Livestock Science最新文献

{"title":"Effect of feeding strategy on piglet growth and survival and milk production of loose-housed lactating sows","authors":"Signe Emilie Nielsen ,&nbsp;Julie Krogsdahl Bache ,&nbsp;Thomas Sønderby Bruun ,&nbsp;Anja Varmløse Strathe","doi":"10.1016/j.livsci.2025.105668","DOIUrl":"10.1016/j.livsci.2025.105668","url":null,"abstract":"<div><div>The aim of this study was to test how an increased number of daily feedings and different dosing speeds affect piglet growth and survival, sow BW and back fat thickness, and milk production of loose-housed lactating sows. A total of 424 parity 1 to 5 sows were allotted to one of three feeding strategies. All sows were fed the same lactation diets according to the same feeding curves. The control group (Fast3) was fed three times per day, and the entire ration was dosed at one time (high speed) into the trough. In the second group (Slow3), sows were also fed three times per day, but here, the ration was dosed at slow speed doses of 100 g of feed followed by a 60 second pause before feeding the next 100 g dose, resulting in sows standing up for &gt;20 min/feeding. In group three (Slow6), sows were fed six times per day at low speed. A colostrum sample was taken 12 h after farrowing and analyzed for DM, lactose, protein, casein, fat, immunoglobulins, and zinc. After farrowing, litters were standardized to 15 piglets. At standardization, d 6, d17, and at weaning, litter weight, litter size, sow BW and back fat thickness were registered. Milk samples were obtained at d 6 and 17 and analyzed for DM, lactose, protein, casein, fat, and zinc. Feed intake was greater in the Fast3 (7.62 kg/d) sows than in the Slow3 (7.45 kg/d) and Slow6 (7.50 kg/d) sows (<em>P</em> &lt; 0.001). Sows in all three groups had the same litter size at weaning, average milk yield, and average daily litter gain. The composition of colostrum was not affected by feeding strategy. At d 6, the milk content and total daily output of DM, fat, protein, casein, and lactose were unaffected by feeding strategy. There was a higher zinc concentration in the milk of Fast3 sows compared to Slow6 sows (<em>P</em> &lt; 0.05) at d 6 of lactation. The DM, protein, and fat concentrations and total daily output of nutrients were not affected by feeding strategy at d 17. The lactose concentration of the milk at d 17 was lower in Slow3 sows than in Fast3 and Slow6 sows (<em>P</em> &lt; 0.05). The body weight and back fat thickness of sows were similar in all three groups. In conclusion, slower dosing of the feed ration or more daily feedings did not affect piglet survival.</div></div>","PeriodicalId":18152,"journal":{"name":"Livestock Science","volume":"295 ","pages":"Article 105668"},"PeriodicalIF":1.8,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phytase appeared to counterbalance the inimical effect on N balance of acidosis associated with displacing calcium carbonate with calcium chloride in grower pigs","authors":"Hengxiao Zhai ,&nbsp;Estefania Perez-Calvo ,&nbsp;Shikui Wang ,&nbsp;Jingcheng Zhang ,&nbsp;Zhenzhen Wang ,&nbsp;Aaron J. Cowieson","doi":"10.1016/j.livsci.2025.105678","DOIUrl":"10.1016/j.livsci.2025.105678","url":null,"abstract":"<div><div>The objective of this study was to evaluate CaCl₂ as a Ca source by measuring the balance of Ca, Cl, and P, as well as its effects on plasma and urine chemistry. Six experimental diets were arranged in a 3 × 2 factorial design with 3 Ca sources (limestone, CaCl₂, or their 1:1 mixture) and 2 phytase levels (0, and 1,000 FYT/kg). Each diet was fed to 8 individually housed barrows in metabolism cages, totaling 48 pigs for the study. Fecal and urinary samples were collected quantitatively for 5 days following a 5-day adaptation period. Blood samples were collected from the vena cava at the end of the study. The results showed that plasma glucose concentration was significantly higher in pigs fed CaCl₂ than in pigs fed only limestone. Gradually replacing limestone with CaCl₂ tended to increase plasma concentrations of amylase, K, Na, and