Animal & Range Sciences

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The curricula in animal science provide students with a firm foundation in the biological and natural sciences, animal breeding, reproductive physiology, nutrition, and livestock production and management. Natural Resources & Rangeland Ecology focuses on managing the interaction of livestock, and wildlife and their rangeland habitats. Emphasis is placed on soil, water and vegetation attributes which influence habitat ecology and management of livestock and wildlife.

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Short Communication: artificially reared ewes cannot be distinguished from natural reared ewes based on observed maternal behavior or lamb weaning weights
(Oxford University Press, 2024-09) Posbergh, Christian J.; Miles, Asha M.; Pettifor, Natasha L.; Thonney, Michael L.
Artificially rearing lambs is an important component of United States sheep production as some flocks select for increasing litter size to boost productivity. However, there is a conception among shepherds that artificially reared ewe lambs will ultimately result in poor mothers since they were not naturally raised. The objective of this study was to determine if differences in maternal behavior could be detected between ewes raised artificially and those raised naturally and if dam rearing type had an impact on lamb growth performance. Forty-eight ewes were enrolled comprised of 4 equal sized groups: artificially reared primiparous, naturally reared primiparous, artificially reared multi-parous, and naturally reared multi-parous. Ewes were observed using remote cameras to record maternal behaviors toward the lambs during and shortly after parturition. Behavior of 29 ewes during the first hour after parturition was analyzed. Independent multivariable regression models were evaluated for: proportion of time spent grooming, proportion of time spent helping the lambs nurse, number of helpful bouts, and the number of negative bouts. No statistically significant difference (P < 0.05) was detected between artificially reared and naturally reared ewes for the proportion of time spent grooming and the proportion of time spent helping the lambs nurse. Historical flock data were utilized to evaluate lamb growth between artificially and naturally reared ewes. No detrimental associations between artificially reared ewes and lamb weaning weights were observed. This study shows that artificially reared ewes are no different in terms of mothering behaviors and may be used as potential replacement candidates.
The Use of Pulmonary Arterial Pressure (PAP) for Improved Beef Cattle Management
(MDPI AG, 2024-08) Stearns, Kaylen; DelCurto-Wyffels, Hannah; Wyffels, Sam; Van Emon, Megan; DelCurto, Tim
Pulmonary arterial pressure (PAP) determines cattle’s susceptibility to High Altitude Disease (HAD), also known as Brisket Disease, High Mountain Disease, and right-sided heart failure (RHF). This non-infectious disease causes pulmonary hypertension due to hypoxia. PAP measures the resistance of blood flow through the lungs. It is estimated that 1.5 million head of cattle are raised in high-altitude environments (above 1500 m), and HAD accounts for 3–5% of calf death loss yearly. In addition, there have been increasing concerns about feedlot cattle succumbing to RHF at moderate elevations. This review focuses on the historical background, explanation of PAP measurement and scores, genetic implications, and the relationship between PAP and economically relevant traits. Specifically, traits such as gestation length, birth weight, weaning weight, and yearling weight may impact PAP scores. In addition, environmental effects and other factors impacting PAP score variations are discussed. Information gaps and research needs are addressed to determine where missing information could improve the understanding of PAP while also benefiting beef cattle producers in high-elevation production systems.
Sensory and volatile aromatic compound differences of paired lamb loins with 0 or 14 day dry aging
(Elsevier BV, 2024-04) Wall, Kayley; Kerth, Chris; Miller, Rhonda; Boles, Jane
Flavor of lamb is a major driving factor in eating satisfaction. Dry aging has been used in beef to alter flavor and tenderness. The objective of the research was to determine what affect dry aging had on flavor attributes and the volatile compounds that influence the perception of flavor. Lambs (n = 10) were fed an alfalfa-based concentrate diet for 60 d prior to harvest. Loins were obtained from both sides of the carcass and randomly assigned to an aging treatment; no age (boned and frozen day 0) or 14 d of dry age in cold storage (4°C, 55%RH). Descriptive flavor profile panel evaluated samples and volatile compounds were analyzed from cooked samples. No differences were detected by descriptive flavor panel between fresh and dry aged loin chops for most flavor attributes. However, aged loins were rated saltier than loins not aged. Additionally, aged loin chops tended to have a greater intensity score for mutton and green attributes. Aldehydes were the greatest proportion of the volatile aroma compound chemical classification recovered and identified from the lamb samples. Dry-aged lamb loins yielded greater thiobis-methane (a sulfurous, fishy aroma) than loins without ageing. As expected, muscle fiber tenderness as evaluated by sensory panel was greater for aged loin chops than no age (12.7 and 10.0, respectively). Aged loin chops tended to be juicier as well. Aging in aerobic conditions for up to 14 d can improve tenderness in lamb without significantly impacting flavor, however, there is a tendency to increase the mutton and green flavors with dry aging.
