained 900 g/kg of concentrate and 100 g/kg of coastcross hay, and DDG was used in replacement of soybean meal and corn. Lambs were fed one of the following five diets for 112 days: control without DDG (0DDG), or diet with 150 (150DDG), 300 (300DDG), 450 (450DDG) and 600 (600DDG) g/kg DM of DDG. Key results The inclusion of DDG from 150 up to 600 g/kg DM in the diet of the lambs linearly decreased (P &lt; 0.01) dry-matter intake (DMI), net energy of maintenance intake, net energy of gain, average daily gain, final body weight and feed efficiency (P &lt; 0.01). The inclusion of DDG linearly decreased (P ≤ 0.04) hot carcass weight, cold carcass weight, hot carcass yield and cold carcass yield. For ruminal morpho-histology, there was a linear decrease in the area of papillae and absorptive surface area (P &lt; 0.01) Conclusions An increase in the DDG level from 150 to 600 g/kg DM in the diet of lambs negatively affected feedlot performance, with detrimental effects on carcass traits and the development of rumen papillae. The lambs showed low acceptance of DDG, even at the lowest level of dietary inclusion (150g/kg DM) as DMI was impaired. Implications DDG should be used with caution in diets for finishing lambs. Dietary inclusion of DDG up to 150 g/kg DM is recommended. Higher inclusions levels may significantly affect performance and carcass weight and yield.

Hybridization promotes growth performance by altering rumen microbiota and metabolites in sheep.

Hybridization can substantially improve growth performance. This study used metagenomics and metabolome sequencing to examine whether the rumen microbiota and its metabolites contributed to this phenomenon. We selected 48 approximately 3 month-old male ♂Hu × ♀Hu (HH, n = 16), ♂Poll Dorset × ♀Hu (DH, n = 16), and ♂Southdown × ♀Hu (SH, n = 16) lambs having similar body weight. The sheep were fed individually under the same nutritional and management conditions for 95 days. After completion of the trial, seven sheep close to the average weight per group were slaughtered to collect rumen tissue and content samples to measure rumen epithelial parameters, fermentation patterns, microbiota, and metabolite profiles. The final body weight (FBW), average daily gain (ADG), and dry matter intake (DMI) values in the DH and SH groups were significantly higher and the feed-to-gain ratio (F/G) significantly lower than the value in the HH group; additionally, the papilla height in the DH group was higher than that in the HH group. Acetate, propionate, and total volatile fatty acid (VFA) concentrations in the DH group were higher than those in the HH group, whereas NH3-N concentration decreased in the DH and SH groups. Metagenomic analysis revealed that several Prevotella and Fibrobacter species were significantly more abundant in the DH group, contributing to an increased ability to degrade dietary cellulose and enrich their functions in enzymes involved in carbohydrate breakdown. Bacteroidaceae bacterium was higher in the SH group, indicating a greater ability to digest dietary fiber. Metabolomic analysis revealed that the concentrations of rumen metabolites (mainly lysophosphatidylethanolamines [LPEs]) were higher in the DH group, and microbiome-related metabolite analysis indicated that Treponema bryantii and Fibrobacter succinogenes were positively correlated with the LPEs. Moreover, we found methionine sulfoxide and N-methyl-4-aminobutyric acid were characteristic metabolites in the DH and SH groups, respectively, and are related to oxidative stress, indicating that the environmental adaptability of crossbred sheep needs to be further improved. These findings substantially deepen the general understanding of how hybridization promotes growth performance from the perspective of rumen microbiota, this is vital for the cultivation of new species and the formulation of precision nutrition strategies for sheep.

Methane emission, nitrogen excretion, and energy partitioning in Hanwoo steers fed a typical TMR diet supplemented with Pharbitis nil seeds.

