Journal of Dairy Science最新文献

{"title":"Canonical prolactin signaling and global mRNA expression in the skin of Holstein heifers carrying the SLICK1 allele of the prolactin receptor gene.","authors":"Montana D Altman, Alice T Mathews, Maria B Rabaglino, Russell C Hovey, Anna C Denicol","doi":"10.3168/jds.2024-25821","DOIUrl":"https://doi.org/10.3168/jds.2024-25821","url":null,"abstract":"<p><p>The SLICK1 allele of the prolactin receptor gene (SLICK1) is associated with a short hair coat and thermotolerance in cattle. SLICK1 includes a single base pair deletion that creates a premature stop codon and prevents transcription of 120 amino acids involved in JAK/STAT signaling. It is unknown if SLICK1 modifies JAK/STAT signaling or the transcriptional response to prolactin. To investigate PRLR-associated signaling pathways in heterozygous SLICK1+/- Holsteins (slick), we performed immunohistochemistry on skin explants obtained from slick (n = 5) and non-slick (n = 6) heifers to evaluate phosphorylated (p)STAT1, pSTAT3, and pSTAT5 immunoreactivity (pSTAT1+, pSTAT3+, pSTAT5+) in hair follicles (HF) and sweat glands (SG). In slick skin, more HF lacked pSTAT3 immunoreactivity compared with non-slick skin. No difference was found for the proportion of pSTAT1+ or pSTAT5+ HF, nor the proportion of pSTAT1+ and pSTAT3+ SG between genotypes. Within immunoreactive HF and SG, there were no differences between genotypes in the proportion of pSTAT1+, pSTAT3+, or pSTAT5+ cells in HF, or pSTAT1+ and pSTAT3+ cells in SG. Next, we investigated pSTAT3 immunoreactivity and the transcriptome of slick and non-slick skin explants after exposure to a controlled level of prolactin in vitro. Skin explants from slick (n = 6) and non-slick (n = 6) heifers were cultured for 36 h in the presence of 50 ng/mL recombinant ovine prolactin, bisected, and each half underwent immunohistochemistry for pSTAT3 or RNA sequencing. No difference was found between genotypes in the proportion of pSTAT3+ HF or SG, nor the proportion of pSTAT3+ cells within HF or SG. RNA was poly-A enriched and sequenced using Novaseq6000 (Illumina) and 221,342,181 reads were mapped to the bovine genome (bosTau 9). The DESeq package was used to determine the differentially expressed genes (DEG) with P < 0.01 and fold-change > 1.5. There were 87 upregulated and 79 downregulated DEG in slick compared with non-slick skin. Ingenuity Pathway Analysis identified IL-17, leukocyte extravasation, and wound healing as upregulated signaling pathways, as well as activation of TNF, IL-1β, OSM, IFNγ, IL-17α, and IL-1R and inhibition of SHH and BMP4 upstream of the DEG. Analysis of genomic regions within ± 2 kb of all DEG's respective transcription start sites revealed enrichment of 3 binding sites for the OCT1 transcription factor in slick skin. In conclusion, our results suggest differences in local immune regulation, hair growth inhibition, and tissue remodeling in slick skin.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of glutathione S-transferase mu 2 in mitigating fatty acid-induced hepatic inflammation in dairy cows.","authors":"Jinxia Li, Chenchen Zhao, Dandan Qi, Fanrong Kong, Menglin Liu, Jie Gao, Enzhu Li, Wenwen Gao, Xiliang Du, Yuxiang Song, Guowen Liu, Xinwei Li, Haihua Feng, Lin Lei","doi":"10.3168/jds.2024-25740","DOIUrl":"https://doi.org/10.3168/jds.2024-25740","url":null,"abstract":"<p><p>Fatty liver is a major metabolic disorder in perinatal dairy cows, characterized by elevated plasma concentrations of nonesterified fatty acids (NEFA) and hepatic inflammation. Glutathione S-transferase mu 2 (GSTM2), a phase II detoxification enzyme, regulates cellular antioxidant and detoxification processes in nonruminants. However, its involvement in NEFA-induced hepatic inflammation in dairy cows with fatty liver remains unclear. This study aimed to elucidate the role of GSTM2 in mediating hepatic inflammation caused by elevated NEFA levels in dairy cows with severe fatty liver. An in vivo study was conducted using 10 healthy cows (hepatic triglyceride [TG] content <1%) and 10 cows with severe fatty liver (hepatic TG content >10%), matched for the number of lactations (median = 3, range = 2-4) and DIM (median = 9 d, range = 3-15 