Calves are born hypogammaglobulinemic; thus, the newborn calf's immune defense relies on the ingestion and absorption of colostrum, which provides energy, immunoglobulins, immune cells, and cytokines to the newborn calf. A heat treatment applied to colostrum for 60 min at 60°C has been found to be effective at reducing the total bacterial count while preserving the colostrum IgG levels. The objective of this work was to perform a meta-analysis on the association between the characteristics of heat-treated colostrum and the concentration of colostrum IgG, serum IgG concentration, and serum total protein (STP). A meta-analysis was carried out based on existing peer-reviewed literature. Publications comparing colostrum IgG, serum IgG, and STP for heat-treated or raw frozen colostrum were included. The different heating temperatures applied to the colostrum were divided into 2 subgroups: high temperature (HT; >60°C) and low temperature (LT; ≤60°C). Twelve studies, including 21 trials, met the inclusion criteria for colostrum IgG concentration. The results indicated decreases in colostrum IgG by 20.6 g/L [95% confidence interval (CI) = 11.8-29.4] for HT and 5.38 g/L (95% CI = 2.9-7.8) for LT when colostrum was heat-treated compared with raw or frozen colostrum. Heterogeneity was high to moderate (I² = 82% for HT and 65% for LT). The heat treatment of colostrum was also associated with a nonsignificant decrease in serum IgG by 3.40 g/L for HT (95% CI = 7.54-0.74) but a significant increase in serum IgG by 2.65 g/L for LT (95% CI = 1.51-3.79). The regression model indicated that heterogeneity was not explained by any moderators. The heat treatment of colostrum was also associated with a significant increase in STP by 0.21 g/dL for LT (95% CI = 0.07-0.35). In conclusion, the present work demonstrated that the heat treatment of colostrum ≤60°C decreased colostrum IgG by 5.38 g/L for LT and increased serum IgG by 2.65 g/L and STP by 0.21 g/dL. When compared with the range of values observed in the field for serum IgG, the present results are of high interest for the cattle industry. Because immune colostrum benefits also include cytokines and immune cells, further work is required to evaluate the effect of colostrum heat treatment on these 2 immune components of colostrum.

The inclusion of straw in high concentrate total mixed rations (TMRs) of male fattening goats can provide the necessary fiber to prevent ruminal acidosis and maintain growth. The objective of this study was to evaluate the effects of the physical form (PF) of the diet (pelleted vs. conventional) and the straw level (SL) of wheat straw (WS) (15% versus 25%) in total mixed rations on feed intake, growth, total tract digestibility, and blood metabolites of fattening goats. Thirty-two male Beetal goats (27.4 ± 0.28 kg body weight (BW)) were divided randomly into the following four dietary treatments with a 2 × 2 factorial arrangement (n = 8/treatment): (1) CTMR15 (conventional TMR containing 15% WS), (2) CTMR25 (conventional TMR containing 25% WS), (3) PTMR15 (pelleted TMR containing 15% WS), and (4) PTMR25 (pelleted TMR containing 25% WS). Both conventional and pelleted 15% WS TMR had 33.7% neutral detergent fiber (NDF) and 19.3% acid detergent fiber (ADF), whereas in 25% WS TMR the NDF and ADF contents were 38.7% and 22.9%, respectively. The experimental diets were formulated to be iso-nitrogenous (crude protein (CP) = 15%). The dry matter intake (DMI) (1.265 vs. 1.044 kg/day) and average daily gain (ADG) (0.176 vs. 0.143 kg/day) were higher (p < 0.05) in pelleted vs. conventional TMR-fed goats. Irrespective of the PF of the TMR, the 15% WS-fed animals had greater (p < 0.05) DMI (1.206 vs. 1.102 kg/day) and ADG (0.172 vs. 0.144 kg) when compared to those fed on 25% WS diets. Furthermore, feed-to-gain ratio (F:G) was higher (p < 0.05) in the 25% WS-fed goats when compared with the 15% WS-fed animals. Digestibility coefficients, nitrogen balancing, hepatic enzymes, blood metabolites, and hematological parameters were similar (p > 0.05) across all treatments. In conclusion, feeding pelleted TMR with WS improved DMI and growth performance as compared to those fed conventional TMR, and 15% WS performed better than 25% WS without exerting any adverse effects on blood metabolites, liver enzymes, or hematological parameters.