Two in vivo experiments were conducted to evaluate the potential of Pharbitis nil seeds (PA) as an anti-methanogenic additive to ruminant feed. In experiment 1, six Hanwoo steers (459.0 ± 25.8 kg) were fed either a total mixed ration (TMR; 32-d period) or TMR supplemented with PA at 5% dry matter (DM) intake (TMR-PA; 45-d period) for two consecutive periods. Fecal and urine outputs were measured in an apparent digestibility trial in both periods. Methane (CH4) yield and heat energy (HE) were measured using respiratory chambers equipped with gas analyzers. In experiment 2, five rumen cannulated Holstein steers (744 ± 35 kg) were fed the same TMR or TMR-PA diets for 40 days; rumen samples were collected at 0, 1.5, and 3 h after feeding on the last day of the feeding period. In experiment 1, although there were no differences (p > 0.05) in nutrients or gross energy intake (GEI) between the groups, an increase (p < 0.05) in the apparent digestibility of DM (9.1%) and neutral detergent fiber (22.9%) was observed in the TMR-PA fed Hanwoo steers. Pronounced decreases (p < 0.05) in CH4 (g/Kg DM; 17.1%) and urinary N excretion (% N intake; 7.6%) were observed in the TMR-PA group, leading to a 14.7% increase in metabolizable energy intake (% GEI). However, only a numerical increase (p > 0.05) in retained energy was observed due to the increase in HE loss. In experiment 2, a drastic decrease (p < 0.05) in rumen ammonia concentration (56.3%) associated with an increased (p = 0.091) rumen short-chain fatty acid concentration 1.5 h after feeding were observed in TMR-PA fed Holstein steers. A 26.6% increase (p < 0.05) in the propionate proportion during the treatment period clearly reflected a shift in the ruminal H2 sink after 3 h of feeding. A 40% reduction (p = 0.067) in the relative abundance of rumen protozoa Entodinium caudatum was also observed. It was concluded that PA could be a natural feed additive for CH4 and N emission abatement.

Shifting feed delivery time: effects on feeding behavior, milk production, and blood biomarkers in late-lactating dairy cows

Improving the synchronization between the pattern of milk synthesis and nutrient availability throughout the day could enhance production efficiency. In this study, we evaluated the effects of changing feed delivery time on milk production, feeding behavior, and the daily rhythms of blood biomarkers. Eight multiparous Holstein cows housed in a tie-stall barn with controlled environmental conditions were enrolled in a crossover experimental design with three periods of 14 days and three treatments each. Cows were milked twice daily (0530 and 1730 h) and were individually fed with two equal meals of forage and eight equal meals of concentrate during the day. Forage meals were provided at 12-hour intervals either: (i) 5 h before each milking (0030 and 1230 h; BM), (ii) at the end of each milking (0530 and 1730 h; ME), (iii) or 2 h after (0730 and 1930 h; AM). Feed intake and feeding behavior were monitored, and milk production and composition were measured. Blood samples were collected every 4 days at 0700 h and, during the last day of each period, 15 times daily to determine metabolic profiles, hormones, and their daily rhythmicity by the cosinor analysis. Changing forage delivery time did not affect milk yield and dry matter intake. No difference was observed in feeding behavior when expressed relative to the first meal. There were no significant differences in milk component contents and yields. In samples collected at 0700 h, ME had reduced plasma calcium (Ca), magnesium (Mg), and potassium (K) and increased sodium (Na). AM had increased inflammation, as suggested by the greater blood globulin and ceruloplasmin. The patterns of metabolic biomarkers had limited variations when expressed relative to the first forage meal. Nevertheless, the daily rhythms of these biomarkers were remarkably different. Under our conditions, feeding forage meals to cows at different times of the day did not influence productive performance but highlighted the importance of considering the sampling time when interpreting metabolic profiles.

