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Sustainable Management of Ruminants: Feed Utilization, Nitrogen Dynamics, Physiology, and Metabolism

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A special issue of Animals (ISSN 2076-2615). This special issue belongs to the section "Animal Nutrition".

Deadline for manuscript submissions: 30 April 2025 | Viewed by 5958

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Special Issue Editors

Dr. Omar Al-Marashdeh

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Guest Editor

Faculty of Agriculture and Life Sciences, Lincoln University, P.O. Box 85084, Lincoln 7647, New Zealand
Interests: ruminant nutrition; nitrogen metabolism; feed utilization; sustainable farming

Dr. Arjan Jonker

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Guest Editor

AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
Interests: ruminant nutrition; feed/forage science; greenhouse gas emissions
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Special Issue Information

Dear Colleagues,

This Special Issue aims to explore cutting-edge research and advancements in the sustainable management of ruminants, focusing on key aspects such as feed utilisation, nitrogen dynamics, physiology, and metabolism. We invite contributions that explore innovative strategies for optimising ruminant nutrition, enhancing feed efficiency, and mitigating environmental impacts associated with nitrogen loss and greenhouse gas emissions.

Topics of interest include novel feed formulations (from especially human non-edible feeds/forages), advancements in nutrient utilisation technologies, physiological adaptations to varying dietary inputs, and sustainable approaches to managing nitrogen and carbon cycles within ruminant production systems. This publication aims to foster a comprehensive understanding of sustainable ruminant management practices, contributing to the development of environmentally responsible and economically viable livestock production systems.

We invite researchers, practitioners, and policymakers to submit their latest findings to advance the knowledge frontier in this critical area.

Dr. Omar Al-Marashdeh
Dr. Arjan Jonker
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Animals is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

sustainable farming
feed utilisation
ruminant management
nitrogen metabolism and excretion
greenhouse gas emissions

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Published Papers (7 papers)

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12 pages, 478 KiB

Open AccessArticle

The Effects of a Small Dose of Tannin Supplementation on In Vitro Fermentation Characteristics of Different Forages

by Sytske de Jong, Fabiellen C. Pereira, Alejandro R. Castillo, Wilbert F. Pellikaan and Pablo Gregorini

Animals 2025, 15(9), 1269; https://doi.org/10.3390/ani15091269 (registering DOI) - 29 Apr 2025

Abstract

Pastoral systems in New Zealand are under societal pressure due to their increasing negative environmental impact in terms of greenhouse gas emissions. This study was conducted to investigate the effects of supplementing a mixture containing hydrolysable and condensed tannins on the in vitro fermentation characteristics and gas production of three different forages, Lolium perenne, Medicago sativa, and Plantago lanceolata. Three fermentation runs of 48 h were conducted using the ANKOM gas production technique, with each pertaining to a particular forage with or without (control) tannin. Tannins were added to the fermentable substrate (i.e., forage) at a level of 0.3%. For each run, rumen fluid was collected from two fistulated Holstein Friesian × Jersey cows. The ANKOM RF gas production modules were used to monitor gas pressure and temperature every 5 min. At the end of each run, the pH of the fluid was measured, gas vials were taken for methane (CH₄) measurements and liquor samples were taken to measure volatile fatty acids (VFA) and NH₃ concentrations. The addition of tannins reduced the fractional rate of gas production for alfalfa (p ≤ 0.04) but increased it for ryegrass and plantain. There was a tendency for reduced gas production for ryegrass when tannins were added (p = 0.10). There was also a tendency for CH₄ production to reduce (p < 0.10) and N₂O to increase (p = 0.10) when tannins were added. Iso-butyrate tended to be lower for ryegrass control than to ryegrass with tannins (p = 0.08). Valerate concentration was lower for plantain control than to plantain with tannins. No effects were detected for gas composition (p > 0.05) or VFA concentrations (p > 0.05) when fermenting alfalfa. Under the condition of this study, these results may suggest that low-level tannin addition to the diet may affect rumen-fermentation pattern with a potential reduction of CH₄production in Lolium perenne-based diets. Further research is required on the effect of low levels of tannin supplementation under ex vitro and in vivo conditions as tannin supplementation effects might be substrate-dependent. Full article

(This article belongs to the Special Issue Sustainable Management of Ruminants: Feed Utilization, Nitrogen Dynamics, Physiology, and Metabolism)

14 pages, 3031 KiB

Open AccessArticle

Physiological and Histological Responses of Awassi Lambs to High Dietary Organic Copper Supplementation

by Osama A. Saeed, Mohanad A. Shareef, Hassan M. Alnori, Teik K. Leo, Mohammed A. Al-Bayar, Idham A. Abed and Omar K. Attallah