d). Liver tissue and blood samples were collected before feeding. Compared with healthy cows, cows with severe fatty liver had higher plasma concentrations of NEFA, BHB, haptoglobin (HP), plasma amyloid A (SAA), and lower plasma concentration of glucose. These cows also showed significantly lower abundance of hepatic GSTM2 and overactivated hepatic inflammatory pathways, as indicated by increased abundance of phosphorylated inhibitor of κB (IκB)α and nuclear factor κB (NF-κB) p65, NLR family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein containing CARD (ASC), and caspase-1 (CASP1), as well as mRNA levels of tumor necrosis factor α (TNFA), IL6, and IL1B. In vitro, hepatocytes isolated from 5 healthy calves (1 d old, fasted female, 30-40 kg of BW) were used to determine the effects of GSTM2 on hepatic inflammation. First, hepatocytes were treated with NEFA (1.2 mM) for varying durations (0.5, 1, 3, 6, 9, 12, 15, or 18 h). The NEFA treatment significantly increased the phosphorylation of IκBα and NF-κB p65, protein abundance of NLRP3, ASC and CASP1, and mRNA levels of TNFA, IL6 and IL1B, peaking at 9 and 12 h. Second, hepatocytes were treated with different concentrations of NEFA (0, 0.6, 1.2, or 2.4 mM) for 9 h, which decreased GSTM2 protein and mRNA abundance. Meanwhile, GSTM2 was silenced using small interfering RNA or overexpressed using adenovirus for 48 h in hepatocytes, followed by NEFA treatment. Silencing GSTM2 augmented the NEFA-induced increase in phosphorylation of IκBα and NF-κB p65, as well as protein abundance of NLRP3, ASC and CASP1, and mRNA levels of TNFA, IL6 and IL1B. Conversely, overexpression of GSTM2 mitigated these inflammatory signals upon NEFA treatment. In summary, these findings indicate that GSTM2 plays a crucial role in modulating NEFA-induced hepatic inflammation. Targeting GSTM2 may offer new strategies to treat or prevent fatty liver disease in dairy cows.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combining High Pressure Processing and Low Storage Temperature to Extend the Functionality Shelf Life of Low-Moisture Part-Skim Mozzarella Cheese.","authors":"L A Jiménez-Maroto, S Govindasamy-Lucey, J J Jaeggi, M E Johnson, J A Lucey","doi":"10.3168/jds.2024-26112","DOIUrl":"https://doi.org/10.3168/jds.2024-26112","url":null,"abstract":"<p><p>High pressure processing (HPP) and low temperature storage (0°C) were explored as alternatives to freezing for extending the performance shelf life of low-moisture part-skim (LMPS) Mozzarella intended for export. Batches (n = 5) of reduced Na LMPS Mozzarella were manufactured using camel chymosin as a lower proteolytic type of rennet. Cheeses were stored for 2 wk at 4°C, divided into control (non-HPP) and HPP (600 MPa for 3 min) groups, and stored at 3 different temperatures (4, 0, and -18°C) for 365 d. Analyses were performed at 0, 90, 150, 210, 270, and 365 d of storage. Frozen and 0°C samples (∼2.3 kg) were thawed/tempered at 4°C for 1 wk before analysis. Urea-PAGE and quantification of the pH 4.6 soluble N over time were used to monitor primary proteolysis. Body and rheological properties were monitored using texture profile analysis (TPA) and dynamic low-amplitude oscillatory rheology. Changes in flavor, body, shred properties, and pizza performance were evaluated using quantitative descriptive analysis with 12 trained panelists using a 15-point scale. HPP treatment caused ∼5 log cfu/ml reduction in starter counts, partial solubilization of the insoluble Ca, and a small pH increase (from ∼5.2 to 5.3). The rate of primary proteolysis was reduced by HPP and low temperature storage. HPP treatment reduced initial cheese hardness, but no further significant decrease was observed over storage time, while the hardness of non-HPP samples decreased over the 365 d of storage, apart from the frozen samples. In pizza applications, blister quantity development and loss of strand thickness were limited by storage at -18°C. Freezing LMPS Mozzarella to -18°C gave the least changes in proteolysis and pizza performance over the 365 d of study, storage of cheese at 0°C slowed the loss of hardness and the deterioration of pizza performance attributes. The combination of HPP and 0°C storage of cheese resulted in little change in blistering quantity of pizza during the 365 d of study, whereas cheese stored at 0°C had blisters covering much of the pizza after this extended storage time. Combining HPP with low temperature storage is a promising alternative approach to freezing for the extension of the functionality shelf life of LMPS Mozzarella.