Evaluation of bovine colostrum replacer supplementation to improve weaning transition in Holstein dairy calves.

The objective of this randomized controlled trial was to evaluate the efficacy of supplementing bovine colostrum replacer during weaning to reduce intestinal permeability and improve gain. For this experiment, 65 calves were enrolled and housed individually until 70 d of age. Calves were fed milk replacer (150 g/L) 3 times daily with 9, 10.5, 11.25, and 12 L/d offered from d 1 to 7, 8 to 14, 15 to 21, 22 to 56, respectively. Calves were weaned over 8 d from d 57 to 64, receiving a total of 7.8 L in 2 meals per day from d 57 to 60 and 3.8 L/d in 1 feeding from d 61 to 64. At d 57, calves were blocked by birth weight and randomly assigned to 1 of 2 treatments, equal in ME, which were fed once daily during weaning from d 57 to 64: control (CON; n = 31 calves): 3.8 L of milk replacer (150 g/L) fed by nipple bottle, or colostrum supplementation (COL; n = 34): a mixture of 1 L of bovine colostrum replacer (125 g/L) and 3 L of milk replacer (150 g/L) with 3.8 L of of the mixture fed by nipple bottle. Serum IgG was measured within 48 h of birth and BW was taken at d 0, 57, 60, 64, 70, 77, and 84. Starter intake and bovine respiratory disease (BRD) score were measured daily from d 50 to 70, and fecal consistency was examined daily from d 56 to 70. Serum BHB and lung consolidation were evaluated at d 57, 64, and 70, and intestinal permeability was assessed by recovery of chromium-EDTA, lactulose, and d-mannitol from plasma after oral administration at d 56 and 65. Body weight had no difference between treatment groups at the start of weaning, but COL were 2.79 kg (95% CI: 0.90-4.68) and 2.76 kg (95% CI: 0.86-4.65) heavier than CON at d 77 and 84, respectively. Additionally, COL tended to gain 100.00 g/d more than CON calves (95% CI: -10.41-207.13) from d 57 to 84. No differences were observed in any of the other variables measured. Supplementation of bovine colostrum replacer during weaning may improve weight gain, but the mechanism of action is not clear.

A comparison of post-ruminal provision of Ca-gluconate and Ca-butyrate on growth performance, gastrointestinal barrier function, short-chain fatty acid absorption, intestinal histology, and brush-border enzyme activity in beef heifers.

The objective of this study was to compare the effects of post-ruminal provision of Ca-butyrate (CaB) when delivered via abomasal dosing, and Ca-gluconate (CaG) when provided ruminally using a rumen protected form or using an unprotected form via abomasal dosing on short-chain fatty acid (SCFA) concentration throughout the GIT, nutrient digestibility, GIT barrier function, ruminal SCFA absorption, ruminal morphometrics, intestinal brush border enzyme activity, and blood parameters for beef heifers. Thirty-two beef heifers fitted with ruminal cannulas were used in a randomized complete block design and assigned to one of four treatments: 1) negative control (ruminal infusion of double-distilled water; CON); 2) abomasal infusion of CaB (AB; 0.0029% of BW); 3) abomasal infusion of CaG (AG; 0.0077% of BW); and 4) ruminal infusion of a hydrogenated fat-embedded CaG (RG; 0.0192% of BW) to provide ruminal protection. Excluding CON, treatments were designed to deliver the same amount of butyrate in the small intestine. Heifers were housed in individual pens and DMI was limited to 95% of voluntary intake to minimize a potential confounding effect of DMI on treatment responses. Total GIT barrier function was assessed on day 17 and SCFA disappearance was evaluated on day 21 using the temporarily isolated and washed reticulo-rumen technique. On day 28, heifers were slaughtered, and ruminal and colonic digesta were collected to assess SCFA concentration. Additionally, ruminal, jejunal, and colonic tissues were collected to assess SCFA fluxes and regional barrier function ex vivo using the Ussing chamber technique. For colonic digesta, both AB and CaG treatments reduced the proportion of acetate (P < 0.05) and increased the proportion on propionate (P < 0.05) compared to CON. Relative to CON, AB but not CaG treatments increased in vivo ruminal disappearance of total SCFA (P = 0.01), acetate (P = 0.03), propionate (P = 0.01), and butyrate (P > 0.01). Treatments did not affect (P ≥ 0.10) acetate and butyrate fluxes in the ruminal and colonic tissues when measured ex vivo; however, when compared with CON, AB tended to decrease (P = 0.09) mannitol flux across ruminal tissue. In addition, mannitol flux was affected (P < 0.01) by region, with greater mannitol flux across the jejunum than rumen and colon. We conclude that while both abomasal infusion of CaB and CaG affect the molar proportion of acetate and propionate in the colon, only abomasal CaB stimulated ruminal SCFA absorption for growing beef heifers.

