Ruminal Drinkers: Endocrine and Metabolic Status and Effects of Suckling from a Nipple Instead of Drinking from a Bucket

Early Feeding Regime of Waste Milk, Milk, and Milk Replacer for Calves Has Different Effects on Rumen Fermentation and the Bacterial Community

Simple Summary

The postnatal period may be the most critical window for rumen manipulation, and the early feeding regime may lead to permanent changes in the rumen microbial composition. The objective of this research was to investigate the effects of the most common liquid feeds (whole milk, waste milk, and milk replacer) on growth performance, rumen development, and the ruminal bacterial community during the weaning period, and to then follow calves to up to six months of age to determine the persistence of any ruminal imprinting effects. The results demonstrate that the early feeding regime impacts rumen development not only by dry matter intake, but also the type of liquid feed. Calves fed waste milk had a distinctly structured bacterial community at two months of age, but this difference diminished at six months of age. Calves fed milk replacer had a different rumen fermentation pattern at two months of age, which may induce a long-lasting effect on the rumen environment.

Abstract

We investigated the effects of different types of early feeding on rumen fermentation parameters and the bacterial community in calves. Fifty-four Holstein calves were assigned to three treatments and fed whole milk (M), pasteurized waste milk (WM), or milk replacer (MR). Male calves were slaughtered at the age of two months to measure the stomach masses. The female calves were followed for six months to determine the body weight, blood indices, rumen fermentation, and ruminal bacterial community. At the age of two months, the average daily gain was lower, but the concentration of total volatile fatty acids was greater in the MR group. Starter intake and stomach mass were lower, but the isovalerate molar proportion was greater in the WM group. The blood indices and ruminal bacterial community of the WM group differed from those of the other groups. At the age of six months, the ruminal propionate molar proportion was lower, but the ruminal pH and acetate/propionate ratio were greater in the MR group. In conclusion, calves fed WM had different rumen fermentation and bacterial community during the weaning period, whereas feeding MR produced a long-lasting effect on the rumen environment.

Digestive processes in ruminal drinkers characterized by means of the acetaminophen absorption test

The aim of the present study was to measure transit patterns of nutrients and the absorptive ability in ruminal drinkers (RDs) compared with healthy unweaned calves. The acetaminophen (paracetamol) absorption test was used to characterize the oroduodenal transit rate. Clinical examination and the analysis of various blood parameters provided supplementary information on digestive processes. Three unweaned bucket-fed calves (one RD and two healthy controls) each from seven Swiss dairy farms were included in the study. Measurements (tests 1 and 2) were performed twice at an interval of 10 days. Between tests, the feeding technique of the RDs and one control calf per farm was changed to feeding with a nipple instead of by bucket (without nipple). Acetaminophen appearance in the blood was delayed and reduced in RDs compared with the controls. Acid-base metabolism and several haematological and metabolic parameters differed markedly between RDs and healthy controls. The characteristics of the oroduodenal transit rate, absorptive abilities and clinical status in RDs were nearly normalised within 10 days of reconditioning.

Separation of protein and lactose intake over meals dissociates postprandial glucose and insulin concentrations and reduces postprandial insulin responses in heavy veal calves

The present study examined, at identical daily nutrient intakes, the impact of separating protein and lactose intakes across two daily meals on the metabolic and endocrine status in heavy veal calves. Calves were assigned to one of six degrees of separating protein and lactose over the two meals (termed nutrient synchrony, SYN 1-6; 6 calves/treatment). They were fed the protein-rich (P-)meal and the lactose-rich (L-)meal at 06:00 and 18:00h, respectively, or vice versa. At SYN 1, calves were fed with 50% of the daily protein and 50% of the daily lactose intake in each meal. Protein and lactose were iso-energetically exchanged between the two daily meals from SYN 1 to 6. At SYN 6, 85% of the daily protein and 20% of the daily lactose was fed in the P-meal and the remainder in the L-meal. Blood samples were collected hourly during 24h. Mean 24h glucose concentrations increased and insulin concentrations decreased from SYN 1 to 6. Postprandial 5h areas under concentration curves (AUC(0-5h)) of glucose increased with increasing meal lactose content. AUC(0-5h) of non-esterified fatty acids increased after P- and L-meals from SYN 1 to 6. Urea concentrations increased after L-meals from SYN 1 to 6, but decreased after P-meals from SYN 1 to 6. Insulin AUC(0-5h) decreased after L-meals and after P-meals from SYN 1 to 6. Nutrient asynchrony did not affect insulin-like growth factor-1, glucagon, growth hormone, leptin, 3,5,3'-triiodothyronine and thyroxine. In conclusion, separation of protein and lactose intake over meals inhibited insulin responses to a lactose-rich meal in heavy veal calves despite high plasma glucose concentrations.

