Small Ruminant Research最新文献

{"title":"Colour phenotypes, genotypes and colorimetry of unprocessed North American Huacaya alpaca fibre, and comparisons with some other common natural fibres","authors":"B. Peter Baxter ,&nbsp;Lynn Edens ,&nbsp;Jeremy L. Wear","doi":"10.1016/j.smallrumres.2025.107558","DOIUrl":"10.1016/j.smallrumres.2025.107558","url":null,"abstract":"<div><div>Standardised fibre colorimetry has been used on midside samples, taken over three seasons, of fleeces from 1192 individual North American Huacaya alpacas. The results have been compared with the <em>Alpaca Owners Association</em> colour phenotype coding, and with Mc1R and ASIP genotype data. The analyses show that standardised colorimetry provides accurate phenotyping on average, but measurement imprecision and probable uncertainties associated with subjective colour coding prevents the prediction of such codes from individual measurements, except for the extremes of white and black. The measurements do, however, confirm good correlation between genotypes and colorimetry, thus supporting their use as an inexpensive additional tool for breeders. When compared with published data on other natural fibres - fine and coarse wool, mohair, cashmere, and cotton - the white and beige alpaca fibres show up favourably for whiteness and brightness. Additionally, unlike the other animal fibres, they do not appear to show a significant yellowness versus brightness relationship, which should be environmentally-beneficial from a textile processing perspective. In common with the other animal fibres, they do show a relationship between yellowness and mean fibre diameter, which is probably a physical light-scattering phenomenon, with the finer samples giving whiter results.</div></div>","PeriodicalId":21758,"journal":{"name":"Small Ruminant Research","volume":"250 ","pages":"Article 107558"},"PeriodicalIF":1.6,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the commercial viability of goat milk from a developing country perspective: Implications for consumer preferences, market dynamics, and food security","authors":"Hapuhinne Karunadhipathi Divarathne Mudiyanselage Pabbatha Lankanatha Divarathne ,&nbsp;Thelikada Palliyage Shashika Ranganie Guruge ,&nbsp;Kapugoda Liyanaarachchige Aruni Madushani Jayasinghe ,&nbsp;Prabath Chaminda Abeysiriwardana ,&nbsp;Iruviman Virajith Kuruppu ,&nbsp;Aluthgedara Lahiru Janitha Bandara ,&nbsp;Sharon Rochelle Elmo Johnson","doi":"10.1016/j.smallrumres.2025.107559","DOIUrl":"10.1016/j.smallrumres.2025.107559","url":null,"abstract":"<div><div>Goat milk is a nutritionally rich dairy alternative with growing global demand, yet its commercial presence in Sri Lanka remains minimal. This study assesses the commercial viability of goat milk by examining consumer preferences and market dynamics, using Kundasale in the Kandy District as a case study. Despite its digestibility, hypoallergenic properties, and high micronutrient content, goat milk accounts for a negligible share of national dairy production, reflecting limited consumer awareness and market penetration. Guided by the Fishbein Multi-Attribute Attitude Model and the Theory of Reasoned Action, the study investigates how awareness, attitudes, and socio-economic factors influence consumer intentions toward goat milk consumption. A logistic regression framework models the likelihood of consumer adoption based on those variables. The conceptual framework further outlines the influence of consumer characteristics, perceptions, and economic constraints on purchase decisions. Findings aim to identify key enablers and barriers to goat milk adoption, contributing to policy recommendations for dairy diversification and local enterprise development. By integrating behavioral theory with market analysis, the study addresses a significant knowledge gap in Sri Lanka and offers a replicable approach for evaluating goat milk’s commercial potential in comparable developing economies. The results have broader relevance for global efforts to enhance dairy self-sufficiency, promote functional foods, and support sustainable, small-scale livestock systems.