Effects of pelleted versus loose salt-limited protein supplement on supplement intake behavior of yearling heifers grazing dryland pastures
(Oxford University Press, 2022-08) White, Hayley C; Van Emon, Megan L; DelCurto-Wyffels, Hannah M; Wyffels, Samuel A; DelCurto, Timothy
The objectives of this study were to evaluate the impacts of supplement form on supplement intake behavior, body weight (BW), and body condition score (BCS) change of yearling heifers grazing dryland pastures during the summer. In each of the two years, Angus crossbred heifers (14 mo of age; year 1, N = 57, BW = 449 ± 3.60 kg; year 2, N = 58, BW = 328 ± 3.57 kg) were used in a 84-d completely randomized design evaluating the following treatments: 1) control, no supplement; 2) salt-limited supplement in pelleted form; and 3) a salt-limited supplement in loose form. Individual supplement intake, and time spent at the feeder were measured throughout the course of the study using a SmartFeed Pro self-feeder system (C-Lock Inc., Rapid City, SD, USA). On days 0, 42, and 84, the heifers were weighed, and body condition scored following a 16-h shrink. Supplementation and form of supplement did not influence (P ≥ 0.62) BW change for yearling heifers within or across study grazing periods. Body condition score was not influenced (P ≥ 0.26) by supplementation and form within the 0 to 42 (period 1) or 42 to 84 (period 2)-d periods but displayed a treatment by year interaction (P < 0.01) for the 84-d summer grazing period. Supplement intake (kg/d and g/kg BW) displayed a treatment × period interaction (P < 0.01). Supplement intake (kg/d) of heifers consuming pelleted supplement was 28% and 31% greater (P ≤ 0.02) than heifers consuming loose supplement in periods 1 and 2, respectively. Supplement intake (g/kg BW) of heifers consuming pelleted supplement was 24% and 32% greater (P ≤ 0.05) than heifers consuming loose supplement in periods 1 and 2, respectively. Overall, across both years, supplement intake in period 1 was less than half (P < 0.01) that of period 2, averaging 0.50 and 1.14 kg/day, respectively. Variation in supplement intake (% CV) was greater (P = 0.03) in period 1 compared to period 2, averaging 119% and 91%, respectively. In addition, variation in supplement intake was greater (P = 0.03) in year 2 than year 1, averaging 122% and 88%. Our results suggest that salt-limited supplements have a high degree of intake variation and pelleting could have a masking effect as indicated by the greater intake and intake rate of supplement with heifers consuming the pelleted supplement.
Adaptive constraints at the range edge of a widespread and expanding invasive plant
(Oxford University Press, 2023-12) Fletcher, Rebecca A.; Atwater, Daniel Z.; Haak, David C.; Bagavathiannan, Muthukumar V.; DiTommaso, Antonio; Lehnhoff, Erik; Paterson, Andrew H.; Auckland, Susan; Govindasmo, Prabhu; Lemke, Cornelia; Morris, Edward; Rainville, Lisa; Barney, Jacob N.
Identifying the factors that facilitate and limit invasive species’ range expansion has both practical and theoretical importance, especially at the range edges. Here, we used reciprocal common garden experiments spanning the North/South and East/West range that include the North American core, intermediate and range edges of the globally invasive plant, Johnsongrass (Sorghum halepense) to investigate the interplay of climate, biotic interactions (i.e. competition) and patterns of adaptation. Our results suggest that the rapid range expansion of Johnsongrass into diverse environments across wide geographies occurred largely without local adaptation, but that further range expansion may be restricted by a fitness trade-off that limits population growth at the range edge. Interestingly, plant competition strongly dampened Johnsongrass growth but did not change the rank order performance of populations within a garden, though this varied among gardens (climates). Our findings highlight the importance of including the range edge when studying the range dynamics of invasive species, especially as we try to understand how invasive species will respond to accelerating global changes.
Suppression force-fields and diffuse competition: competition de-escalation is an evolutionarily stable strategy
(The Royal Society, 2023-08) Atwater, Daniel Z.