Chromium (Cr) has been reported to modulate blood biochemistry in dairy cows. However, there is a discrepancy in the literature regarding the effects of dietary Cr supplementation on various blood parameters. This meta-analysis aimed to evaluate the effects of Cr supplementation in dairy cows on blood glucose, insulin, glucagon, nonesterified fatty acid (NEFA), cortisol, and serum total protein (STP) concentrations. Following relevant literature data extraction, a 3-level meta-analytical random effect model was fitted to the data expressed as standardized mean difference (SMD) of outcome measures of control vs Cr-supplemented cows (i.e., difference in mean between control and treatment group / pooled standard deviation). The SMD can be categorized as having a small effect = 0.20, a moderate effect = 0.50, and a large effect = 0.80. The meta-regression identified the potential sources of heterogeneity, including the body weight (BW) of cows, experimental duration/duration of Cr supplementation, blood sampling time (3 weeks before parturition till 4 weeks after parturition categorized as the transition period, else as the non-transition period), and form of Cr complexes. Blood glucose did not differ significantly between control and Cr-supplemented cows with an estimated SMD of μ^ = 0.0071 [95% confidence interval (CI): -0.212 to 0.226]. The effect of Cr supplementation on blood insulin was also non-significant with an SMD of μ = 0.0007 (95% CI: -0.191 to 0.193). Cows receiving Cr supplements had significantly higher levels of glucagon than controls (95% CI: 0.116 to 0.489), with an estimated SMD = 0.303. Combined transition and non-transition data suggest Cr supplementation did not impact the concentration of NEFA. However, in transition cows, Cr supplementation significantly decreased blood NEFA levels as compared with controls (95% CI: -0.522 to -0.0039), with estimated SMD = -0.263. The estimated SMD was μ^ = -0.1983 (95% CI: -0.734 to 0.337) for cortisol and -0.0923 (95% CI: -0.316 to 0.131) for total protein. In summary, Cr supplementation in the transition cows decreased NEFA concentration. Blood glucose, insulin, cortisol, and STP concentrations were unaffected. However, Cr supplementation increased glucagon concentration.

Introduction: Distiller’s dried grains with solubles (DDGS), a by-product of grain fermentation for ethanol production, are extensively used in livestock feed. Given their nutrient composition, DDGS could potentially influence methane (CH₄) emissions, a significant greenhouse gas concern in ruminant production systems. This study utilized a multilevel random-effects meta-analysis to assess the impact of DDGS inclusion in cattle diets on CH₄ production and yield.Methods: The literature search was conducted on 23 July 2024. Studies reporting CH₄ emissions and dry matter intake (DMI) in cattle fed DDGS-based diets were identified, and data extraction was performed. The meta-analysis calculated the mean difference (MD) for DMI and CH₄ yield and the relative mean difference (RMD) for CH₄ production across the selected studies.Results: A total of k = 25 effect sizes from 10 studies were included in the DMI meta-analysis. DDGS had no significant effect on DMI in dairy or beef cattle (p = 0.770, MD = 0.070, 95% confidence interval [CI] from −0.420 to 0.561). For CH₄ production, k = 24 effect sizes from 10 studies were analyzed, revealing no significant effect (p = 0.759, RMD = −1.045, 95% CI: from −8.025 to 5.935). Similarly, the meta-regression model indicated that the diet’s ether extract (EE) had no significant influence (p = 0.815, 95% CI from −1.121 to 1.409) on CH₄ production. For CH₄ yield, k = 23 effect sizes from 10 studies were included, with results showing no significant effect (p = 0.475, MD = −0.434 g/kg DMI, 95% CI: from −1.673 to 0.805). The regression model for the EE content of the diet also showed no significant impact on CH₄ yield (p = 0.311, 95% CI: from −0.366 to 0.122).Discussion: The findings suggest that the inclusion of DDGS does not significantly affect DMI, enteric CH₄ production, or CH₄ yield in cattle. Moreover, the EE content in DDGS-containing diets does not significantly influence CH₄ outcomes. These results indicate that DDGS can be incorporated into cattle diets without exacerbating CH₄ emissions, contributing to sustainable livestock feeding practices.

This study investigates the effect of altitude on the fatty acid composition of pasture grass, yak milk, and yak ghee on the Qinghai–Tibet Plateau, aiming to understand how environmental factors influence the nutritional quality of these products. Samples were collected from four different altitudes and analyzed for fatty acid profiles using gas chromatography. The analysis reveals that higher altitudes are associated with an increased prevalence of beneficial unsaturated fatty acids, such as oleic acid (C18:1) and linoleic acid (C18:2n6c). These findings highlight the significant influence of altitude on yak lipid metabolism, ultimately enhancing the nutritional value of dairy products. This adaptation not only supports the health and resilience of yaks, but also provides vital nutritional benefits to residents in high-altitude regions. The research underscores the importance of further investigations to optimize dairy production practices, ensuring improved food security and health outcomes for residents of the plateau.