P. The supplemental phytase significantly increased plasma P concentration but reduced plasma Ca and blood urea nitrogen concentrations. Urinary pH was significantly lower in pigs fed only CaCl₂ compared to other pigs. Phytase supplementation significantly reduced urinary concentration of Ca, and tended to reduce urinary concentration of N and to increase urinary concentration of P. Increasing inclusion of CaCl₂ in place of limestone resulted in stepwise increases in the apparent total tract digestibility and retention of Ca and P. The Cl intake, output through feces and urine, and retention increased stepwise with higher levels of CaCl₂ (<em>P</em> &lt; 0.05). Phytase significantly decreased Ca and P output through feces and increased their retention. There was a decrease in retention of CP in diet including only CaCl₂ compared to other diets without phytase, but an increase in the presence of phytase. In conclusion, the current study shows that CaCl₂ has higher Ca bioavailability than limestone and can reduce urinary pH, potentially reducing emission of NH₃ from slurry. However, the accumulation of Cl in pigs can disrupt the systemic acid-base balance and might cause damage to some organs such as the pancreas. Therefore, CaCl₂ can be used as a Ca source only if its Cl contribution does not endanger dietary electrolyte balance. Additionally, phytase appeared to ameliorate the inimical effect of acidosis associated with CaCl₂ supplementation on N balance.</div></div>","PeriodicalId":18152,"journal":{"name":"Livestock Science","volume":"294 ","pages":"Article 105678"},"PeriodicalIF":1.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563161","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":"Potential of a combined diet containing probiotics and enzymes modulates the performance of fattening goats","authors":"Jiawei Lu ,&nbsp;Zili Chen ,&nbsp;Qin Gao ,&nbsp;Peizhen Li ,&nbsp;Jingang Wang ,&nbsp;Yu Cai ,&nbsp;Zhibo Wang ,&nbsp;Dongxu Li ,&nbsp;Zongyou Wei ,&nbsp;Feng Wang ,&nbsp;Yanli Zhang","doi":"10.1016/j.livsci.2025.105670","DOIUrl":"10.1016/j.livsci.2025.105670","url":null,"abstract":"<div><div>This study aimed at exploring the effects of the probiotic and enzyme administration on nutrient digestibility, rumen morphology, meat quality, and carcass traits in fattening (Yangtse River Delta White) goats. Sixty goats were randomly distributed into three groups, the CON group (a basal diet), the PRO group (a probiotics diet), and the COM group (a combined diet of probiotics and enzymes). The additives amount of <em>B. subtilis, B. licheniformis</em>, and enzymes was 0.06 %, 0.06 %, and 0.02 %, respectively. Probiotics consisted of <em>B. subtilis</em> and <em>B. licheniformis</em>. The composition of compound enzymes was cellulase, β-glucanase, amylase, xylanase, β-mannanase, and protease. Compared with the CON group, the COM group significantly increased the NFC digestibility (<em>P</em> &lt; 0.05) and tended to enlarge the NDF and ADF digestibility (<em>P</em> &lt; 0.10). Rumen morphology manifested that supplementation with probiotics and enzymes predominantly elongated the width of rumen papillae and the thickness of the muscle layer and epithelial cell layer (<em>P</em> &lt; 0.001). Simultaneously, the PRO group and COM group dramatically improved the intensities of b* (yellowness) (<em>P</em> = 0.001) and H* (hue angle) (<em>P</em> &lt; 0.001) in the meat of goats. The combined diet also enriched the carcass traits of goats. Summarily, these results indicate that the combined diet improves nutrient digestibility, meat quality, and carcass traits and modulates the rumen morphology of Yangtse River Delta White goats.</div></div>","PeriodicalId":18152,"journal":{"name":"Livestock Science","volume":"294 ","pages":"Article 105670"},"PeriodicalIF":1.