The Potential of Three Vetch Species in Enhancing Feed Intake and Body Weight Gain of Growing Male Lambs

An experiment was intended to evaluate the potential of three vetch species in enhancing feed intake and body weight gain of growing male lambs and to investigate the difference among these three vetch species regarding their effect of supplementation on feed utilization and growth performance of growing male lambs. Twenty-four young male Arsi-Bale lambs of similar body weight were assigned to one of the four treatments in a randomized complete block design. The dietary treatments were 350 g of hay each of &amp;lt;i&amp;gt;Vicia sativa,&amp;lt;/i&amp;gt; &amp;lt;i&amp;gt;Vicia Villosa,&amp;lt;/i&amp;gt; and &amp;lt;i&amp;gt;Vicia narbonensis&amp;lt;/i&amp;gt; for T2, T3, and T4, and ad libitum fodder oat hay alone (T1). Weight measurements of the lambs were made every ten days during the ninety-day feeding trial. Compared to T1 and T3, T2&amp;apos;s total dry matter intake (1121.4 g/day) was substantially (P&amp;lt;0.05) greater. Lambs fed T2 diets showed significantly higher (P&amp;lt;0.001) crude protein intake (153.3 g/day) and average daily body weight increase (152.0 g/day). In conclusion, supplementation with Vicia sativa (T2) resulted in the highest feed intake and growth performance of lambs across all treatments. As a result, efforts should be undertaken to introduce and expand the production of this forage within the farming system.

Performance Evaluation of Lambs Fed Tifton 85 Grass Hay and Concentrate Through LIPE® Marker

The research was carried out with the aim of evaluate increasing levels of concentrate supplementation on intake and performance of lambs fed Tifton 85 grass hay adopting LIPE® marker technique. Twenty-four weaned and castrated Santa Inês crossbreed lambs with initial body weight (BW) of 20.99 ± 3.62 kg were distributed in four treatments with Tifton 85 hay exclusive or associated with concentrate levels (0.0, 6.6, 13.3 and 20.0 g kg-1 BW d-1), in a completely randomized design with six animals per treatment. The experimental period lasted 98 days, with the first 14 days for animal adaptation to the new environmental conditions, handling and feeding. The diets were fed ad libitum twice a day. Lambs were weighted at each 14 days. Dry matter intake (DMI) was estimated by the technique of Isolated, Purified and Enriched Lignin (LIPE®) while neutral detergent fiber intake (NDFI) and crude protein intake (CPI) were obtained from the content of their fractions present in the diets. There was an increase in DMI and CPI and a similar response in NDFI with the increasing levels of concentrate. The daily liveweight gain per animal showed a linear response when the levels of concentrate were increased and the highest values wereobserved when 20.0 g kg-1 BW d-1 of concentrate was fed. The increasing levels of concentrate supplementation allowed greater daily and total body weight gains per lamb and there is a consistent relationship between nutrient intakes and performance in the treatments and the LIPE® marker proved to be an efficient technique to evaluate the DMI by lambs.

Relationship between the rumen microbiome and liver transcriptome in beef cattle divergent for feed efficiency

BackgroundFeed costs account for a high proportion of the variable cost of beef production, ultimately impacting overall profitability. Thus, improving feed efficiency of beef cattle, by way of determining the underlying genomic control and selecting for feed efficient cattle provides a method through which feed input costs may be reduced whilst also contributing to the environmental sustainability of beef production. The rumen microbiome dictates the feed degradation capacity and consequent nutrient supply in ruminants, thus potentially impacted by feed efficiency phenotype. Equally, liver tissue has been shown to be responsive to feed efficiency phenotype as well as dietary intake. However, although both the rumen microbiome and liver transcriptome have been shown to be impacted by host feed efficiency phenotype, knowledge of the interaction between the rumen microbiome and other peripheral tissues within the body, including the liver is lacking. Thus, the objective of this study was to compare two contrasting breed types (Charolais and Holstein-Friesian) divergent for residual feed intake (RFI) over contrasting dietary phases (zero-grazed grass and high-concentrate), based on gene co-expression network analysis of liver transcriptome data and microbe co-abundance network of rumen microbiome data. Traits including RFI, dry matter intake (DMI) and growth rate (ADG), as well as rumen concentrations of volatile fatty acids were also included within the network analysis.ResultsOverall, DMI had the greatest number of connections followed by RFI, with ADG displaying the fewest number of significant connections. Hepatic genes related to lipid metabolism were correlated to both RFI and DMI phenotypes, whilst genes related to immune response were correlated to DMI. Despite the known relationship between RFI and DMI, the same microbes were not directly connected to these phenotypes, the Succiniclasticum genus was however, negatively connected to both RFI and ADG. Additionally, a stepwise regression analysis revealed significant roles for both Succiniclasticum genus and Roseburia.faecis sp. in predicting RFI, DMI and ADG.ConclusionsResults from this study highlight the interactive relationships between rumen microbiome and hepatic transcriptome data of cattle divergent for RFI, whilst also increasing our understanding of the underlying biology of both DMI and ADG in beef cattle.