Butyrate, a short-chain fatty acid (SCFA), has received attention due to its ability to promote gastrointestinal (GIT) health and development. However, butyrate in its free form presents a strong odor, limiting its use in diet formulation. Supplementation of butyrate precursors, such as gluconate, have been studied to enhance butyrate production in the GIT. This study evaluated the effects of post-ruminal infusion of Ca-butyrate (AB; 0.0029% of BW) and Ca-gluconate (AG; 0.0077% of BW) and ruminal infusion of a hydrogenated fat-embedded Ca-gluconate (RG; 0.0192% of BW) relative to control (CON; ruminal infusion of double-distilled water). Thirty-two beef heifers fitted with ruminal cannulas were fed for 28 d and GIT barrier function and ruminal SCFA absorption were assessed. At slaughter, the rumen, jejunum, and colon tissues were collected and barrier function and SCFA fluxes were assessed ex vivo. Relative to CON, AB but not AG and RG increased in vivo ruminal SCFA absorption and tended to increase ex vivo barrier function. Thus, the data presented in this study shows that butyrate and gluconate do not function through the same mode of action in the GIT of beef heifers.

Effects of replacing inorganic salts of trace minerals with organic trace minerals in the pre- and postpartum diets on mineral status, antioxidant biomarkers, and health of dairy cows.

Our objectives were to evaluate the effects of complete replacement of supplementary inorganic salts of trace minerals (ITM; cobalt (Co), copper (Cu), manganese (Mn), zinc (Zn) sulfates and sodium (Na) selenite) by organic trace minerals (OTM; Co, Cu, Mn, Zn proteinates, and selenized yeast) in both pre- and postpartum diets on trace minerals (TM) concentrations in body fluids and liver, antioxidant and inflammation biomarkers in blood, and postpartum health of dairy cows. Pregnant cows were blocked by parity and body condition score and randomly assigned to ITM (n = 136) or OTM (n = 137) 45 d before expected calving. Both groups received the same pre- and postpartum diets except for the source of supplementary TM. The day of calving was considered study d 0 and blood was collected on d -45, -21, -14, -10, -7, -3, 0, 3, 7, 10, 14, 23, 65, and 105 for analyses of TM and biomarkers. Concentrations of TM were also investigated in the liver (d 105), milk (d 7, 23, 65, 105), urine (d -21, 21, 65, 105), ruminal fluid and feces (d -21, 21, 65). Incidence of clinical and subclinical health conditions were evaluated. Complete replacement of ITM by OTM resulted in greater concentration of selenium (Se) in serum (0.084 vs. 0.086 µg/mL; P < 0.01), milk (0.24 vs. 0.31 µg/g; P < 0.01), and ruminal fluid (0.54 vs. 0.58 µg/g; P = 0.06), and reduced concentration of Se in urine (1.54 vs. 1.23 µg/g; P<0.01). For concentration of Co in serum, an interaction between treatment and time was detected (P < 0.01). Cows supplemented with OTM had greater concentrations of Co on d -7 and 0 (0.30 vs. 0.33 ng/mL; P < 0.01) but lower concentrations of Co on d 23, 65, and 105 (0.34 vs. 0.31 ng/mL; P < 0.05), in addition to reduced concentration of Co in feces (1.08 vs. 0.99 µg/g; P = 0.04) and, for multiparous only, in urine (0.019 vs. 0.014 µg/g; P < 0.01). Cows supplemented with OTM had lower postpartum concentrations of glutamate dehydrogenase (20.8 vs. 17.8 U/L; P < 0.05) and higher albumin on d -10 (36.0 vs. 36.7 g/L; P = 0.04) and 23 (36.9 vs. 37.6 g/L; P = 0.03) relative to calving. Primiparous cows fed OTM had lower concentration of ceruloplasmin in plasma (55 vs. 51 mg/L; P ≤ 0.05). Cows supplemented with OTM had less incidence of lameness (14% vs. 7%; P = 0.05), elevated nonesterified fatty acids (NEFA) (61% vs. 44%; P < 0.01), and multiple metabolic problems (35% vs. 20%; P < 0.01). Despite the lack of differences in Cu, Mn, and Zn concentrations and antioxidant capacity, complete replacement of ITM by OTM altered concentrations of Se and Co, supported liver and hoof health, and reduced the risk of postpartum elevated NEFA.