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520800","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":"Detection of anemic sheep using ocular conjunctiva images and deep learning algorithms","authors":"Luara A. Freitas ,&nbsp;Rafael E.P. Ferreira ,&nbsp;Anderson A.C. Alves ,&nbsp;João R.R. Dórea ,&nbsp;Claudia C.P. Paz ,&nbsp;Guilherme J.M. Rosa","doi":"10.1016/j.livsci.2025.105669","DOIUrl":"10.1016/j.livsci.2025.105669","url":null,"abstract":"<div><div>In sheep, severe anemia often results from gastrointestinal nematode infections, commonly caused by <em>Haemonchus contortus</em>, a blood-sucking nematode. The objective of this study was to develop a model to predict packed cell volume (PCV) in sheep through ocular conjunctiva images as a real-time anemia diagnosis approach. The dataset consisted of 3,441 ocular conjunctiva images collected from 392 sheep from three different farms using a smartphone camera. To identify the region of interest in the images (ocular conjunctiva), we annotated 480 images using the Segment Anything Model (SAM). Subsequently, we employed an image segmentation algorithm based on U-net, utilizing the original images and annotations obtained from SAM. We then cropped the segmented images to retain only the ocular conjunctiva region. These cropped and segmented images were used as input data, with PCV as the target variable, in both regression and classification models. We assessed the performance of three different deep neural network (DNN) architectures: VGG19, Inception v3, and Xception. For the classification tasks, a threshold of 27 % (anemic &lt; 27 %, non-anemic ≥ 27 %) was used to convert PCV into a binary variable. The dataset was split into training, validation, and testing sets using random sampling by sheep. The segmentation was evaluated using intersection over union (IoU). To compare the predictive quality in the testing set, we computed the R², Concordance Correlation Coefficient (CCC), and Root Mean Square Error of Prediction (RMSEP) for the regression models, and the accuracy, precision, recall, and <em>F</em>₁ score for the classification tasks. The U-net segmentation model demonstrated reliable segmentation ability, with an average IoU of 0.93, 0.84, and 0.68 in the training, validation, and testing sets, respectively. For regression, the Xception architecture provided the best performance with an R² of 0.24. For the classification models, VGG19 outperformed the other models in classifying individuals as anemic or non-anemic, achieving an <em>F</em>₁ score of 0.62, indicating its moderate ability to distinguish between these two classes. This innovative approach not only expands the possibilities for integrated high-throughput phenotyping through computer vision, but also aids in identifying anemic animals. The results suggest that integrating ocular conjunctiva images with DNN algorithms can contribute to supporting farm-level management decisions, and potentially reduce economic losses due to parasitic infections like <em>H. contortus</em>. Furthermore, this approach not only facilitates real-time anemia diagnosis but also optimizes the use of blood tests, potentially reducing associated costs.</div></div>","PeriodicalId":18152,"journal":{"name":"Livestock Science","volume":"294 ","pages":"Article 105669"},"PeriodicalIF":1.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551896","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":"Performance and feed intake of Nellore steers in extensive, intensive, and integrated pasture-based beef cattle production systems","authors":"Rolando Pasquini Neto ,&nbsp;Althieres José Furtado ,&nbsp;Gabriele Voltareli da Silva ,&nbsp;Annelise Aila Gomes Lobo ,&nbsp;Adibe Luiz Abdalla Filho ,&nbsp;Flavio Perna Junior ,&nbsp;Alexandre Berndt ,&nbsp;Sérgio Raposo de Medeiros ,&nbsp;André de Faria Pedroso ,&nbsp;Patrícia Perondi Anchão de Oliveira ,&nbsp;Paulo Henrique Mazza Rodrigues","doi":"10.1016/j.livsci.2025.105667","DOIUrl":"10.1016/j.livsci.2025.105667","url":null,"abstract":"<div><div>This study evaluated the effects of five pasture-based production systems on the backgrounding-finishing phase performance and feed intake traits of <em>Nellore</em> steers. Over two years (2019–2021), steers (three/year/experimental unit) were