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 clove (Syzygium aromaticum) extract on antibacterial activity, phytochemical properties, and storage quality of flavored milk beverages.","authors":"Maha M Bikheet, Hanaa M Hassan, Maha O A Omar, Waled M Abdel-Aleem, Salma M Galal, Sameh A Korma, Salam A Ibrahim, Khaled S Nassar","doi":"10.3168/jds.2024-26023","DOIUrl":"https://doi.org/10.3168/jds.2024-26023","url":null,"abstract":"<p><p>The antibacterial efficacy of clove extracts (Syzygium aromaticum) prepared using 80% ethanol and water against pathogenic bacteria was evaluated, along with the development of a novel antimicrobial milk beverage incorporating these extracts. Seven flavored milk beverage (FMB) treatments were prepared: a control and 6 with clove extracts at 0.5%, 0.7%, and 1% for each solvent. The effects on physicochemical, phytochemical, antioxidant, microbiological, color, and sensory properties were assessed over 15 d of storage at 4 ± 1°C. The ethanolic clove extract exhibited significantly higher antimicrobial activity against Staphylococcus aureus, Listeria monocytogenes, E. coli O157, Salmonella typhi, and Klebsiella pneumoniae, with inhibition zone diameters of 20 mm, 21 mm, 20 mm, 19 mm, and 20 mm, respectively, compared with the aqueous extract. On d 0, the sample of 1% ethanolic clove extract (FMB3) showed the highest proximate analysis values, including TS (22.41%), protein (4.61%), fat (4.58%), ash (0.97%), and gross energy (108.65 Kcal). It also showed the highest pH (6.7), flavor score (19.20), texture score (9), and overall acceptability score (39.50) and the lowest carbohydrate content (12.27%), lightness value (69.60), and yellowness value (97.47). Over the 15-d storage period, the total phenolic content (TPC), total flavonoid content (TFC), and total antioxidant capacity (TAC) increased, with the FMB3 sample exhibiting the highest TPC (58.70 mg/100 g), TFC (46.15 mg/100 g), and TAC (487.10 mg/100 g). All beverages remained free from yeasts and molds, and FMB3 exhibited the lowest bacterial count (5.13 log cfu/mL). The results indicate that ethanolic clove extract effectively inhibits spoilage and pathogenic organisms and enhances the sensory and functional properties of FMB. This finding offers a promising approach for improving the quality and safety of dairy products.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"International Symposium on Ruminant Physiology: Integrating our understanding of stress physiology.","authors":"E A Horst, E J Mayorga, L H Baumgard","doi":"10.3168/jds.2024-25794","DOIUrl":"https://doi.org/10.3168/jds.2024-25794","url":null,"abstract":"<p><p>Abiotic stressors reduce farm animal productivity, and one of the most globally studied is heat stress (HS) because it compromises almost every profitability metric. Surprisingly, the biological consequences of seemingly very different stressors are highly conserved. Thus, although this review focuses on the broad impact of stress, describing the biology and etiology of how HS alters farm animal productivity provides the conceptual foundation for how all stressors can become pathological. Suboptimal production during HS was traditionally thought to result from hypophagia. However, independent of feed intake, HS affects a plethora of endocrine, physiological, metabolic, circulatory, and immunological variables. It is becoming increasingly clear that these changes are chronologically causal and that the etiological epicenter is a compromised gastrointestinal tract (GIT) barrier. A hyperpermeable GIT allows luminal contents to infiltrate, and these antigens stimulate an immune response with local and systemic inflammatory implications. Once activated, most leukocytes switch from oxidative phosphorylation to aerobic glycolysis and increase their glucose utilization. The glucose requirement of an