</div></div>","PeriodicalId":21758,"journal":{"name":"Small Ruminant Research","volume":"250 ","pages":"Article 107559"},"PeriodicalIF":1.6,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phenotypic and genetic analyses of parasitological, physiological and immunological indicator traits of gastrointestinal nematode infections in German Merino crossbred lambs","authors":"Rebecca Martin,&nbsp;Johannes Gürtler,&nbsp;Valentin P. Haas,&nbsp;Clara Piefke,&nbsp;Sonja Schmucker,&nbsp;Volker Stefanski,&nbsp;Jörn Bennewitz,&nbsp;Markus Schmid","doi":"10.1016/j.smallrumres.2025.107557","DOIUrl":"10.1016/j.smallrumres.2025.107557","url":null,"abstract":"<div><div>Most sheep have access to pasture but thus are exposed to gastrointestinal nematodes (GIN). One sustainable approach with long-term potential to counteract the currently increasing resistance of GIN towards anthelmintics is the breeding of sheep with better immunocompetence against GIN. The present study investigated parasitological, immunological and physiological indicator traits in a German sheep population consisting of Merino and crossbred lambs. The trial was conducted over two years under field conditions on three farms with two different grazing systems (extensive/intensive) per farm in southern Germany. After stable rearing, lambs were kept on pasture where blood and faecal samples were taken after approximately five weeks after natural infection. Depending on the trait, data of 383–1015 lambs were available for phenotypic and genetic analyses. Estimated heritabilities were 0.15 ± 0.02 for FEC for <em>Trichostrongylidae,</em> 0.09 ± 0.02 for FEC for <em>Nematodirus</em> spp., 0.23 ± 0.03 for dag score and 0.13 ± 0.02 for faecal consistency score, whereas heritabilities for the total immunoglobulin A (IgA) concentration in plasma or faeces were 0.63 ± 0.04 or 0.11 ± 0.06, respectively. The heritability of the production trait average daily gain was 0.09 ± 0.02. Substantial phenotypic variation was observed in all traits. Except for total faecal IgA and average daily gain, heritabilities were significant and low to moderate, hence, indicating clear potential for breeding. The small sample size in combination with the varying infection environments did not allow clear inferences about the relationships between traits despite some significant correlations. However, this is necessary before valid breeding goals can be defined, whereby future studies might benefit from considering the course of infection and antigen-specific immune measures in large samples of purebred sheep.</div></div>","PeriodicalId":21758,"journal":{"name":"Small Ruminant Research","volume":"250 ","pages":"Article 107557"},"PeriodicalIF":1.6,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144271604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Innovative protein sources for sustainable sheep farming: Assesing black soldier fly larvae meal in merino lamb diet","authors":"M.M. Odeon ,&nbsp;V. Fernández-Arhex ,&nbsp;B. García - Falabella ,&nbsp;L. Villar ,&nbsp;V. Caballero ,&nbsp;S. Hara ,&nbsp;A.K. Cancino ,&nbsp;E.S. Villagra","doi":"10.1016/j.smallrumres.2025.107556","DOIUrl":"10.1016/j.smallrumres.2025.107556","url":null,"abstract":"<div><div>The growing global demand for animal-based food poses challenges to sustainability and animal welfare, especially in intensive production systems. This study explores the potential of black soldier fly larvae (BSFL) meal as a sustainable and innovative protein source for Merino lamb diets, offering an alternative to soybean expeller meal. Over a 50-day fattening period, Merino lambs were fed two dietary treatments: soybean expeller meal (S) and BSFL meal. Key metrics were evaluated, including productive performance (body weight, body condition score, feed intake, average daily gain, and feed conversion efficiency), ruminal fermentation profiles, and some stress biochemical indicators (glucose levels, cortisol levels, and plasma protein concentrations). Notably, no significant differences were found between diets in terms of growth performance, ruminal health, or stress markers, suggesting that BSFL meal could be a viable and competitive alternative. These results highlight the potential of BSFL to enhance sustainability in small ruminant production by reducing reliance on environmentally impactful feed ingredients like soybean expeller meal. This study underscores the relevance of BSFL meal in promoting resource efficiency, environmental conservation, and innovative solutions in small ruminant nutrition. These findings open the door to the inclusion of insect use, specifically black soldier fly larvae, in ruminant diets as a viable strategy to improve the sustainability of production systems.