randomly assigned to five treatments (with two replicates): 1) degraded pasture without nitrogen (N) fertilization (DP0); 2) silvopastoral with 200 kg N ha⁻¹ (SP200); 3) rainfed pasture with 200 kg N ha⁻¹ (RP200); 4) rainfed pasture with 400 kg N ha⁻¹ (RP400); and 5) irrigated pasture with 600 kg N ha⁻¹ (IP600). Animals grazed exclusively, receiving water and mineral-protein supplement ad libitum. IP600, RP400, and RP200 resulted in the highest Forage and Total Dry Matter Intake (DMI), correlating to superior performance. Supplement DMI was highest in DP0 and lowest in IP600. Considering the seasons, higher stocking rates [expressed in Animal Units (AU) and Equivalents (AE)] were observed in IP600 compared with SP200 (spring and winter), and with RP200, DP0 and SP200 (summer and autumn). Forage allowance and feed efficiency varied seasonally across treatments, influenced by defoliation frequency, intake patterns, and leaf preference during grazing intensity adjustments. During the dry period, performance declined across most treatments due to reduced pasture production, except for IP600, RP400, and RP200, which demonstrated resilience to drought and seasonal variability. Intensified and well-managed systems (IP600, RP400, and RP200) enhanced animal performance and feed intake, suggesting their potential as sustainable pasture management strategies. SP200 and DP0, however, may require tailored management strategies to optimize their benefits.</div></div>","PeriodicalId":18152,"journal":{"name":"Livestock Science","volume":"294 ","pages":"Article 105667"},"PeriodicalIF":1.8,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534312","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":"Effect of benzoic acid supplementation on growth performance and early development of gastrointestinal tract function and immune system in artificially reared suckling piglets","authors":"C.M. Crone,&nbsp;A.P. Rasmussen,&nbsp;C. Larsen,&nbsp;A.R. Williams,&nbsp;M.H. Eskildsen,&nbsp;E.M.H. Christensen,&nbsp;L.V. de Knegt,&nbsp;C. Amdi,&nbsp;J.G. Madsen","doi":"10.1016/j.livsci.2025.105655","DOIUrl":"10.1016/j.livsci.2025.105655","url":null,"abstract":"<div><div>The practice of weaning at 21 to 28 days of age in conventional pig production poses a challenge to the digestive tract of piglets. Post-weaning challenges like diarrhea, small intestinal villous atrophy, and decreased feed intake (FI) are a consequence of the abrupt change in diet from sow milk to solid feed. The aim of this study was to investigate the effect of benzoic acid (BA) to artificially reared suckling piglets on growth performance, intestinal morphology and change in gene expression in the small intestine (SI). Twenty-seven one-day-old piglets were included in this study, and randomly allocated between three dietary groups. All three groups received milk replacer (MR) throughout the entire experimental period. One group only received MR (CON), one was supplemented with liquid creep feed (LCF) (MRLF) from day 10, and one was supplemented with LCF with 0.5% BA (BEN) from day 10. Piglets were euthanized and post-mortem examinations conducted on days 28 and 29 of the experiment. Small intestinal tissue samples were collected for analysis of morphological parameters and gene expression. Results displayed no effect on growth performance, however, the feed conversion ratio was higher (p &lt; 0.05) for MRLF compared to CON in P2 (days 10-28) and higher (p &lt; 0.05) in MRLF and BEN compared to CON P1+P2 (days 1-28). A tendency (<em>p</em> &lt; 0.10) to an increased villus height in the proximal part of the SI and increased (<em>p</em> &lt; 0.05) villus width in the medial part of the SI were observed for BEN, when compared to CON and MRLF. Furthermore, pathways related to the immune system and metabolism were enriched (Adj. <em>p</em> &lt; 0.05) by BEN in comparison to CON and MRLF. In conclusion, BA did show some potential to enhance the intestinal integrity in the pre-weaning period, and thereby developing a more robust piglet during the peri‑weaning period.