Trace minerals (TM) are important for oxidative balance and immunity of cows. Different forms of TM are available for dietary supplementation of dairy cows. We tested whether replacing inorganic salts of TM by organic sources of TM in both pre- and postpartum diets improve TM concentration in body fluids and liver, antioxidant capacity in blood, and postpartum health of dairy cows. Despite the lack of difference in antioxidant capacity and in concentrations of Cu, Mn, and Zn, the complete replacement of inorganic salts by organic sources altered concentrations of Se and Co in circulation, and reduced the concentration of biomarkers associated with inflammation and liver damage, and the risk of lameness and postpartum metabolic problems.

A proof of principle study investigating the effects of supplemental concentrated brewer's yeast on markers of gut permeability, inflammation, and fecal metabolites in healthy non-challenged adult sled dogs.

Yeast-derived ß-glucans impact immunity, though their effects on gut permeability and inflammation are less understood. Most research has investigated other components of the yeast cell wall, such as the prebiotic mannan- and fructo-oligosaccharides. The objective of this study was to assess the effects of feeding a concentrated yeast product on markers of inflammation (serum amyloid A [SAA] and haptoglobin [Hp]) and oxidative status (malondialdehyde [MDA]), fecal products of fermentation, and gut permeability. Nineteen privately owned domestic Siberian huskies, and one Alaskan husky (9 females: 5 intact, 4 spayed; 11 males: 3 intact, 8 neutered), with an average age of 4.8 ± 2.6 yr and body weight (BW) of 25.6 ± 4.1 kg, were used in this study. Dogs were blocked and randomly allocated to one of two diet groups. Ten dogs received a dry extruded diet. The other 10 received the same diet top dressed with yeast for a daily ß-glucan dose of 7 mg/kg BW for 10 wk. Fecal collection, for evaluation of fecal metabolites, and scoring occurred weekly. Gut permeability was assessed using the chromium-labeled ethylenediamine tetra-acetic acid (Cr-EDTA) and iohexol markers prior to the initiation of dietary treatment and after 10 wk of treatment. Blood samples were collected premarker administration and 0.5, 1, 2, 3, 4, 5, and 6 h postadministration. Fasting concentrations of SAA, Hp, and MDA were measured on weeks -1, 2, 4, and 8. Incremental area under the curve (I-AUC) was calculated for serum iohexol and Cr-EDTA concentrations. All data were analyzed using PROC GLIMMIX of SAS with dog as random effect, and week as fixed effect and repeated measure. Dogs receiving treatment tended to have decreased I-AUC of Iohexol (P = 0.10) and Cr-EDTA (P = 0.06) between baseline and cessation of treatment compared to the change over time in I-AUC for control (Ctl) dogs. Treatment dogs had lower Hp concentrations (P ≤ 0.05) than Ctl. There were no differences between treatments for SAA and MDA concentrations (P > 0.05). Fecal arabinose concentrations were greater in treatment (Trt) dogs (P ≤ 0.05) compared to Ctl, though no other fecal metabolites were affected by treatment. There was no difference in the relative frequency of defecations scored at any fecal score between Trt and Ctl dogs, and mean score did not differ between groups (P > 0.10). These data suggest that concentrated brewer's yeast may have the potential to reduce gut permeability without impacting inflammatory status and markers of health in adult dogs.