</div></div>","PeriodicalId":21758,"journal":{"name":"Small Ruminant Research","volume":"250 ","pages":"Article 107556"},"PeriodicalIF":1.6,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144204619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of changes in homogenisation sequence and stage for sheep milk on physicochemical and microbiological properties and consumer acceptance of kefir","authors":"Figen Özkul Ateş,&nbsp;Firuze Ergin Zeren,&nbsp;Ahmet Küçükçetin","doi":"10.1016/j.smallrumres.2025.107553","DOIUrl":"10.1016/j.smallrumres.2025.107553","url":null,"abstract":"<div><div>The aim of this work is to contribute to the knowledge of the quality of kefir produced from sheep milk, with a particular focus on the effect of homogenisation conditions such as homogenisation sequence and homogenisation stage. The effect of single-stage (150 bar) or double-stage (150/30 bar) homogenisation, both prior to and after heat treatment at 85°C for 15 min, on the physicochemical and microbiological properties and consumer acceptance of kefir produced from sheep milk was investigated. Kefir produced from homogenised sheep milk was stored at 4°C for 30 days. Visual roughness, number of grains, mean perimeter of grains, apparent viscosity, and consistency coefficient were higher, and flow behaviour index and syneresis were lower in kefir produced from heat-treated and subsequently homogenised milk compared to those in kefir produced from milk homogenised before heat treatment, as well as in kefir produced from double-stage homogenised milk compared to those in kefir produced from single-stage homogenised milk. The homogenisation conditions for milk led to statistical differences in the microbiological counts of kefir, which were not microbiologically significant. The appearance and texture scores of the kefir samples increased when double-stage homogenisation was applied instead of single-stage homogenisation to the milk or when the milk was homogenised after heat treatment instead of before heat treatment. This study demonstrated that changing the homogenisation sequence and homogenisation stage for milk altered the physicochemical properties and consumer acceptance of kefir.</div></div>","PeriodicalId":21758,"journal":{"name":"Small Ruminant Research","volume":"250 ","pages":"Article 107553"},"PeriodicalIF":1.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144178856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular detection of benzimidazole resistance in Haemonchus contortus: A comparative analysis of field and abattoir larval isolates from sheep and goats","authors":"Mohamed A. Helal ,&nbsp;Prashant D. Pawar ,&nbsp;Lachhman Das Singla","doi":"10.1016/j.smallrumres.2025.107555","DOIUrl":"10.1016/j.smallrumres.2025.107555","url":null,"abstract":"<div><div>Benzimidazole (BZ) resistance in <em>Haemonchus contortus</em> presents a significant threat to small ruminant production, particularly in developing countries. This study employed molecular techniques to detect BZ resistance in <em>H. contortus</em> larvae isolated from sheep and goats in both field and abattoir settings. Using allele-specific PCR (AS-PCR), we analysed polymorphisms in codon 200 of the β-tubulin isotype 1 gene, complemented by restriction fragment length polymorphism (RFLP) analysis for species verification. In goat larval isolates (n = 156), genotypic analysis revealed 58 % homozygous resistant (RR), 12 % homozygous susceptible (SS), and 30 % heterozygous (RS) larvae. Sheep larval isolates (n = 218) showed a different distribution: 29 % RR, 20 % SS, and 51 % RS.The overall frequency of the resistance allele (R)was notably higher in goat samples (73 %) compared to sheep samples (54 %). These findings indicate widespread BZ resistance in both host species, with a particularly concerning prevalence in goat populations. This study demonstrates the utility of molecular techniques for early resistance detection and highlights the need for targeted anthelmintic management strategies in small ruminant production systems.</div></div>","PeriodicalId":21758,"journal":{"name":"Small Ruminant Research","volume":"250 ","pages":"Article 107555"},"PeriodicalIF":1.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144166333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Replacement of soybean meal with urea in forage cactus diets for lambs: Nitrogen balance, performance, blood parameters, carcass traits, and meat quality","authors":"Fabio Santos do Nascimento ,&nbsp;Ruan Higor dos Anjos Neves ,&nbsp;Marcelo de Andrade Ferreira ,&nbsp;João Paulo Ismerio dos Santos Monnerat ,&nbsp;Ariosvaldo Nunes de Medeiros ,&nbsp;Andreia Fernandes de Souza ,&nbsp;Dorgival Morais de Lima Júnior ,&nbsp;Kelly Cristina dos Santos ,&nbsp;Érica Carla Lopes da Silva ,&nbsp;Marina de Paula Almeida ,&nbsp;Salmo Olegário Lima da Silva ,&nbsp;Francisco Fernando Ramos de Carvalho","doi":"10.1016/j.smallrumres.2025.107554","DOIUrl":"10.1016/j.smallrumres.2025.107554","url":null,"abstract":"<div><div>This study aimed to evaluate the effect of replacing soybean meal with urea in diets based on forage cactus (<em>Opuntia stricta</em>) (Haw.) on the nutrient intake, digestibility, nitrogen balance, blood