Nitrogen fertiliser application rate to temperate mid-season grass: Digestion, nitrogen balance and rumen microbiota in beef cattle, and rumen fermentation and methane production in vitro

Nitrogen (N) excretion by cattle, particularly urinary N, can have detrimental environmental impacts on air and water quality, and contributes to greenhouse gas emissions. The effects of increasing the application rate of inorganic N fertiliser from 15 (N15) to 80 (N80) kg/ha per cut to Lolium perenne dominant swards in summer, on intake, rumen fermentation, rumen microbial populations, apparent total-tract digestibility and N-balance in beef cattle, and in vitro fermentation and methane output, were studied. Sixteen suckler-bred Charolais steers, used in a randomised block design experiment, were offered fresh grass mechanically harvested 21-d after N fertiliser application. Similar grass was incubated in an eight-vessel in vitro RUSITEC system. Grass crude protein concentration was 50 g/kg dry matter (DM) higher for N80 compared to N15. There was no difference in grass DM intake between treatments. Rumen fermentation variables did not differ between treatments, except for the molar proportion of propionate, which was greater for N80 than N15. Gross microbial community structure in the rumen was not significantly altered by inorganic N fertiliser application rate. The relative abundance of individual genera Lachnospiraceae_NK3A320_group and Ruminococcaceae_NK4A214_group, and Acetitomaculum were significantly lower at the higher N application rate. Mean plasma urea concentration was greater for N80 compared to N15. In vivo digestibility of DM, organic matter, neutral detergent fibre and acid detergent fibre was unaffected by fertiliser N application rate. Nitrogen intake was 75 g/d greater, and urinary and faecal N excretion were 20 and 5 g/d greater, respectively, for N80 than N15. The quantity of N retained and N use efficiency was greater for N80 compared to N15. In vitro NH3 concentration was greater for N80 than N15, whereas other rumen fermentation variables, and in vitro methane and total gas output, did not differ between treatments. Reducing the inorganic N fertiliser rate applied to mid-season temperate grass reduced N excretion from beef cattle, which is environmentally beneficial, with no effect on in vitro methane production.

Performance evaluation of Uruguayan dairy farming systems

In the last 20 years, the Uruguayan dairy sector has intensified and concentrated on higher cow productivity, maintaining the herd, smaller land, and fewer farms. The research aims are to identify, describe, and evaluate the economic performance of different types of dairy farms. A sample of 284 farms from the National Dairy Farm Survey 2019 was used (representing 2,021 dairies); using k-means Cluster analysis with the variables: cow productivity, stocking rate, land productivity, concentrate, roughage, and grass intake (per hectare). We identified six farm types, three with high participation of grass in the cows’ diets (HG, 60% or more of dry matter intake), and the other three focused on supplementation (HS); with three intensification levels (1-low, 2-intermediate and 3-high productivity per ha). For the 2018/19 season three types of farms presented the best economic performance (HS-3, HG-3, and HG-2), including those with the highest stocking rate and grass intake per hectare, and more than USD 225 Economic Farm Surplus (EFS) per hectare with the lower unitary cost. Other two types exhibited intermediate economic performance (HS-2 and HG-1) with EFS close to zero and unitary cost similar to price. And one type (HS-1) displayed the worst economic performance, with negative indicators and the largest number of farms with very low productivity.