intensely triggered immune system can exceed 2 kg/d in a lactating dairy cow. Whole-body metabolic adjustments are coordinated to ensure glucose is prioritized for the immune system and this is primarily characterized by increased basal and stimulated circulating insulin, hypercortisolemia, and hyperprolactinemia. This hormonal profile is accompanied by decreased adipose tissue mobilization and skeletal muscle insulin resistance. Interestingly, the aforementioned physiology is almost identical to distinctly different abiotic and biotic stressors. For example, feed restriction, weaning, cold stress, and noise stress all have a similar metabolic and inflammatory footprint, and this physiology can be closely recapitulated by experimentally-induced immune activation. Ultimately, these stressors are \"psychological\" and emanate their pathology from a compromised GIT barrier. Stress negatively affects GIT epithelia via at least 2 mechanisms: (1) mast cell degranulation and (2) immune cell creation of an apical pro-oxidant environment that paradoxically favors pathogen colonization. The metabolic, physiological, and immunological consequences of stress are highly conserved, and these analogous responses are symmetrical because the GIT is seemingly ground zero for all of them.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sources of variation underlying the production of lactose by dairy cows.","authors":"J I Gargiulo, S C Garcia, R C Hovey","doi":"10.3168/jds.2024-25644","DOIUrl":"https://doi.org/10.3168/jds.2024-25644","url":null,"abstract":"<p><p>This study explored variability in the production of lactose by dairy cows, and the factors underlying it, using herd testing data from New South Wales, Australia. The dataset spanned 14 years (2008-2022) and comprised 393,772 records from 33,280 cows across 85 herds, alongside meteorological data and dairy sire genetic data. Variables included milk yield, composition, and quality; reproductive data; breed information; and environmental factors. We found significant variation in lactose yield (LY), lactose percentage (LP), and milk solids yield (MSY) across breed, parity, and stage of lactation. Holsteins had the highest LY and MSY and the lowest LP, whereas Jerseys produced more MSY per unit of LY (MSY:LY ratio). We observed a negative correlation between LY and milk composition variables (fat and protein percentages) and environmental factors such as the temperature-humidity index. Heritability estimates indicated a moderate genetic influence on LY, LP, and MSY:LY (0.24-0.33). The identification of cows producing milk with a consistently lower LP or higher MSY:LY ratio highlights the potential for selective breeding against lactose output to increase the production of milk components and suppress milk volume. These findings highlight the potential to modulate lactose synthesis that could enhance the milk production efficiency of dairy cows, and potentially reduce their environmental impact.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Technical factors affecting estimation of nitrogen balance of dairy cattle in climate respiration chambers.","authors":"K Nichols, S J J Alferink, T Zandstra, M J W Heetkamp, J Dijkstra","doi":"10.3168/jds.2024-25901","DOIUrl":"https://doi.org/10.3168/jds.2024-25901","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Nitrogen retention is often overestimated when calculating N balance of dairy cattle. This study determined if different N analysis methods [Kjeldahl (KJEL) or elemental analysis (EA)] and sample collection and storage protocols when using climate respiration chambers (CRC) affected the estimation of N intake, milk N secretion, manure N excretion, volatile N appearance, and N retention. Twenty-eight Holstein-Friesian cows were housed in CRC for a 4-d measurement period. Nitrogen intake was estimated using individual forages (corn silage and grass silage) and mixtures of forages sampled before or after storage at 4°C. Total N content of forages was the sum of NH&lt;sub&gt;3&lt;/sub&gt;-N content in wet samples and N content in dry samples analyzed by KJEL and EA. Nitrogen content in dry concentrate samples was analyzed by KJEL and EA. Secretion of N in milk was