Competition theory is founded on the premise that individuals benefit from harming their competitors, which helps them secure resources and prevent inhibition by neighbours. When multiple individuals compete, however, competition has complex indirect effects that reverberate through competitive neighbourhoods. The consequences of such ‘diffuse’ competition are poorly understood. For example, competitive effects may dilute as they propagate through a neighbourhood, weakening benefits of neighbour suppression. Another possibility is that competitive effects may rebound on strong competitors, as their inhibitory effects on their neighbours benefit other competitors in the community. Diffuse competition is unintuitive in part because we lack a clear conceptual framework for understanding how individual interactions manifest in communities of multiple competitors. Here, I use mathematical and agent-based models to illustrate that diffuse interactions—as opposed to direct pairwise interactions—are probably the dominant mode of interaction among multiple competitors. Consequently, competitive effects may regularly rebound, incurring fitness costs under certain conditions, especially when kin–kin interactions are common. These models provide a powerful framework for investigating competitive ability and its evolution and produce clear predictions in ecologically realistic scenarios.
Conceptualization and implementation of the Fiber Utilization and Cell Wall Constituents Symposium
(Oxford University Press, 2023-01) Smith, W B; Wyffels, S A; Gekara, O J
Understanding how ruminants break down plant cell walls and digest plant fibers can help improve the efficiency of livestock production
Molecular Pathways for Muscle and Adipose Tissue Are Altered between Beef Steers Classed as Choice or Standard
(MDPI AG, 2023-06) Haderlie, Sarah A.; Hieber, Jordan K.; Boles, Jane A.; Berardinelli, Berardinelli; Thomson, Jennifer M.
Targets for finished livestock are often determined by expected fat, either subcutaneous or intramuscular. These targets are used frequently to improve eating quality. Lower intramuscular fat, lack of product uniformity, and insufficient tenderness can negatively impact beef acceptability. This study aimed to investigate the differences in gene expression that alter metabolism and intercellular signaling in the muscle and adipose tissue in beef carcasses at different fat endpoints. In this study, longissimus thoracis muscle samples and adipose tissue were collected at harvest, and RNA was extracted and then sequenced using RNAseq. Differential expression was determined using edgeR, and p-values were adjusted using the Benjamini–Hochberg method. A corrected p-value of 0.005 and log2 (fold change) of >1 were the threshold to identify differential expression. Comparison between intermuscular and subcutaneous fat showed no differences in the genes activated in the two adipose tissue depots, suggesting that subcutaneous fat was an adequate sample. Carcass data allowed the classification of carcasses by USDA quality grades (marbling targets). In comparing muscle from Standard and Choice carcasses, 15 genes were downregulated, and 20 were upregulated. There were 49 downregulated and 113 upregulated genes comparing adipose tissue from Standard and Choice carcasses. These genes are related to the metabolism of fat and energy. This indicates that muscle transcript expression varies less than adipose. In addition, subcutaneous fat can be used to evaluate transcript changes in fat. However, it is unclear whether these fat tissues can be used as surrogates for marbling.
Residual effect of narasin on feed intake and rumen fermentation characteristics in Nellore steers fed forage-based diet
(Oxford University Press, 2023-01) Bortolanza Soares, Letícia Carolina; Marques, Rodrigo S; Vaz Pires, Alexandre; Alves Cruz, Vinicius; Ogg, Makayla Anne; Limede, Arnaldo Cintra; Gonzales Dias Junior, Paulo César; Jorge dos Santos, Isabela; Garcia de Assis, Rhaíssa; Gouvêa, Vinícius N; Maia Ferreira, Evandro; Montanher Polizel, Daniel
This study aimed to evaluate the residual effect of narasin on intake and ruminal fermentation parameters in Nellore cattle fed a forage-based diet. Thirty rumen-cannulated Nellore steers [initial body weight (BW) = 281 ± 21 kg] were allocated to individual pens in a randomized complete block design, with 10 blocks and 3 treatments, defined according to the fasting BW at the beginning of the experiment. The animals were fed a forage-based diet containing 99% Tifton-85 haylage and 1% concentrate. Within blocks, animals were randomly assigned to one of three treatments: (1) forage-based diet without addition of narasin (CON; n = 10), (2) CON diet plus 13 mg of narasin/kg DM (N13; n = 10), or (3) CON diet plus 20 mg of narasin/kg DM (N20; n =10). The experiment lasted 156 d and was divided into two periods. The first period lasted 140 d and consisted of the daily supply of narasin. In the second period (last 16 d), the animals were not supplemented with narasin when the residual effect of the additive was evaluated. The treatments were evaluated by linear and quadratic orthogonal contrasts. The results were reported as least square means and the effect was considered significant when P ≤ 0.05. No treatment × day interaction was identified for dry matter intake (P = 0.27). There was a treatment × day (P ≤ 0.03) interaction after narasin removal for the molar proportion of acetate, propionate, ac:prop ratio, and ammonia nitrogen. The inclusion of narasin decreased linearly (P < 0.01) the molar proportion of acetate (P < 0.01), and this effect persisted until day 5 after narasin withdrawal (P < 0.01). Narasin inclusion linearly increased the molar proportion of propionate (P < 0.04), and linearly decreased (P < 0.01) ac:prop ratio up to 5 d after removing narasin from the diets. No treatment effects were observed (P > 0.45) on days 8 and 16 after the withdrawal. Narasin linearly decreased ammonia nitrogen up to 1 day after withdrawal (P < 0.01). In conclusion, the use of narasin for a prolonged period (140 d) resulted in a residual effect on rumen fermentation parameters after the removal of the additive from the diets.