Animals 2025, 15(7), 1066; https://doi.org/10.3390/ani15071066 - 7 Apr 2025

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Abstract

This study investigated the effects of high dietary organic copper supplementation on growth performance, mineral metabolism and organ histology in male Awassi lambs. Fifteen lambs with similar body weight (16 ± 1.53 kg) were assigned to three groups: a control group (T1) receiving a basal diet, and two treatment groups (T2 and T3) supplemented with 0.5 g and 1 g of organic copper per kg DM, respectively. The total dietary copper concentrations were 6.18, 81.68 and 156.75 ppm in T1, T2, and T3 groups, respectively. The basal diet, composed of soybeans, wheat, and barley, provided 2.4 Mcal/kg metabolizable energy and 14% crude protein. High dietary copper supplementation had no significant impact on growth performance and body biometric measurements. Testicular length was increased in T3 lambs. Mineral analysis showed increased hepatic copper concentrations in T2 and T3 lambs. Kidney copper levels remained within normal ranges, while renal zinc concentrations declined in T2 and T3 lambs. Gene expression analysis demonstrated upregulation of ATP7A and ATP7B genes in T3 lambs, indicating a cellular adaptation to elevated copper levels, while IGF1 expression remained unchanged. Histological assessments, however, revealed hepatic and renal changes in T3 lambs. Overall, high dietary organic copper supplementation, particularly at 1 g Cu/kg DM, increases copper retention and may support reproductive health in Awassi lambs. However, excessive intake poses risks of liver and kidney damage, highlighting the need for careful dietary management. Full article

(This article belongs to the Special Issue Sustainable Management of Ruminants: Feed Utilization, Nitrogen Dynamics, Physiology, and Metabolism)

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17 pages, 889 KiB

Open AccessArticle

Presentation (Chopped Versus Ground and Pelleted) of a Low-Quality Alfalfa Hay in Sheep: Effects on Intake, Feeding Behaviour, Rumen Fill and Digestion, and Passage

by Antonio de Vega, Josep Gasa, Carlos Castrillo and José Antonio Guada

Animals 2025, 15(4), 541; https://doi.org/10.3390/ani15040541 - 13 Feb 2025

Viewed by 468

Abstract

A voluminous amount of knowledge has been collected about the effects of the rate and amount of intake and of the rate and amount of digesta flow out of the rumen on rumen fill and, hence, intake. However, the mechanisms by which small particles in the rumen are selected for passage have not been clearly identified. Grinding and pelleting have been alleged to either enhance or reduce entrapment; hence, the relationships between particle size and digestion and passage kinetics are not sufficiently clear, as it is not the effect of rumen digesta particle size on marker dilution kinetics. On these grounds, the aim of the present experiment was to examine the behaviour of small particles within the rumen and determine if their retention time by passage or digestion pathways alter under pelleting and control intake. In the present experiment, the effects of a low-quality alfalfa hay presentation (chopped vs. ground and pelleted) on intake, feeding behaviour, rumen fill and digestion, and passage were assessed in adult wethers. Pelleting increased intake without alteration of either the maximum amount of digesta present in the rumen or degradation rates. The faster dilution rate of the liquid phase with the pelleted hay, likely including significant amounts of particles <0.15 mm, should be the main factor for the higher intake with this diet. Full article

(This article belongs to the Special Issue Sustainable Management of Ruminants: Feed Utilization, Nitrogen Dynamics, Physiology, and Metabolism)

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21 pages, 4154 KiB

Open AccessFeature PaperArticle

Utilization of Anabolic Implants and Individual Supplementation on Muscle Growth and Protein Turnover During Backgrounding of Beef Steers