based on N content in wet samples analyzed by KJEL and EA. Manure N excretion was based on the N content of wet manure samples with and without acid preservative analyzed by KJEL and EA. Volatile N consisted of N in condensed water from the CRC heat exchanger analyzed by KJEL, and aerial N. Aerial N was determined using an NH&lt;sub&gt;3&lt;/sub&gt; sensor or acid trap analyzed by KJEL. Volatile N was quantified during the 4-d measurement period (cow phase), CRC cleaning (cleaning phase), and between CRC cleaning and the next 4-d measurement period (post-cleaning phase). Nitrogen content, with and without accounting for NH&lt;sub&gt;3&lt;/sub&gt;-N, was higher in dry silage samples when analyzed using EA compared with KJEL. Nitrogen intake was higher when forages were analyzed by EA but was not affected by forage source (individual forages or forage mixtures pre- or post-storage) or interaction between forage source and N analysis method. Nitrogen analysis method did not affect the N content of milk or manure. Acid addition to manure samples did not affect N content on a wet basis but tended to increase the DM content of manure such that N content on a DM basis was lower in acid-preserved samples. There was no effect of aerial N analysis method (acid trap or NH&lt;sub&gt;3&lt;/sub&gt; analyzer) and no interaction between volatile N measurement phase and N analysis method on volatile N appearance. Nitrogen retention was lower when samples were analyzed using KJEL compared with EA (19 and 36 g/d, respectively), attributed to the lower N content of forages when analyzed with KJEL. The measurement phase used for estimating volatile N production did not affect N retention. Overall, N analysis method of forages impacts the estimation of N intake but may be less important for milk and manure in terms of the impact on N retention. When using CRC to quantify volatile N, an acid trap or NH&lt;sub&gt;3&lt;/sub&gt; analyzer for aerial N can be used with similar outcomes. Although N analysis by KJEL resulted in lower N retention relative to EA, this may be artificial if KJEL underestimates N content of forages. Overestimation of N retention was not mitigat","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 pH adjustments on a novel micellar casein-based edible 3D printing formulation.","authors":"Michael J McAnulty, Benjamin M Plumier, Amanda L Miller, Peggy M Tomasula","doi":"10.3168/jds.2024-25768","DOIUrl":"https://doi.org/10.3168/jds.2024-25768","url":null,"abstract":"<p><p>Three-dimensional (3D) food printing holds the potential to help reduce food waste by precise portion control and use of materials that are produced in excess or are otherwise discarded. This relatively new technology is likely to undergo decreases in equipment costs. To take advantage of such prospects, we developed a novel micellar casein-based edible 3D printing formulation. Our formulation relies on a highly concentrated micellar casein solution (27.75%, wt/wt, final) along with pH adjustments (3.5, 4.0, 4.8, 6.7, 7.2, and 8.2) at chilled temperature (4-9°C) to avoid premature aggregation. In comparison to the natural pH of 6.7, both alkalinization and acidification past the isoelectric point of 4.6 enhanced both elastic and viscous moduli that enable for shape retention during and after extrusion from a 3D food printer. However, alkalinization led to smaller increases in the viscous modulus and did not lead to the shape retention that acidification to 4.0 or 3.5 does. Both acidification and alkalinization also resulted in rougher surface textures compared with the formulation at pH 6.7. Whereas the pH 4.8 formulation had inferior shape retention qualities compared with those at the other pH values tested, it had optimized water resilience, defined here as minimized swelling and dissolution of dried structures placed in water. Overall, we present a novel casein-based 3D printing formulation that could be printed while chilled, and with properties that could be modified by pH adjustments.