Postprandial blood hormone and metabolite concentrations influenced by feeding frequency and feeding level in veal calves

This study hypothesized that increased feeding frequency (FF) decreases problems with glucose homeostasis seen at high feeding levels (FL) in heavy veal calves. Effects of FF and FL on hormone and metabolite concentrations were studied in 15 heavy veal calves fed once (FF1; at 12:00), twice (FF2; at 12:00 and 24:00) or four times daily (FF4; at 06:00, 12:00, 18:00 and 24:00). In period 1, all calves were fed at a low FL (FL(low); 1.5 x metabolizable energy requirements for maintenance, ME(m)). In period 2, FF2 and FF4 calves were fed at high FL (FL(high); 2.5 x ME(m)), whereas FF1 calves were still fed at FL(low). Blood was sampled every 30 min from 12:00 to 18:00 and postprandial integrated plasma hormone and metabolite concentrations (AUC(12-18 h)) were calculated. Glucose AUC(12-18 h) increased with increasing FL, but decreased with increasing FF, urea AUC(12-18 h) increased with increasing FL, whereas non-esterified fatty acid AUC(12-18 h) were unaffected by FL and FF. Insulin AUC(12-18 h) decreased with increasing FF and decreasing FL. Glucagon AUC(12-18 h) increased with increasing FL and FF. Growth hormone AUC(12-18 h) decreased, whereas insulin-like growth factor-1 and leptin AUC(12-18 h) increased with increasing FL. Mean thyroxine and 3,5,3'-triiodothyronine concentrations were modified by FF and FL. There were no FF x FL interactions, except for plasma glucose. In conclusion, postprandial hormone and metabolite responses were differentially affected by FF and (or) FL. Glucose and insulin concentrations were maximally increased at high FL and low FF. Hyperglycemia, glucosuria and excessive insulinemia were prevented by increasing FF and decreasing FL.

Effect of Roughage Source and Roughage to Concentrate Ratio on Animal Performance and Rumen Development in Veal Calves

Sixty-four male Holstein-Friesian x Dutch Friesian veal calves (46 +/- 3.0 kg) were used to evaluate the effect of the inclusion of different levels and sources of dietary roughage on animal performance and rumen development. Treatments consisted of 1) C100 = concentrate only; 2) C70-S30 = concentrate (70%) with straw (30%), 3) C70-G30 = concentrate (70%) with dried grass (30%), 4) C70-G15-S15 = concentrate (70%) with dried grass (15%) and straw (15%), 5) C70-CS30 = concentrate (70%) with corn silage (30%), 6) C40-CS60 = concentrate (40%) with corn silage (60%), 7) C70-CS30-AL = concentrate (70%) with corn silage (30%) ad libitum, 8) C70-G15-S15-AL = concentrate (70%) with dried grass (15%) and straw (15%) ad libitum. All dietary treatments were provided in addition to a commercial milk replacer. Concentrate was provided as pellets and roughage was chopped. The dietary treatments 1 to 6 were supplied restrictedly to a maximum of 750 g of dry matter (DM) per day, whereas treatments 7 and 8 were offered ad libitum in combination with a reduced amount of milk replacer. Calves were euthanized after 10 wk. Straw supplementation (C70-S30 vs. C70-G30 and C70-CS30) reduced DM intake, and ad libitum supply of concentrate and roughage increased DM intake. Roughage addition did not affect growth performance. Rumen fermentation was characterized by low pH and high total volatile fatty acids and reducing sugar concentrations. Calves fed ad libitum showed lower ruminal lactate concentrations than calves fed restrictedly. Ammonia concentrations were highest in calves fed C-100 and lowest in calves fed ad libitum. The recovery of CoEDTA (added to milk replacer) varied between 20.5 and 34.9%, indicating that significant amounts of milk entered the rumen. Roughage addition decreased the incidence of plaque formation (rumen mucosa containing focal or multifocal patches with coalescing and adhering papillae covered by a sticky mass of feed, hair and cell debris) and the incidence of calves with poorly developed rumen mucosa. However, morphometric parameters of the rumen wall were hardly influenced by the type and level of roughage. Ruminal polysaccharide-degrading enzyme activities reflected the adaptation of the microorganisms to the dietary concentrate and roughage source. Results indicated that in veal calves, the addition of roughage to concentrate diets did not affect growth performance and positively influenced the macroscopic appearance of the rumen wall.