Effects of fresh-cow grouping strategy and rumen-protected glucose on production performance, reproductive variables and risk of culling in Holstein cows.

BACKGROUND: The interaction effects of duration of stay in fresh-cow diet and supplementation with rumen-protected glucose (RPG) on productivity of dairy cows are largely unknown. We hypothesised that a faster transition from fresh-cow diet (higher forage:concentrate) to lactation-cow diet (lower forage:concentrate), combined with supplementation of fresh-cow diet with RPG will have positive effects on production and health of dairy cows. OBJECTIVES: To investigate the immediate and long-term effects of length of stay in fresh-cow diet and supplementation with RPG on productive and reproductive performance of high-producing dairy cows. METHODS: A total of 264 multiparous Holstein cows (average parity ± standard deviation = 3.2 ± 1.3, ranging from 2 to 6) were used in a 2 × 2 factorially arranged trial. Treatments were the feeding duration of a fresh-cow diet for 14 or 21 days, each combined by daily supplementation of the fresh-cow diet with ground corn grain or RPG product top dressed at 500 g/day/head. RESULTS: The earlier transition from fresh-cow to lactation diet resulted in greater milk production from 15 through 21 days in milk (DIM; by 2.28 kg/day), and also fat-corrected milk production on 30 and 60 DIM, respectively. Corn grain or RPG supplementation did not affect the average milk production (1 to 21 DIM), as well as milk production and composition on 30 and 60 DIM. Although extent of body condition loss at transition tended to be lesser in cows switching faster to lactation diet, these cows lost more body condition from 30 to 90 DIM. Survival analysis on calving-to-conception interval and time to removal from herd did not find any significant difference across treatments. CONCLUSIONS: The positive effects of earlier transition from fresh-cow to lactation diet were evident by greater milk production from 15 through 21 DIM, and fat-corrected milk production (30 and 60 DIM), at the expense of body condition in high-producing dairy cows. A daily topdress of RPG on fresh-cow diet had no immediate or carryover effects on production of dairy cows.

RNA-Seq based genetic variant discovery provides new insights into controlling fat deposition in the tail of sheep.

Genetic basis of fat deposition in sheep tail have not been completely elucidated yet. Understanding the genetic mechanisms controlling fat-tail size can improve breeding strategies to modulate fat deposition. RNA sequencing has made it possible to discover genetic variants that may underlie various phenotypic differences. Hence, to identify genetic variants that are important for describing different fat-tail phenotypes in sheep, RNA sequencing was used for single nucleotide polymorphism (SNP) calling in two Iranian sheep breeds (Lori-Bakhtiari, fat-tailed; n = 4, vs Zel, thin-tailed; n = 4). Using a stringent pipeline, a total of 112,344 known SNPs were genotyped, of which 30,550 and 42,906 SNPs were shared by at least two Lori-Bakhtiari and Zel, respectively. Comparing these SNPs showed 2,774 (including 209 missense and 25 deleterious SNPs) and 10,470 (including 1,054 missense and 116 deleterious SNPs) breed-specific SNPs in Lori-Bakhtiari and Zel sheep, respectively. Potential breed-specific SNPs were detected by considering those located in QTL regions associated with fatness or reported as important candidates in previous similar studies. Of the breed-specific SNPs, 724 and 2,905 were located in the QTL regions. Functional enrichment analysis of the affected genes revealed several enriched gene ontologies and KEGG pathways related to fat metabolism. Based on the results, several affected genes were proposed to be strongly linked with fat deposition such as DGAT2, ACSL1, ACACA, ADIPOQ, ACLY, FASN, CPT2, SCD, ADCY6, PER3, CSF1R, SLC22A4, GFPT1, CDS2, BMP6, ACSS2, ELOVL6, HOXA10 and FABP4. Moreover, several SNPs were found in the candidate genes related to fatty acid oxidation introducing them as promising candidates responsible for lower fat content in tail of Zel. Our findings provided new insights into the genetic mechanisms of fat deposition in sheep, which can serve to designing appropriate breeding programs.

Effects of reducing crude protein concentration in starter feed containing constant rumen undegradable protein on dairy calves performance.