This study evaluated the effects of concentrated brewer's yeast on gut health in dogs. Nineteen Siberian Huskies and one Alaskan husky were blocked and randomly allocated to one of two groups. Treatment dogs received a yeast supplement for 10 wk, while control dogs received no supplement. Dogs were administered two markers to assess intestinal permeability prior to start of treatment and following 10 wk of treatment. Blood samples were collected and analyzed for markers of inflammatory status (serum amyloid A [SAA] and Haptoglobin [Hp]) and oxidative status (serum malondialdehyde [MDA]). Fecal samples were collected weekly to assess fecal score as well as fecal metabolite concentrations. Intestinal permeability was reduced in treatment dogs following treatment, and no change was observed in the control group. Treatment dogs had lower Hp concentrations than control (Ctl), but there were no differences between treatments for SAA and MDA. Fecal arabinose concentrations were significantly greater in the treatment group when compared to control. There were no differences in the relative frequency of defecations scored at any fecal score between treatment and Ctl dogs, nor did mean score differ between the groups. This study suggests that concentrated brewer's yeast may reduce gut permeability and inflammation without detrimentally impacting markers of health in adult dogs.

Effect of feeding calcium gluconate embedded in a hydrogenated fat matrix on feed intake, gastrointestinal fermentation and morphology, intestinal brush border enzyme activity and blood metabolites in growing lambs.

Gluconate salts have been identified as a butyrate precursor when fed to non-ruminant species and may increase the butyrate concentration in the large intestine supporting gastrointestinal health and development. The objective of this study was to evaluate the dose response of hydrogenated fat-embedded calcium gluconate (HFCG) on performance and gastrointestinal tract (GIT) development in growing lambs. Thirty-two wether lambs were used in a randomized complete block design and assigned to 1 of 4 treatments differing in the inclusion of HFCG: 0.0% (CON), 0.075% (LOW), 0.30% (MED), and 0.60% of the diet (HIGH). Lambs were allocated into individual pens and fed ad libitum with feed delivered twice daily. Feed intake was recorded daily, and body weight (BW) was assessed at the beginning and the end of the 29-d period. Blood was sampled on day 21, prior to feeding and 6 h post-feeding to evaluate changes in ß-hydroxybutyrate, glucose, and insulin concentrations. Total fecal collection was conducted during days 25 to 28 to assess apparent total tract digestibility. On day 29, lambs were slaughtered, and the entire GIT was separated by region to enable sampling of tissue and digesta. Data were analyzed to assess linear, quadratic, and cubic effects of HFCG dose. Final BW, average daily gain, and dry matter intake decreased linearly (P ≤ 0.02) with increasing HFCG. Increasing inclusion of HFCG linearly decreased (P = 0.01) the thickness of the stratum corneum in ruminal papillae but did not affect other strata (P ≥ 0.34). Omasal digesta weight linearly decreased (P = 0.01) as the concentration of HFCG increased and abomasal digesta weight was cubically affected (P = 0.03) the increasing dose of HFCG. Short-chain fatty acid concentration in the cecum was cubically affected (P < 0.01) with increasing dose of HFCG where low dose had the greatest concentration. Moreover, increasing the dietary supply of HFCG linearly increased the proportion of acetate (P = 0.04) in the cecum and linearly decreased the proportion of propionate in the digesta of both the cecum (P < 0.01) and colon (P = 0.01). Colon crypt depth was quadratically (P = 0.03) affected with the increasing dose of HFCG, where lambs fed MED had greatest crypt depth. We conclude that feeding HFCG to growing lambs did not increase butyrate concentration in the large intestine and consequently does not increase the absorptive surface area of the whole tract, the size of the GIT, or the functionality of the intestine.

Gluconate salts have been reported to be metabolized by microbes in the gastrointestinal tract to yield butyrate. Butyrate has shown potential to enhance functionality of the gastrointestinal tract by increasing the absorptive surface area, enzyme activity, and the barrier function. This study evaluated the inclusion of four levels of hydrogenated fat-embedded Ca-gluconate (HFCG; 0.0%, 0.075%, 0.30%, and 0.60% of the diet) designed to increase the production of butyrate in the large intestine. Thirty-two wether lambs were fed for 28 d, slaughtered, and eviscerated to allow complete evaluation of the gastrointestinal tract and its contents. Growth and dry matter intake decreased linearly with increasing dose of HFCG. Dose of HFCG cubically affected short-chain fatty acid concentration in the cecum with increased concentrations at the 0.075% dose. Moreover, increasing dose of HFCG linearly increased the proportion of acetate and linearly decreased the proportion of propionate in the cecum without altering the proportion of butyrate. Thus, the supplementation of HFCG did not increase butyrate concentration in the large intestine and did not enhance gastrointestinal tract function.