parameters, performance, carcass traits, and physicochemical and sensory characteristics of the meat of Santa Inês lambs in a feedlot. Forty Santa Inês lambs were used, with an initial body weight of 22.2 ± 2.1 kg, distributed in a completely randomized design. The treatments were diets with 400 g/kg DM forage cactus and increasing levels of urea (0, 7.3, 14.6, and 21.9 g/kg dry matter [DM]) to replace soybean meal. The lambs were confined for 75 days. The lambs with elevated urea levels in the diet showed an increase (P &lt; 0.05) in the intake of crude protein and non-fibrous carbohydrates. As the urea level increased, there was a quadratic increase (P &lt; 0.05) in the amount of urinary nitrogen (N), retained N (% of ingested), serum triglycerides, and albumin. As the urea level increased, there was a linear decrease (P &lt; 0.05) in the average daily gain, empty body weight, cold carcass weight, and the leg muscularity index. The ether extract in the lamb meat and the internal body fat increased (P &lt; 0.05) by adding urea to the diet. In conclusion, in diets with 400 g/kg DM forage cactus, decreases weight gain and cooking losses of meat from Santa Inês lambs in feedlots.</div></div>","PeriodicalId":21758,"journal":{"name":"Small Ruminant Research","volume":"250 ","pages":"Article 107554"},"PeriodicalIF":1.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144195553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of replacing salinomycin with encapsulated Lactococcus lactis EGY_NRC4 on in vitro ruminal fermentation parameters and lactating Barki ewes’ performance","authors":"Hossam H. Azzaz ,&nbsp;Noha A. Hassaan ,&nbsp;Gouda A. Gouda ,&nbsp;Hussein A. Murad ,&nbsp;Yanting Chen ,&nbsp;Ahmed E. Kholif","doi":"10.1016/j.smallrumres.2025.107552","DOIUrl":"10.1016/j.smallrumres.2025.107552","url":null,"abstract":"<div><div>This study assessed the potential of encapsulated <em>Lactococcus lactis</em> EGY_NRC4 as a substitute for salinomycin in the diets of lactating Barki ewes through both in vitro and in vivo experiments. <em>L. lactis</em> EGY_NRC4 is a newly isolated strain that has been characterized for its potential probiotic properties. The strain has been documented in the National Center for Biotechnology Information (NCBI) under the accession number MW856657. Two experiments were conducted: an in vitro study evaluating increasing doses [0, 1, 2, and 3 g/kg dry matter (DM)] of <em>L. lactis</em> (ELB) and salinomycin (0.35, 0.7, and 1 g/kg DM), and an in vivo trial involving 30 lactating ewes assigned to three dietary treatments (control, 2 g/kg <em>L. lactis</em>, or 0.35 g/kg salinomycin) for 60 days. In the in vitro study, ELB significantly increased (<em>p</em> &lt; 0.05) fiber degradability, DM, and organic matter digestibility, while decreasing methane (CH₄) production linearly by up to 33.9 % and increasing carbon dioxide production. In contrast, salinomycin significantly reduced (<em>p</em> &lt; 0.001) gas and CH₄ production by up to ₄8.9 %, enhancing digestibility at lower doses but reducing it at higher concentrations. In the in vivo study, both ELB and salinomycin improved (<em>p</em> &lt; 0.001) nutrient digestibility, with salinomycin showing stronger effects on energy utilization. Blood parameters remained mostly unchanged, except for a significant reduction (<em>p</em> &lt; 0.001) in blood urea nitrogen and cholesterol, and a slight increase (<em>p</em> &lt; 0.05) in glucose levels with the use of ELB, while salinomycin had no effect on cholesterol. Both additives significantly increased (<em>p</em> &lt; 0.001) milk yield by 27.0 % for ELB and 30.3 % for salinomycin, and feed efficiency by approximately 17<em>%</em> (ELB) and 39 % (salinomycin), though they reduced (<em>p</em> &lt; 0.05) milk component content. Fatty acid composition showed minor changes, with ELB increasing (<em>p</em> &lt; 0.05) beneficial unsaturated fatty acids like α-linolenic acid. In conclusion, ELB exhibited promising effects comparable to salinomycin in enhancing performance and digestibility, with distinct impacts on CH₄ emissions and milk composition.</div></div>","PeriodicalId":21758,"journal":{"name":"Small Ruminant Research","volume":"250 ","pages":"Article 107552"},"PeriodicalIF":1.