Soybean oil, linoleic acid source, in lamb diets: carcass traits and meat quality.

We developed a study to determine the ideal level of inclusion of soybean oil (SBOil) in the diet without affecting the quantitative and qualitative parameters of the carcass and meat of lambs in a feedlot system; therefore, determining the ideal level of inclusion. Forty male lambs (Santa Inês breed) were used. The initial body weight and age averaged 34.88 ± 3.19kg and 5months, respectively. Experimental units (lambs) were randomly distributed in 5 different diets: inclusion levels of SBOil: 0, 30, 60, 90, and 120g/kg of dry matter (DM). The SOil inclusion reduced the DM intake (P < 0.001), Total digestible nutrients (P = 0.004), and crude protein (P < 0.001). Total weight gain (P < 0.001) decreased with the SBOil inclusion and subcutaneous fat thickness (P = 0.017) showed the same behaviour. The final body weight decreased by 42.9g/kgDM until the inclusion level of 30g/kgDM; from this level it was reduced by 145g/kgDM. The hot and cold carcass weights (P = 0.013) decreased by 36.6g/kgDM after including 30g/kgDM of SBOil. Meat physicochemical composition was not altered (P > 0.05). Lower meat tenderness values ​​were obtained at the levels of 60 and 90g/kgDM. The inclusion above 30g/kgDM decreased meat tenderness. It is concluded that soybean oil should be included up to 30g/kgDM in diets. It is important to note that with diets with 60% concentrate, SBOil levels greater than 30g/kgDM promote yield losses.

Individualised feeding of concentrate supplement according to milk yield did not increase milk production in pasture-grazed cows near peak lactation

ABSTRACT In grazing systems, feeds other than pasture are often used to increase dry matter intake and milk production. The study aimed to evaluate the effect of individually feeding pasture-grazed dairy cows near peak lactation based on their individualised milk production compared with a flat-rate feeding regime. All cows in the flat-rate treatment were offered 4 kg wet weight (3.6 kg DM) of concentrate/d. In the individualised feeding treatment, cows were offered 6, 4, and 2 kg wet weight/d (5.4, 3.6 and 1.8 kg DM/d) in the high, moderate, and low production groups, respectively. Individualised feeding of concentrates based on cow milk production did not alter milk or milk component yield at a herd level, but increased milk yield and tended to increase yield of fat, protein, and lactose in cows in the medium milk yield tertile. Individualised feeding reduced milk protein yield in cows in the low milk yield tertile, compared with flat rate feeding. The results do not support individualised feeding in grazing dairy systems where the maximum level of concentrate offered/ is ≤ 6 kg DM/d and milk production/cow ≤30 kg milk/d or ≤2.5 kg fat and protein/d.

PSIX-23 Evaluation of number of goats grazing grass-based pasture for estimation of methane emission using GreenFeed system