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 preweaning calf daily gain and feed intake on first-lactation performance: A metaanalysis.","authors":"Wen Jiang, Jingjun Wang, Shangru Li, Shuai Liu, Yimin Zhuang, Shengli Li, Wei Wang, Yajing Wang, Hongjian Yang, Wei Shao, Zhijun Cao","doi":"10.3168/jds.2024-25742","DOIUrl":"https://doi.org/10.3168/jds.2024-25742","url":null,"abstract":"<p><p>This study aimed to investigate the effects of daily weight gain and feed intake of calves on first-lactation milk yield and composition using a metaanalysis. A total of 57 treatments from 18 studies were included in the study. Univariate and multivariate mixed models were constructed for calf ADG, liquid DMI (LDMI), starter DMI (SDMI), 305-d milk, milk fat, and protein yields data to gain insight into the effects of preweaning calf daily gain and feed intake on first-lactation performance. Univariate mixed models revealed ADG was significantly positively correlated with 305-d milk, milk fat, and protein yields during the first-lactation period. This indicates that ADG is a significant determinant of enhanced production performance during the first-lactation period. Furthermore, a significant quadratic correlation was observed between LDMI and 305-d milk, milk fat, and protein yields during the first-lactation period. The optimal performance during the first lactation was achieved when LDMI was maintained at 0.79 to 0.80 kg/d. In contrast, no significant association was observed between SDMI and production performance during the first-lactation period. Further multivariate mixed model analyses demonstrated that, when the effects of the 3 independent variables were considered collectively, only ADG exhibited a significant positive effect on 305-d milk yield and fat production during the first-lactation period. However, the modeling of milk protein yield revealed that ADG and LDMI exerted a significant influence, whereas the effect of SDMI remained insignificant. This study emphasized the significant effect of ADG and LDMI in optimizing the future lactation performance of calves, providing a crucial foundation for the development of scientific feeding management strategies.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing milk urea nitrogen as an indicator of protein nutrition and nitrogen utilization efficiency: A meta-analysis.","authors":"Xiaowei Zhao, Changjiang Zang, Shengguo Zhao, Nan Zheng, Yangdong Zhang, Jiaqi Wang","doi":"10.3168/jds.2024-25656","DOIUrl":"https://doi.org/10.3168/jds.2024-25656","url":null,"abstract":"<p><p>This meta-analysis aimed to assess the effectiveness of MUN as a tool for evaluating protein feeding and nitrogen (N) use efficiency in dairy cows. In this study, we selected 48 research papers published between January 2004 and April 2024, focusing on studies involving Holstein dairy cows with detailed dietary descriptions and results, including MUN, milk protein percentage, and yield, and dietary data on CP and NFC. We employed generalized linear fixed or mixed-effects models for data analysis, utilizing forest plots to visualize the estimated effects. On average, the cows included in the study were 121 DIM, produced 34.8 kg/d of milk, with milk protein at 3.16% and milk fat at 3.69%. The average MUN levels were 12.5 mg/dL, with urine N and fecal N excretions of 193 g/d and 196 g/d, respectively. The average DMI was 23.2 kg/d, with an N intake of 596 g/d. The dietary composition averaged 16.0% CP, 43.0% NFC, 33.6% NDF, 20.9% ADF, and 1.64 Mcal/kg of NEL. Our analysis revealed a close association among dietary NFC, CP, and MUN concentrations, identifying NFC and CP as key factors affecting MUN levels. When MUN levels ranged from 8 to 16 mg/dL, the dietary NFC/CP ratio was typically between 2.15 and 3.60. Furthermore, MUN exhibited a weak positive correlation with milk yield, milk protein percentage, and milk protein yield, a strong positive correlation with urine N excretion, and a negative correlation with the ratio of milk N to intake N. These findings imply that the dietary NFC/CP ratio significantly affects the MUN concentration. Further, it seems probable that by monitoring MUN, NFC, and CP levels together, dairy producers can achieve better balance of NFC and CP in diets, thereby enabling optimization of feed formulation and enhancement of the management of dairy cows.</p>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}