</div></div>","PeriodicalId":18152,"journal":{"name":"Livestock Science","volume":"294 ","pages":"Article 105655"},"PeriodicalIF":1.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perspectives on the effectiveness of applicable nutritional strategies to mitigate enteric methane over different intensive dairy production system characteristics","authors":"D.W. Olijhoek ,&nbsp;L. Mogensen ,&nbsp;P. Lund ,&nbsp;N.I. Nielsen ,&nbsp;M.R. Weisbjerg ,&nbsp;C.F. Børsting ,&nbsp;T. Kristensen","doi":"10.1016/j.livsci.2025.105666","DOIUrl":"10.1016/j.livsci.2025.105666","url":null,"abstract":"<div><div>A critical evaluation of the applicability of enteric methane mitigation strategies in relation to consistency in effect across types of dairy production systems is warranted before commercial implementation. The aim of this study is therefore to evaluate the effectiveness of selected nutritional enteric methane mitigation strategies in lowering methane emission per kg of energy-corrected (ECM), fat-corrected or fat and protein-corrected milk yield at cow level when considering animal or commercial intensive dairy system characteristics. Hence, the scope is to go beyond a traditional review of mitigation strategies providing perspectives for implementation and identification of gaps in the state-of-the-art knowledge. The evaluated strategies are increased concentrate proportion in the ration, dietary supplementation of linseed or rapeseed as lipid sources, and the dietary additives nitrate and 3-nitrooxypropanol (3-NOP). These strategies are chosen based on a high readiness for implementation and a considerable mitigation potential. A state-of-the-art is given regarding the mode of action, methane reduction potential and persistency, effect on dry matter intake and milk yield, and effects of combinations of mitigation strategies and dietary characteristics. Although scientific evidence is sometimes lacking, variation in the effectiveness of lowering enteric methane emission by mitigation strategies is to be expected across animal characteristics such as breed, life stage, stage of lactation, and production and feeding systems. This evaluation identified that future research should confirm the findings on the persistency over the lactation cycle and in the long-term. Also, effective combinations of mitigation strategies, effects on different breeds and life stages, and suitable mitigation strategies for grazing systems should be studied further.</div></div>","PeriodicalId":18152,"journal":{"name":"Livestock Science","volume":"294 ","pages":"Article 105666"},"PeriodicalIF":1.8,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143478490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ingestive behaviour, performance, and methane emissions of pregnant alpacas grazing cultivated pastures in the high Peruvian Andes","authors":"Laura B. Gualdrón-Duarte ,&nbsp;Cecilia Loza ,&nbsp;José I. Gere ,&nbsp;Nancy F. Huanca-Marca ,&nbsp;Francisco E. Franco ,&nbsp;Yemi Sanca Uscamayta ,&nbsp;Rubén García‐Ticllacuri ,&nbsp;Guadalupe Orellana Ligas ,&nbsp;Diannett Benito López ,&nbsp;Feliciano Rivera Pachiño ,&nbsp;Juan E. Moscoso-Muñoz ,&nbsp;Medardo A. Díaz-Céspedes ,&nbsp;Lizbeth L. Collazos Paucar ,&nbsp;César S. Pinares-Patiño ,&nbsp;Víctor M. Vélez-Marroquín ,&nbsp;Edward H. Cabezas-Garcia","doi":"10.1016/j.livsci.2025.105665","DOIUrl":"10.1016/j.livsci.2025.105665","url":null,"abstract":"<div><div>This study compares grazing patterns, animal performance, and enteric methane emissions (CH₄) of female alpacas (Huacaya and Suri) at two periods of their late pregnancy. Animals were rotationally grazed on a mixed sward at high Peruvian Andes conditions. This study involved two experimental periods (P1 and P2), each lasting 26 days. P1 took place in November 2021, corresponding to the end of dry season (‘Transition period’), whereas P2 was conducted in January 2022, with this coinciding with the beginning of rainy season (‘Wet period’). Forage selectivity was measured using hand plucking of forage