Effects of lasalocid, narasin, or virginiamycin supplementation on rumen parameters and performance of beef cattle fed forage-based diet
(Oxford University Press, 2023-04) Arantes Miszura, Alexandre; Marques, Rodrigo S; Montanher Polizel, Daniel; Ieda Cappellozza, Bruno; Alves Cruz, Vinicius; Ogg, Makayla Anne; Roman Barroso, José Paulo; Bagio Oliveira, Gabriela; Storti Martins, André; Cintra Limede, Arnaldo; Maia Ferreira, Evandro; Gouvêa, Vinícius N; Vaz Pires, Alexandre
Two experiments were designed to evaluate the impacts of supplementing lasalocid (LAS), narasin (NAR), or virginiamycin (VRM) on rumen fermentation parameters, apparent nutrient digestibility, and blood parameters (Exp. 1), as well as feed intake and performance (Exp. 2) of Nellore cattle consuming a forage-based diet. In Exp. 1, 32 rumen-fistulated Nellore steers (initial shrunk body weight [BW] = 355 ± 4.4 kg) were assigned to a randomized complete block design. Within block, animals were randomly assigned to one of four treatments: 1) forage-based diet without feed additives (CON), 2) CON diet plus 13 mg/kg of dry matter (DM) of NAR, 3) CON diet plus 20 mg/kg of DM of sodium LAS, or 4) CON diet plus 20 mg/kg of DM of VRM. No treatment effects were detected (P ≥ 0.32) for intake and apparent digestibility of nutrients. Steers fed NAR had the lowest (P ≤ 0.01) molar proportion of acetate on day 28, 56, and 112 vs. CON, LAS, and VRM steers, whereas acetate did not differ (P ≥ 0.25) between LAS, VRM, and CON steers from day 28 to 84. On day 112, steers fed LAS had a lower (P < 0.02) molar proportion of acetate vs. VRM and CON, whereas it did not differ between CON and VRM (P > 0.33). Steers receiving NAR had a greater (P ≤ 0.04) ruminal propionate vs. CON, LAS, and VRM, whereas LAS steers had greater (P < 0.04) propionate vs. CON and VRM steers on day 28 and 112, and it did not differ (P > 0.22) between CON and VRM. In Exp. 2, 160 Nellore bulls were blocked by initial shrunk BW (212 ± 3.1 kg) in a 140-d feedlot trial. Diets contained the same treatments used in Exp. 1. Bulls fed NAR had greater (P < 0.02) average daily gain (ADG) vs. CON and VRM, and similar (P = 0.17) ADG between NAR and LAS, whereas ADG did not differ (P > 0.28) between LAS, VRM, and CON bulls. A treatment effect was detected (P = 0.03) for dry matter intake, being greater in NAR vs. CON, LAS, and VRM bulls, and similar (P > 0.48) between CON, LAS, and VRM bulls. A tendency was detected (P = 0.09) for feed efficiency, which was greater (P < 0.02) in NAR bulls vs. CON and VRM, and similar (P = 0.36) between NAR and LAS bulls. From day 112 to 140, bulls receiving NAR were heavier (P < 0.03) vs. CON, LAS, and VRM bulls, but no differences were observed (P > 0.51) between CON, LAS, and VRM bulls. Collectively, ruminal fermentation profile and intake were impacted by NAR supplementation, which partially contributed to the enhanced performance of Nellore bulls receiving a forage-based diet.

Animal & Range Sciences

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