Oversupplying metabolizable protein during late gestation to beef cattle does not influence ante- or postpartum glucose-insulin kinetics but does affect prepartum insulin resistance indices and colostrum insulin content.

The objective of this study was to evaluate whether oversupplying metabolizable protein (MP) during late gestation influences glucose and insulin concentrations, and insulin resistance (IR) in late gestation and early lactation. Crossbred Hereford, first-lactation heifers were individually fed diets to supply 133% (HMP, n = 11) or 100% (CON, n = 10) of their predicted MP requirements for 55 ± 4 d (mean ± SD) prior to calving. All heifers received a common lactation ration formulated to meet postpartum requirements (103% MP and 126% ME). After feed was withheld for 12 h, cattle underwent an intravenous glucose tolerance test (IVGTT) on days -6.7 ± 0.9 and 14.3 ± 0.4 by infusing a 50% dextrose solution (1.36 g glucose/kg BW0.75) through a jugular catheter with plasma collected at -10, 0 (immediately after infusion), 5, 10, 15, 20, 25, 30, 45, 60, 75, 90, and 120 min, respective to the infusion. Glucose and insulin concentrations were assessed. Insulin resistance indices (homeostasis model of insulin resistance [HOMA-IR], quantitative insulin sensitivity check index [QUICKI], revised quantitative insulin sensitivity check index [RQUICK], and RQUICKI incorporating serum beta-hydroxybutyrate concentrations [RQUICKIBHB]) were calculated from measurements of serum non-esterified fatty acids and beta-hydroxybutyrate and plasma glucose and insulin concentrations on days -34 ± 4, -15 ± 4, 7 ± 1, 28 ± 3, 70 ± 3, and 112 ± 3. Colostrum samples were collected within an hour of calving (prior to suckling) and analyzed for insulin concentration. Data were analyzed as a randomized block design using the PROC GLIMMIX of SAS, accounting for repeated measurements when necessary. Baseline (-10 min) plasma glucose and insulin concentrations were elevated (P ≤ 0.038) for HMP heifers during the antepartum IVGTT, but not (P ≥ 0.25) during the postpartum IVGTT. Plasma glucose and insulin concentrations throughout the antepartum or postpartum IVGTT did not differ (P ≥ 0.18) by prepartum treatment, nor did other glucose and insulin IVGTT parameters (i.e., max concentration and time to reach max concentration, nadir values, clearance rates and half-lives, area-under-the-curve, and insulin sensitivity index; P ≥ 0.20). Antepartum IVGTT IR indices indicated that HMP heifers were more (P ≤ 0.011) IR than their counterparts. Similarly, the prepartum HOMA-IR was greater (P = 0.033) for HMP heifers, suggesting increased IR. Postpartum IR indices did not (P ≥ 0.25) indicate that prepartum MP consumption impacted postpartum IR. Colostrum insulin concentration was increased (P = 0.004) by nearly 2-fold for HMP relative to CON heifers. These data demonstrate that prepartum MP overfeeding alters baseline glucose-insulin concentrations in late-pregnant beef heifers and increases colostrum insulin content without having carry-over effects on postpartum glucose-insulin concentrations and IR.

A live yeast supplementation to gestating ewes improves bioactive molecule composition in colostrum with no impact on its bacterial composition and beneficially affects immune status of the offspring.