Abstract The objective of this study was to evaluate the number of goats in pasture grazing on methane (CH4) emissions estimates using the GreenFeed system (GFS). The study involved growing meat goats, approximately 1.2 yr old and body weight (BW) of 23.9 ± 0.63 kg, over seven 2-wk periods. In periods 1, 2, and 3, 24 goats were used (Treatment 1: G-24), while periods 4 and 5 involved 18 goats (Treatment 2: G-18), and periods 6 and 7 used 12 goats (Treatment 3: G-12). The pasture area was divided into three paddocks for grazing, except during gas measurements in a stationary respiration calorimetry system (SCS) room for 2 d, where goats were fed fresh forage from the same pastureland. The GFS was programmed to dispense pellets and measured gas at specific intervals of the day (i.e., at 0700-0800 h, 1300-1400 h, 1900-2000 h, and 0100-0200 h), provided 120 g/d of concentrate pellets to attract goats for gas measurements. Statistical analysis using mixed model procedures of SAS included SCS data from preceding and succeeding periods as covariates for GFS gas data analysis. Daily dry matter (DM) intake was greater (P &amp;lt; 0.001) in G-12 compared with G-24 and G-18, but when expressed g/kg BW, intakes were similar (P = 0.081) across treatments. Conversely, digested DM and gross energy intakes were greater (P &amp;lt; 0.001) in G-24 than in G-18 and G-12 (494, 509, and 577 g/d and SE = 21.3 and 7.91, 8.10, and 9.20 MJ/d and SE = 0.359 for G-24, G-18, and G-12, respectively). Daily CH4 production was unaffected (P = 0.254) by treatment (26.6, 25.2, and 26.1 g/d; SE = 0.819), despite variations in daily GFS visits by goats (3.26, 2.61, and 2.53 visits/d and SE = 0.106 for G-24, G-18, and G-12, respectively; P &amp;lt; 0.001). However, CH4 emissions in g/kg DM intake or digestible DM intake differed among treatments, with G-18 intermediate between G-24 and G-12 (35.6, 33.4, and 32.0 g/kg DM intake, SE = 1.02, P = 0.024; 54.1, 51.2, and 48.9 g/kg digestible DM intake, SE = 1.71, and P &amp;lt; 0.001 for G-24, G-18, and G-12, respectively). Carbon dioxide production, expressed in g/d and g/kg DM intake, was greater in G-12 and G-18 compared with G-24. Heat production ranked greatest in G-12, followed by G-18 and G-24. Regardless of treatment, CH4 emissions in g/d, g/kg DM intake or g/kg digestible DM intake were greater in GFS than in SCS (25.5 and 9.56 g/d, 33.8 and 14.4 g/kg DM intake, and 51.2 and 23.8 g/kg digestible DM intake for GFS and SCS, respectively; P &amp;lt; 0.001). In conclusion, differences in CH4 emissions in g/kg DM intake and digestible DM intake among treatments suggests that number of animals in grazing pasture may influence CH4 emission estimates in goats.

PSX-22 Boosting techniques for prediction of dry matter intake of cattle in confinement settings and SHAP analysis on the models’ output

Abstract Measurement of individual dry matter intake (DMI) is critical to improving the management of the beef herd and is necessary to determine the feed efficiency of individual cattle. Combining machine learning models and proxies for DMI (e.g., water intake, body weight, climatic variables) has the potential to replace the need for dedicated feed intake equipment. It would also open the possibility of measuring DMI in situations like grazing where quantifying DMI directly is not possible. In this study, we examined the relationship between DMI, animal variables and environmental variables. In this study, we developed and tested machine learning models based boosting techniques to develop approaches to predict DMI in cattle, using the same data we have previously published results from Random Forest techniques in the past. The dataset included both bulls and steers. The developed models include both regular boosting regression models and random effects boosting models. The regular boosting technique models such as gradient boosting regression, light gradient boosting regression, extreme gradient boosting regression. Similarly, random effects boosting machine learning model Gaussian process boosting (GPBoost) was developed to consider the random effects associated with the intake behavior of the animals. The extreme gradient boosting model outperformed other regular boosting regression models with a r2 of 0.81 and 0.48 on training and testing datasets respectively. However, it does not consider the random effects associated with the longitudinal nature of the animal intake and weather variables and prone to overfitting. GPBoost model variants were tested and developed to avoid overfitting and to incorporate a random effects model, which we propose as the overall best performing model. The GPBoost generalized well on the training and testing datasets with r2 scores of 0.55 and 0.54 respectively. To further understand the model’s performance on the unseen dataset, we used SHAP analysis on the GPBoost. The SHAP analysis revealed that water intake, full body weight and age of the animals contributed significantly to predicting unseen data.