by J. Luke Jacobs, Elizabeth Leonard, Nishanth Tharayil and Susan K. Duckett

Animals 2025, 15(4), 513; https://doi.org/10.3390/ani15040513 - 11 Feb 2025

Viewed by 693

Abstract

Weaned Angus-cross steers (n = 69; body weight [BW] = 233 ± 29 kg) were used for the following purposes: (1) develop an assay to measure 3-methylhistidine (3MH) in blood samples to monitor changes in protein turnover, and (2) evaluate the effects of an implant (Revalor-G, 40 mg of trenbolone acetate, 8 mg of estradiol) or an implant plus individual supplementation via SuperSmart Feeder (SSF; C-Lock Inc., Rapid City, SD, USA) on animal growth, muscle growth, and nitrogen retention patterns in backgrounded beef steers. Steers were blocked by weight, trained to precision supplementation via SSF, and then assigned to one of three treatments: (1) grazing only [G], (2) grazing with implant [GI], or (3) grazing with implant plus individual animal supplementation via SSF at 0.75% BW [GIS] for 56 d of grazing study. Steers grazed a cowpea and pearl millet mixture until d 42, when forage became limiting, and steers were transitioned to an oat and annual ryegrass baleage. Steers were weighed and blood was collected every 14 d to determine plasma urea nitrogen (PUN), creatinine (CREAT), and 3-methylhistidine (3MH) concentrations. Ultrasound measurements of ribeye area (REA) were collected on d 0, 28, and 56. Data were analyzed using the GLIMMIX with treatment, day, and two-way interaction in the model. A novel, robust method for the determination of 3MH was developed and validated. The development of this 3MH method allows us to monitor changes in protein turnover in cattle over time, a metric which is related to production efficiency. A treatment-by-day interaction (p = 0.0050) was observed for BW and REA. Steer BW did not differ (p > 0.05) on d 0, 14, or 28 between treatments; however, on d 42, GI and GIS steers had a greater (p < 0.01) BW than G steers. On d 56, BW was greater (p < 0.0001) for GIS than GI and G, which not differ (p > 0.05). Total BW gain during the 56 d study was greater (p < 0.001) by 54% for GIS compared to GI or G. For GI, the total BW gain was greater (p < 0.01) by 18% compared to G. On d 56, the REA of GI and GIS steers was greater (p < 0.001) than of G steers. Steers in the GI treatment group had a greater PUN and PUN–CREAT ratio concentrations than the GIS steers. Both G and GI steers had greater 3-methylhistidine (3MH) concentrations compared to GIS steers on d 28. Our results demonstrate that the supplementation of implanted steers improves growth and improves nitrogen utilization during backgrounding on forage diets. This research illustrates that animal and muscle growth may be limited in grazing animals implanted with combination implants (estrogenic and androgenic compounds) when supplementation is not included. Full article

(This article belongs to the Special Issue Sustainable Management of Ruminants: Feed Utilization, Nitrogen Dynamics, Physiology, and Metabolism)

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11 pages, 561 KiB

Open AccessArticle

Animal as the Solution II: Phenotyping for Low Milk Urea Nitrogen A1PF Dairy Cows

by Fabiellen C. Pereira, Sagara Kumara, Anita Fleming, Shu Zhan Lai, Ella Wilson and Pablo Gregorini

Animals 2025, 15(1), 32; https://doi.org/10.3390/ani15010032 - 26 Dec 2024

Viewed by 599

Abstract

The societal pressure on intensive pastoral dairying demands the search for strategies to reduce the amount of N flowing through and excreted by dairy cows. One of the strategies that is being currently explored focuses on the animal as a solution, as there are differences in N metabolism between cows even within the same herd. This work was conducted to explore such an approach in A1PF herds in New Zealand and the possibility of identifying A1PF cows that are divergent for milk urea nitrogen (MUN) concentration through phenotyping as a potential viable strategy to reduce N leaching and emissions from temperate dairy systems. Three herd tests were conducted to select a population sample of 200 cows (exhibiting the lowest 100 and highest 100 MUN concentrations). Milk samples were collected from the 200 cows during mid and late lactation to test for milk solids content and MUN. From the 200 cows, urine for urinary N concentration (UN), blood for plasma urea N, total antioxidants (TAS), and glutathione peroxidase (GPx) were collected from the 20 extremes (the lowest 10 and highest 10 MUN concentrations). Milk urea N was greater in cows selected as high-MUN cows (16.2 vs. 14.32 ± 0.23 mg/dL) and greater during late lactation (16.9 vs. 13.0 ± 0.19 mg/dL). Milk solids and fat content were 38% and 20% greater in cows selected as low-MUN cows than in high-MUN cows during mid lactation (p < 0.001). Low-MUN cows had lower UN than high-MUN cows during mid lactation (0.64 vs. 0.88 ± 0.11%). The N concentration in the plasma (p = 0.01) and Tas (p = 0.06) were greater during late lactation. There was a positive relationship between the MUN concentration phenotype used for selection and the MUN concentration for the trial period and MUN concentration and UN concentration during mid and late lactation (p < 0.001). Our results suggest that A1PF cows within a commercial herd can be phenotyped and selected for low-MUN, which may be potentially a viable strategy to reduce N losses to the environment and create healthier systems. Following genetic tracking, those cows can be bred to further promote low-MUN A1PF herds. Full article

(This article belongs to the Special Issue Sustainable Management of Ruminants: Feed Utilization, Nitrogen Dynamics, Physiology, and Metabolism)

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16 pages, 271 KiB

Open AccessArticle

Utilization of Purple Napier Grass Silage on Milk Quality and Blood Antioxidant Activity in Lactating Dairy Goats

by Weerada Meethip, Siwaporn Paengkoum, Narawich Onjai-uea, Sorasak Thongpea, Nittaya Taethaisong, Jariya Surakhunthod and Pramote Paengkoum