Colostrum quality is of paramount importance in the management of optimal ruminant growth and infectious disease prevention in early life. Live yeast supplementation effect during the last month of gestation was evaluated on ewes' colostrum composition. Two groups of ewes (n = 14) carrying twin lambs were constituted and twins were separated into groups (mothered or artificially fed) 12 h after birth. Nutrient, oligosaccharides (OS), IgG and lactoferrin concentrations were measured over 72 h after lambing, and bacterial community was described in colostrum collected at parturition (T0). Immune passive transfer was evaluated through IgG measurement in lamb serum. In both groups, colostral nutrient, OS concentrations and IgG concentrations in colostrum and lamb serum decreased over time (P < 0⋅01), except for lactose, which slightly increased (P < 0⋅001), and lactoferrin, which remained stable. Bacterial population was stable over time with high relative abundances of Aerococcaceae, Corynebacteriaceae, Moraxellaceae and Staphylococcaceae in T0 colostrum. No effect of supplementation was observed in nutrient and lactoferrin concentrations. In supplemented ewes, the level of colostral IgG was higher at T0 and a higher level of serum IgG was observed in lambs born from supplemented mothers and artificially fed, while no effect of supplementation was observed in the mothered lamb groups. Using a metabolomic approach, we showed that supplementation affected OS composition with significantly higher levels of colostral Neu-5Gc compounds up to 5 h after birth. No effect of supplementation was observed on bacterial composition. Our data suggest that live yeast supplementation offsets the negative impact of early separation and incomplete colostrum feeding in neonate lambs.

Short communication: Odd-chain and branched-chain fatty acid concentrations in bovine colostrum and transition milk and their stability under heating and freezing treatments.

Although odd-chain fatty acids (OCFA) and branched-chain fatty acids (BCFA) are found in bovine milk and have some positive influences on human and animal health, their concentrations in bovine colostrum and transition milk have not been reported. In this study, we reported the OCFA and BCFA concentrations in colostrum and transition milk and their stability after heating or freezing treatments (or both), which are processes commonly applied in dairy calf management. Milk samples were collected from 12 Holstein dairy cows (6 primiparous and 6 multiparous) at the first milking (colostrum), fifth milking (transition milk), and ninth milking (mature milk) after calving, respectively, and were used for fatty acid analysis using gas chromatography. The sum concentration of OCFA and BCFA (termed OBCFA) was 134 mg/100 g of milk in the colostrum, which was 24% and 35% lower than that in the transition milk and mature milk, respectively. Among these fatty acids detected, C15:0 and C17:0 were the top 2 abundant fatty acids in all milk types, accounting for 20 to 25% and 21 to 24% of the total concentration of OBCFA, respectively. Additionally, anteiso-C17:0 was the most abundant BCFA, followed by iso-C17:0, anteiso-C15:0, iso-C16:0, iso-C15:0, iso-C18:0, and iso-C14:0 in 3 types of milk. Significant interactions between milk type and cow parity were observed for all OCFA and BCFA concentrations. The milk samples were also treated with heating (at 65°C for 60 min), freezing (at -20°C for 30 d), and heating and freezing (at 65°C for 60 min and then at -20°C for 30 d), and milk OCFA and BCFA concentrations were similar between these treatments. In conclusion, the OBCFA concentration was lower in colostrum, compared with transition and mature milks, and it remained stable after heating and freezing treatments.

Effect of colostrum feeding strategies on the expression of neuroendocrine genes and active gut mucosa-attached bacterial populations in neonatal calves.

Colostrum feeding is vital for the development of the immune system and gastrointestinal tract in neonatal calves; however, it is currently unknown whether different colostrum feeding strategies affect their neuroendocrine system and potentially the gut-brain axis. The present study investigated the effect of 3 different colostrum feeding regimens on the expression of neuroendocrine genes in adrenal glands and gastrointestinal tissues and on the abundance of intestinal commensal bacteria. Holstein bull calves were fed colostrum immediately after birth and randomly assigned to 3 groups: whole milk (n = 8), mixture of 50% colostrum and 50% whole milk (n = 8), and colostrum (CF; n = 8) for 72 h with 12-h intervals. Adrenal glands, ileum, and colon tissues were collected at 75 h and were subjected to the expression of 11 targeted neuroendocrine genes and the abundance of tissue mucosa-associated bacteria measurement using quantitative real-time PCR and quantitative PCR, respectively. The expressions of all targeted genes were detected, and the expression of α-adrenergic receptor (ADRA1A) gene was affected by CF in adrenal glands and gut tissues. In addition, CF upregulated the expression of HTR4 (serotonin receptor) and SLC4A4 (serotonin transporter) genes in the ileum and increased the abundance of active Lactobacillus spp. and Escherichia coli (as detected at RNA level) associated with ileum and colon tissue. Furthermore, there were positive correlations between the abundance of active Lactobacillus spp. and E. coli with expression of HTR2B and HTR4 genes in the colon, suggesting that extended colostrum feeding strategies may affect the interaction between gut microbiota and host endocrine functions in neonatal calves.