This study aimed at investigating the effects of decreasing crude protein (CP) in diets with constant rumen undegradable protein (RUP) content on dry matter (DM) intake, growth, feed efficiency (FE) and blood parameters in calves in a randomized complete block design. Dietary treatments included: (a) a calf starter containing 200 g/kg CP (62 g/kg RUP, based on DM), (b) a starter containing 180 g/kg CP (65 g/kg RUP, based on DM) and (c) a starter containing 160 g/kg CP (65 g/kg RUP, based on DM). A total 42 newborn male and female Holstein calves were fed 8 L milk/day until day 45, after which they were weaned and continued the experiment until day 75. Solid feed intake and total DM intake were measured daily, and body weight and skeletal growth parameters including withers height and heart girth were recorded weekly. Blood samples were collected on days 45 and 75. Solid feed intake, total DM intake, weaning weight, average daily gain from birth to weaning and from birth to 75 days, final weight and FE were not affected by the experimental treatments. In addition, skeletal growth parameters were similar among groups. Glucose concentration was similar among treatments; however, calves fed the starter containing 160 g/kg CP had significantly lower plasma concentrations of albumin and urea nitrogen compared with those fed starters containing 180 and 200 g/kg CP. These results indicate that CP level in the calf starter could be decreased to 160 g/kg DM if RUP levels stay at 65 g/kg DM, without negatively affecting feed intake and calf performance.

A meta-analysis and meta-regression of the effects of vitamin E supplementation on serum enrichment, udder health, milk yield, and reproductive performance of transition cows.

Vitamin E is an essential nutrient for cows, but the effect of vitamin E supplementation is often controversially discussed in the published literature. The main goal of this meta-analysis was to evaluate the effects of vitamin E supplementation on its serum and colostrum enrichment, milk yield (MY), and somatic cell counts (SCC), as well as on various reproductive variables of transition cows, by considering a large set of variables that might influence the responses to vitamin E supplementation. After a broad search in journals and databases with keywords related to transition cows supplemented with vitamin E and appropriate filtering of the results, 36 papers including 53 trials were selected, and their data were extracted into a database. A meta-analysis was conducted on the extracted data. The analysis showed enrichment of serum vitamin E both at parturition (effect size: 2.423) and postpartum (effect size: 0.473), but no effects of vitamin E supplementation on IgG concentration in colostrum (effect size: -0.05) were found. There was a tendency for supplemented cows to produce more milk (effect size: 1.29) during the first month of lactation. Because of large heterogeneity, a meta-regression was performed but none of the presumed influencing factors was identified as a potential variable affecting MY. Milk SCC, as an indicator of udder health, was unaffected by vitamin E supplementation. Vitamin E supplementation tended to decrease the calving to first estrus period (CFP), whereby supplementing Se and taking parity into account in the analysis significantly lowered the CFP. Cows receiving additional vitamin E had, on average, 6.1% fewer cases of retained placenta, whereby Se supplementation and breed were key factors improving the effect of vitamin E to reduce retained placenta. In this regard, breeds other than Holstein responded better and these cows showed a lower incidence of retained placenta. The supplemented cows showed fewer days open (effect size: -0.31), and this improvement was affected linearly by increasing the dosage administered. Also, cows showed fewer services per conception with increasing dosage of vitamin E. In conclusion, this analysis showed that supplementing vitamin E did not affect SCC or colostrum quality but improved reproductive performance of transition cows, an effect consistent with increased levels of serum vitamin E and, for some variables, being modulated by Se supplementation.

Maternal supplementation with fish oil modulates inflammation-related MicroRNAs and genes in suckling lambs.