Animals 2024, 14(22), 3209; https://doi.org/10.3390/ani14223209 - 8 Nov 2024

Viewed by 1467

Abstract

In this study, our subjects were 18 female crossbred Saanen lactating goats; the goats weighed approximately 43.25 ± 2.35 kg and had been producing milk for 14 ± 2 days. They were assigned to three equally sized experimental groups based on the cycle of the lactation period. In accordance with the randomized complete block design (RCBD), six animals were randomly assigned to the treatments in each block. There were three treatments: (1) control = Napier Pakchong-1 grass silage (NPS); (2) = sweet grass silage (SGS); and (3) = purple Napier silage (PNS). Our findings show that the goats fed with purple Napier grass silage had a higher DM intake (1805.97 g/day) than those that underwent a different treatment (1312.76 and 1443.43 g/day). The goats fed with purple Napier grass silage had higher protein digestibility (79.85) than those fed with Napier Pakchong-1 and sweet grass silage. There were significant differences in the ruminal ammonia nitrogen and blood urea nitrogen. Nevertheless, purple Napier grass silage significantly increased butyric acid 2 and 4 h after feeding and increased the number of microorganisms. In the dairy goats fed purple Napier grass silage, we observed a reduction in protozoa and methanogen populations. The levels of antioxidants shown by the plasma indices differed in the goats fed with purple Napier grass silage and showed enhanced milk composition, higher levels of total antioxidants, superoxide dismutase and glutathione peroxidase in the plasma, reduced protozoa methanogen, and a decreased level of malondialdehyde in the plasma. This study highlights that purple Napier grass silage has the potential to be a beneficial source of roughage for lactating dairy goats. Full article

(This article belongs to the Special Issue Sustainable Management of Ruminants: Feed Utilization, Nitrogen Dynamics, Physiology, and Metabolism)

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19 pages, 3141 KiB

Open AccessEditor’s ChoiceSystematic Review

Can the Inclusion of Forage Chicory in the Diet of Lactating Dairy Cattle Alter Milk Production and Milk Fatty Acid Composition? Findings of a Multilevel Meta-Analysis

by Mancoba C. Mangwe, Racheal H. Bryant, Antonia Olszewski, Hitihamy Mudiyanselage Gayani P. Herath and Omar Al-Marashdeh

Animals 2024, 14(7), 1002; https://doi.org/10.3390/ani14071002 - 25 Mar 2024

Viewed by 1715

Abstract

In traditional ryegrass/white clover (Lolium perenne L./Trifolium repens L.) pastoral systems, forage herbs such as chicory (Cichorium intybus L.) present an opportunity to fill feed deficits during late spring and summer. Although multiple research publications have evaluated the efficacy of chicory for enhancing milk production and milk fatty acid (FA) profile, no publication has quantitatively synthesised the body of research. This systematic review and meta-analysis examined the effect of chicory on milk production and composition, as well as on the milk fatty acid composition of dairy cattle. A total of 29 comparisons from 15 unique research publications involving 597 dairy cattle were used to develop a dataset for analysis. Three-level random-effect and robust variance estimator models were used to account for the hierarchical structure of the data and the dependency of effect sizes within publications. Chicory inclusion increased milk yield when compared to grass-based diets {weighted mean difference (WMD) = 1.07 (95% CI 0.54–1.60) kg/cow/d, p < 0.001}, but it provided a similar milk yield when compared to other forages such as legumes and herbs {dicots; WMD = −0.30, (95% CI −89–0.29) kg/cow/day, p = 0.312}. Increases in milk yield were congruent with differences in DM intake (p = 0.09) and ME intakes (p = 0.003), being similar in chicory-fed and dicot-fed cows but higher than grass-fed cows. Chicory feeding’s effect on milk solids was twice as high during mid lactation {154 days in milk; WMD = 0.13, (95% 0.081–0.175) kg/cow/day, p < 0.001} as during late lactation {219 days in milk; WMD = 0.06, (95% 0.003–0.13) kg/cow/day, p = 0.041}. In line with milk yield, greater and more significant effect sizes were found for alpha linolenic acid {ALA; WMD = 0.20 (95% CI 0.06–0.35) g/100 g FA, p = 0.011} when chicory was compared to grass species only. Comparing chicory with dicots suggests that chicory inclusion did not impact ALA concentrations {WMD = 0.001 (95% CI −0.02–0.2) g/100 g FA, p = 0.99}. There were no differences in conjugated linoleic acid concentration in the milk of cows fed chicory or control diets. The study provides empirical evidence of chicory’s efficacy for improved milk production and milk fatty acid composition. Full article

(This article belongs to the Special Issue Sustainable Management of Ruminants: Feed Utilization, Nitrogen Dynamics, Physiology, and Metabolism)

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