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144204614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of carcass weight for predicting empty body weight in hair sheep in different physiological states","authors":"Ignacio Vázquez-Martínez ,&nbsp;Rosario Salazar-Cuytun ,&nbsp;Jesus Alberto Mezo-Solis ,&nbsp;Darwin Nicolas Arcos-Alvarez ,&nbsp;Antonio de Sousa Brito Neto ,&nbsp;Caio Julio Lima Herbster ,&nbsp;Elzania Sales Pereira ,&nbsp;Alfonso Juventino Chay-Canul","doi":"10.1016/j.smallrumres.2025.107551","DOIUrl":"10.1016/j.smallrumres.2025.107551","url":null,"abstract":"<div><div>The objective of this study was to develop equations to predict empty body weight (EBW) by using fasting body weight (FBW) and hot carcass weight (HCW) for hair sheep in different physiological states. To generate the prediction models, a data set was composed of individual measurements from 278 sheep encompassing suckling males (21 Pelibuey and 15 Katahdin) and females (8 Pelibuey and 12 Katahdin) and growing males (55 Black Belly and 43 Katahdin) and females (56 Black Belly, 13 Dorper, 24 Katahdin, and 21 crossbreed Katahdin × Pelibuey). The coefficients obtained from the linear regression of EBW against FBW and EBW against HCW did not differ between sexes and among breeds (P &gt; 0.05). However, they were influenced by physiological stage (P &lt; 0.001). Four equations were generated for suckling and growing stages: EBW_suckling = -0.15_{(± 0.04)} + 0.91_{(± 0.02)} × FBW (root mean square error (RMSE) = 0.96, R² = 0.99); EBW_growing = -1.50_{(± 0.44)} + 0.91_{(± 0.02)} × FBW (RMSE = 0.96, R² = 0.99); EBW_suckling = 1.84_{(± 0.69)} + 1.46_{(± 0.06)} × HCW (RMSE = 1.94, R² = 0.96); EBW_growing = 5.93_{(± 0.72)} + 1.46_{(± 0.06)} × HCW (RMSE = 1.94, R² = 0.96). The results showed that sex and breed did not influence the linear regression of EBW as a function of FBW and HCW. However, the present study showed that models predicting EBW from FBW and HCW depended on physiological state.</div></div>","PeriodicalId":21758,"journal":{"name":"Small Ruminant Research","volume":"250 ","pages":"Article 107551"},"PeriodicalIF":1.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feed intake and behavioral responses of sheep provided phenylthiocarbamide internally incorporated into feed pellets","authors":"Claire N. Foyil ,&nbsp;J. Bret Taylor ,&nbsp;Joel V. Yelich ,&nbsp;Melinda J. Ellison","doi":"10.1016/j.smallrumres.2025.107528","DOIUrl":"10.1016/j.smallrumres.2025.107528","url":null,"abstract":"<div><div>The objective of this study was to determine the effects of phenylthiocarbamide (PTC), a bittering agent, delivered in feed on dietary intake and behavior in PTC-naive ram lambs (n = 26) and PTC-experienced mature rams (n = 12) previously classified as either super- (n = 3), intermediate (n = 5), or non-PTC tasters (n = 4). For mature rams, four treatment diets were prepared to include 0 (control), 110, 220, and 330 mg PTC/kg. For ram lambs, three treatment diets were prepared to include 0 (control), 180 and 280 mg PTC/kg. Treatment diets were prepared using a pelleted common ground ration (70 % alfalfa hay, 15 % corn, 15 % dehydrated beet pulp, as-fed). Rams received control and PTC diets (0.87 % BW) daily for 30 min in a side-by-side presentation, which was replicated for each concentration. Feed intake duration, number of bucket approaches and switches, sniffs, drinks, head bobs, jerks, shakes, lip smacks and licks were recorded using video surveillance. Consumption of PTC and control diets were similar for all rams (<em>P</em> ≥ 0.22) when measured as a percentage of total diet (control + PTC) consumed. While mature rams began to exhibit signs of PTC aversion at 220 mg/kg (CV = 34.1 %; <em>P</em> = 0.16), ram lambs were indifferent (<em>P</em> = 0.61) to concentrations up to 280 mg/kg (CV = 13.9 %). For the mature rams, total intake of feed decreased (<em>P</em> = 0.01) from 80.9 ± 3.2 % to 72.3 ± 3.2 %, with respect to increasing concentrations of PTC. Total feed intake duration was less (<em>P</em> ≤ 0.01) when mature rams were offered 330 mg/kg (805.6 ± 440 s) compared with 110 (858.9 ± 44.3 s) and 220 mg/kg (862.9 ± 44.0 s). Although ram lambs consumed total test feed to near entirety, ram lambs took longer (<em>P</em> &lt; 0.01) to consume 280 mg/kg PTC (438.4 ± 26.5 s) compared to control (332.2 ± 27.4 s) pellets. Head bobbing and lip smacking observations increased after mature rams (solution type <span><math><mo>×</mo></math></span> replication, <em>P</em> ≤ 0.01) and ram lambs (solution type, <em>P</em> ≤ 0.01) consumed PTC pellets. The rejection threshold appears to be different for mature rams versus lambs. These results suggest that sheep perceive PTC concentrations between 180 and 280 mg/kg when PTC is incorporated into feed pellets. More research is needed to understand the influence of PTC tasting ability on dietary selection in sheep.</div></div>","PeriodicalId":21758,"journal":{"name":"Small Ruminant Research","volume":"250 ","pages":"Article 107528"},"PeriodicalIF":1.6,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144134581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}