Dietary n-3 long-chain fatty acids (n-3 LCFA) have been shown to modify lipid metabolism and immune function. The objective of this study was to evaluate the effect of periparturient fish oil (FO) supplementation on the inflammation and metabolic health of ewes and their lambs at a molecular level. Prepartum ewes were fed control diet (CON, n = 12) or CON supplemented with 2% DM of calcium soap of FO (n = 12) from 28 days before until 21 days after parturition. The ewes were evaluated for plasma metabolites and milk composition. The experiment was followed by analyzing the relative transcript abundance of circulating microRNAs (miRNAs) in plasma and targeted miRNA/mRNA expression in peripheral blood mononuclear cells (PBMCs) in both ewes and lambs. FO treatment decreased prepartum feed intake (1812 ± 35 vs 1674 ± 33 g/day, P < 0.01), whereas the influence on plasma metabolites was negligible. Dietary FO supplementation decreased milk fat percentage (8.82 ± 0.49 vs 7.03 ± 0.45, P = 0.02) and reduced milk n-6/n-3 (P < 0.05). Also, it altered the expression of plasma-circulating miRNAs in both ewe and lamb (P < 0.05). Furthermore, maternal nutrition of FO downregulated the relative expression of miR-33a and miR-146b and transcript abundance of genes IL-1ß (0.41-fold) and NF-κB (0.25-fold) in lambs' PBMC. In conclusion, results showed that FO supplementation starting antepartum affects milk composition and circulating miRNA in dams and the inflammatory markers in lambs delivered by the supplemented ewes. These may provide a strategy to maintain immune balance during gestation and develop the immune system in lambs.

Deep transcriptome analysis using RNA-Seq suggests novel insights into molecular aspects of fat-tail metabolism in sheep.

Fat-tail content of sheep breeds is varied and the molecular mechanisms regulating fat-tail development have not been well characterized. Aiming at better identifying the important candidate genes and their functional pathways contributing to fat deposition in the tail, a comparative transcriptome analysis was performed between fat- (Lori-Bakhtiari) and thin-tailed (Zel) Iranian sheep breeds using RNA-seq. The experiment was conducted on six male lambs (three lambs per each breed) at seven months of age. Four different combinations of aligners and statistical methods including Hisat2 + edgeR, Hisat2 + DESeq2, STAR + edgeR and STAR + DESeq2 were used to identify the differentially expressed genes (DEGs). The DEGs were selected for functional enrichment analysis and protein-protein interaction (PPI) network construction. Module analysis was also conducted to mine the functional sub-networks from the PPI network. In total, 264 genes including 80 up- and 184 down-regulated genes were identified as DEGs. The RNA-Seq results were validated by Q-RT-PCR. Functional analysis of DEGs and the module analysis of PPI network demonstrated that in addition to pathways affecting lipid metabolism, a series of enriched functional terms related to "response to interleukin", "MAPK signaling pathways", "Wnt signaling pathway", "ECM-receptor interaction", "regulation of actin cytoskeleton", and "response to cAMP" might contribute to the deposition of fat in tails of sheep. Overall results using RNA-Seq analysis characterized important candidate genes involved in the fatty acid metabolism and regulation of fat deposition, suggesting novel insights into molecular aspects of fat-tail metabolism in sheep. Selected DEGs should be further investigated as potential markers associated with the fat-tail development in sheep breeds.

Encapsulation of soybean meal with fats enriched in palmitic and stearic acids: effects on rumen-undegraded protein and in vitro intestinal digestibility.

Fat coating of soybean meal (SBM) can reduce its protein degradability in the rumen, but the encapsulation of SBM with palmitic (PA) and stearic acids (SA) has not yet been investigated, despite both fatty acids are common energy sources in dairy cow diets. This study aimed to evaluate the effects of applying a novel method, using either 400 or 500 g fat/kg (treatments FL40 and FL50, respectively), which was enriched in PA and SA at different ratios (100:0, 75:25, 50:50, 25:75 and 0:100), on physical and chemical characteristics, ruminal degradability, solubility and in vitro intestinal protein digestibility (IVIPD) of the obtained products. Encapsulation of SBM in fat resulted in greater mean particle size and lower bulk density and protein solubility than unprotected SBM (USBM). Treatment FL50 resulted in increased (p < 0.01) rumen-undegraded protein (RUP) compared to USBM. There were no differences in RUP of SBM when different PA: SA ratios were used. The mean RUP content of treatments FL40 and FL50 (306 and 349 g/kg, respectively) was greater compared to USBM (262 g/kg, p < 0.05), but lower than that for a standard heat-treated SBM (431 g/kg). Values of IVIPD did not differ among SBM, heat-treated SBM and FL40 and FL50 samples, all being greater than 97.8%. In conclusion, encapsulation of SBM with fats enriched in PA and SA proved to be effective in reducing protein solubility and increasing RUP without depressing protein digestibility in the intestine. For validation of the method, in vivo research to investigate the effects of these products on the production of dairy cows is warranted.