Correlated seed failure as an environmental veto to synchronize reproduction of masting plants.

Variable, synchronized seed production, called masting, is a widespread reproductive strategy in plants. Resource dynamics, pollination success, and, as described here, environmental veto are possible proximate mechanisms driving masting. We explored the environmental veto hypothesis, which assumes that reproductive synchrony is driven by external factors preventing reproduction in some years, by extending the resource budget model of masting with correlated reproductive failure. We ran this model across its parameter space to explore how key parameters interact to drive seeding dynamics. Next, we parameterized the model based on 16 yr of seed production data for populations of red (Quercus rubra) and white (Quercus alba) oaks. We used these empirical models to simulate seeding dynamics, and compared simulated time series with patterns observed in the field. Simulations showed that resource dynamics and reproduction failure can produce masting even in the absence of pollen coupling. In concordance with this, in both oaks, among-year variation in resource gain and correlated reproductive failure were necessary and sufficient to reproduce masting, whereas pollen coupling, although present, was not necessary. Reproductive failure caused by environmental veto may drive large-scale synchronization without density-dependent pollen limitation. Reproduction-inhibiting weather events are prevalent in ecosystems, making described mechanisms likely to operate in many systems.

Short communication: The effect of heat treatment of bovine colostrum on the concentration of oligosaccharides in colostrum and in the intestine of neonatal male Holstein calves.

The objective of this study was to determine the effect of the heat treatment (HT, 60°C for 60 min) on the concentration of bovine colostrum oligosaccharides (bCO) in pooled bovine colostrum and the intestine of neonatal male Holstein calves after feeding. First-milking colostrum was pooled from both primiparous and multiparous cows, and half of the pooled colostrum was heat-treated at 60°C for 60 min (HC), whereas the other half was not heat-treated and remained fresh (FC). At birth, 32 male Holstein calves were randomly assigned to 1 of 3 treatment groups: (1) control calves that did not receive colostrum for the duration of the experiment and were euthanized at 6 h (NC, n = 4) or 12 h (NC, n = 4), (2) calves fed fresh colostrum (FC) and were euthanized at 6 h (FC, n = 6) or 12 h (FC, n = 6), or (3) calves fed heat-treated colostrum (HC) and euthanized at 6 h (HC, n = 6) or 12 h (HC, n = 6). All calves were fed 2 L of colostrum within 1 h after birth. At dissection, digesta of the distal jejunum, ileum, and colon was collected and analyzed by liquid chromatography-mass spectrometry to determine the concentration of bCO within each intestinal region. The heat-treated colostrum displayed numerically higher concentrations of total bCO (3,511.6 µg/g) when compared with fresh colostrum (1,329.9 µg/g), with 3'-sialyllactose being the most abundant bCO in both fresh and HT colostrum. In contrast, calves fed HT colostrum displayed a lower amount of total bCO in the distal jejunum (221.91 ± 105.3 vs. 611.26 ± 265.1 µg/g), ileum (64.97 ± 48.39 vs. 344.04 ± 216.87 µg/g), and colon (25.60 ± 13.1 vs. 267.04 ± 125.81 µg/g) at 6 h of life when compared with calves fed fresh colostrum. No differences were observed in regard to the concentrations of total bCO in the intestine of FC and HC calves at 12 h of life. It is speculated that lower concentrations of bCO in the gastrointestinal tract of HC calves at 6 h of life could be due to the early establishment of beneficial bacteria, such as Bifidobacterium, in HC calves and their subsequent metabolism of bCO as a carbon source. These findings suggest that the heat treatment of colostrum increases the amount of free bCO, which may serve as prebiotics available to microbiota within the intestine of the neonatal calf.