harvested, whereas grazing behaviour was recorded by visual observation. Dry matter intake (DMI) was estimated from total faecal collection and <em>in vitro</em> forage digestibility. Fleece characteristics were measured following standard procedures adopted by the local industry. The sulphur hexafluoride (SF₆) gas-tracer technique was used to estimate CH₄ emissions. Data were analysed by a repeated measures model including both alpaca variety and period as fixed effects, whereas alpaca within variety was considered as random. No differences were detected among alpaca varieties either in terms of forage selectivity, grazing behaviour (except for biting rate) or feed intake. Regardless of period, grasses were the main dietary components (≥ 78 %). The proportion of leaves consumed lowered from 84 to 70% and presence of both legumes and herbs increased during P2. Increased nutritional requirements prior to parturition in conjunction with reduced forage quality and DMI (<em>P</em> = 0.004) during P2 led to negative energy and protein balances. This was aligned with increases in fibre growth and diameter, prior to parturition (<em>P</em> ≤ 0.035). Suri displayed faster fibre growth than Huacaya (<em>P</em> = 0.005). Although Huacaya females tended to emit more enteric CH₄ per unit of metabolic live weight than Suri (<em>P</em> = 0.056), this was not reflected either on variety differences in emissions per unit of intake or fleece produced. On average, CH₄ intensity decreased from 0.805 (P1) to 0.530 g/kg clean fleece at P2 (<em>P</em> = 0.032). Results are valuable towards fine-tuning the effect of pregnancy for sustainable alpaca farming.</div></div>","PeriodicalId":18152,"journal":{"name":"Livestock Science","volume":"294 ","pages":"Article 105665"},"PeriodicalIF":1.8,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Are mixed models more effective than linear models in predicting energy utilization for laying hens?","authors":"R.L. Silva ,&nbsp;R. Riveros ,&nbsp;A.K. Almeida ,&nbsp;M. Macari ,&nbsp;B.B. Leme ,&nbsp;N.K. Sakomura","doi":"10.1016/j.livsci.2025.105664","DOIUrl":"10.1016/j.livsci.2025.105664","url":null,"abstract":"<div><div>This study was conducted to develop mathematical models that can overcome the limitations of linear energy partitioning models in laying hens comparing the metabolizable and net energy bases. Three linear models and 2 nonlinear mixed-effect models were fitted to predict the energy utilization efficiency for body tissue deposition and egg production, as well as the maintenance requirements for metabolizable energy (MEm) and net energy (NEm). A total of 30 diets were individually formulated to achieve values below and above the nutritional recommendation of the genetic guidelines. Heat production and energy metabolism were measured in laying hens during the production phase using 6 open-circuit respiration chambers. Diets were randomly assigned into 5 groups, and each diet was replicated 4 times with 6 hens per replication. The experimental protocol included a 5-d adaptation to the experimental diets, 2-d chamber adaptation, 4-d measurements of gas exchange, total excreta collection and growth performance recording under feeding conditions, and 1-d gas exchange measurement under fasting conditions. Feed intake, body weight, egg production, egg mass, and excreta production were measured daily. The variables for total heat production (THP) and fasting heat production (FHP) were obtained through the Brouwer equation using VO₂ and VCO₂ measurements. Apparent metabolizable energy intake (AMEi) was determined by the difference between the gross energy intake and excreted. Retained energy (RE) was determined as the difference between AMEi and THP. Subsequently, the RE was partitioned between RE in body and egg. The RE in egg and body were partitioned into RE as protein and fat. Statistical analyses involved linear regressions and nonlinear mixed-effect regressions of the main variables described. The values obtained for MEm, NEm, and the efficiency of energy retention in body (<em>k</em>_body), and egg (<em>k</em>_egg) in the linear models were 106 kcal/kg^0.75.d, 90 kcal/kg^0.75.d, 0.843, and 0,779, respectively. For nonlinear models the values were 94.15 kcal/kg^0.75.d, 81.72 kcal/kg^0.75.d, 0.463, and 0.638 for MEm, NEm, <em>k</em>_body and <em>k</em>_egg, respectively. Nonlinear models were considered the ideal choice to determine MEm and NEm requirements due to the lowest error. The non-linear mixed model provides a more accurate representation of energy utilization in laying hens compared to linear models, offering a better characterization of energy partitioning within the net energy bases.</div></div>","PeriodicalId":18152,"journal":{"name":"Livestock Science","volume":"294 ","pages":"Article 105664"},"PeriodicalIF":1.8,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465538","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 dietary protein digestion kinetics on sow body condition loss and litter performance during lactation: A meta-analysis","authors":"Hao Ye ,&nbsp;Pieter Langendijk ,&nbsp;Neil W. Jaworski ,&nbsp;Bas Kemp ,&nbsp;Junjun Wang ,&nbsp;Greg Page ,&nbsp;Nicoline M. Soede","doi":"10.1016/j.livsci.2025.105654","DOIUrl":"10.1016/j.livsci.2025.105654","url":null,"abstract":"<div><div>Over the last decades, litter size has increased considerably in modern hybrid sows. This raises concerns over body tissue mobilisation during lactation. Recent evidence suggests that protein tissue mobilization is specifically associated with reduced milk production, affecting litter weight gain, and with impaired ovarian function, affecting sow subsequent reproductive performance. Therefore, efficient utilization of dietary protein for milk production is critical during lactation. A meta-analysis was performed to investigate the role of dietary protein digestion kinetics in lactating sow weight loss, litter weight gain and nitrogen loss to the environment. Data were obtained from 17 peer reviewed publications between 1993 and 2019, including 63 different groups of sows fed with 59 different lactation diets. These publications were selected for their research focus on dietary crude protein concentration in relation to sow body weight loss and litter weight gain during lactation. Percentages of slow, fast and resistant protein in the total protein of the diets were estimated based on previously established <em>in vitro</em> protein degradation characteristics of the used ingredients. Results showed that higher total crude protein reduced sow weight losses and estimated body protein losses during lactation (β = -0.07 kg · (g/kg) ⁻¹, <em>P</em> = 0.01; β = -0.02 kg · (g/kg) ⁻¹, <em>P</em> &lt; 0.01, respectively). An increase in the percentage of slow protein in total protein was associated with decreases of sow total weight loss (β = -1.85 kg/%, <em>P</em> &lt; 0.01), estimated body protein loss (β = -0.33 kg/%, <em>P</em> &lt; 0.01), while the percentage of fast protein in total protein was estimated to increase sow weight loss and estimated body protein loss during lactation (β = 0.46 kg/%, <em>P</em> = 0.03; β = 0.09 kg/%, <em>P</em> = 0.01, respectively). The percentage of resistant protein in total protein did not affect sow body losses but showed a negative relationship with litter weight gain during lactation (β = -0.80 kg/%, <em>P</em> &lt; 0.01). Sow nitrogen loss to the environment during lactation was increased with a higher crude protein in the diet (β = 13.9 g· (g/kg) ⁻¹, <em>P</em> &lt; 0.01), but not affected by protein digestion kinetics. This meta-analysis suggests that a high percentage of slow protein reduces sow body protein mobilization during lactation, probably due to a more sustained and prolonged amino acid delivery to the circulation than with fast protein, and therefore improves utilization of dietary amino acids rather than use them as energy source.</div></div>","PeriodicalId":18152,"journal":{"name":"Livestock Science","volume":"293 ","pages":"Article 105654"},"PeriodicalIF":1.8,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}