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Introduction
Research in my laboratory is focused on the integration of digestion and metabolism in ruminants, emphasizing the effects of metabolic fuels on energy intake and partitioning. We evaluate effects of diet on type, temporal absorption, and physiological effects of fuels using lactating cows as our primary animal model.
Additional affiliations
September 1987 - January 2021
September 1986 - September 1987
Education
May 1982 - May 1986
September 1978 - May 1982
September 1975 - May 1977
Publications
Publications (238)
The control of energy intake is complex, including mechanisms that act independently (e.g. distention, osmotic effects, fuel-sensing) as well as interacting factors that are likely to affect feeding via their effects on hepatic oxidation. Effects of ruminant diets on feed intake vary greatly because of variation in their filling effects, as well as...
Feed and energy intake of ruminant animals can change dramatically in response to changes in diet composition or metabolic state, and such changes are poorly predicted by traditional models of feed intake regulation. Recent work suggests that temporal patterns of fuel absorption, mobilization, and metabolism affect feed intake in ruminants by alter...
Physical and chemical characteristics of dietary ingredients and their interactions can have a large effect on dry matter intake (DMI) of lactating cows. Physical limitations caused by distension of the reticulo-rumen or other compartments of the gastrointestinal tract often limit DMI of high producing cows or cows fed high forage diets. Fermentati...
Voluntary dry matter intake (VDMI) of forages by ruminants may be limited by distention resulting from restricted flow of digesta through the gastrointestinal tract. An animal's capacity for fill depends on the weight and volume of digesta that causes distention and the flow rate of digesta from the organ in which distention occurs. The reticulorum...
Even under the intensive concentrate feeding systems of ruminant animal production in the United States, forages continue to represent the single most important feed resource. Cell-wall concentration and digestibility limit the intake potential and energy availability of forage crops in beef and dairy production. Identification of cell-wall charact...
Energy intake and partitioning are determined by many interacting factors and their prediction is the Achilles' heel of ration formulation. Inadequate energy intake can limit milk yield and reproductive performance, whereas excessive energy intake will increase body condition, increasing the risk of health and reproductive issues in the subsequent...
Our objective was to evaluate the relative effects of endosperm type and conservation method of corn grain on ruminal kinetics, site of nutrient digestion, and flow of nitrogen fractions to the duodenum in lactating dairy cows. Seven ruminally and duodenally cannulated Holstein cows (73 ± 39 d in milk; mean ± SD) were used in a duplicated 4 × 4 Lat...
Our objective was to evaluate effects of corn grain endosperm type and fineness of grind on feed intake, feeding behavior, ruminal fermentation, and productive performance of lactating cows. Eight ruminally and duodenally cannulated Holstein cows in mid lactation (130 ± 42 d in milk; mean ± standard deviation) were used in a duplicated 4 × 4 Latin...
Our objective was to evaluate effects of corn grain endosperm type and fineness of grind on feed intake, feeding behavior, and productive performance of lactating cows. Eight ruminally and duodenally cannulated Holstein cows in mid lactation (130 ± 42 d in milk; mean ± standard deviation) were used in a duplicated 4 × 4 Latin square design with 21-...
Our objective was to evaluate the effects of corn grain varying in endosperm type and conserved as high-moisture or dry ground corn on dry matter intake (DMI), feeding behavior, ruminal fermentation, and yields of milk and milk components of cows in early to mid-lactation. Seven ruminally and duodenally cannulated Holstein cows (73 ± 39 d in milk;...
Our objective was to determine the effects of uncouplers of oxidative phosphorylation on the metabolism of propionate in liver tissue of dairy cows in the postpartum period. A total of 8 primiparous dairy cows were biopsied for liver tissue explants in 2 block-design experiments. Cows were 5.9 ± 2.8 (mean ± SD) days in milk, and the 2 experiments w...
Our objective was to determine the temporal effects of increasing supply of propionate on propionate metabolism in liver tissue of dairy cows in the postpartum (PP) period. A total of 6 dairy cows [primiparous: n = 3, 9.00 ± 1.00 d PP (mean ± SD) and multiparous: n = 3; 4.67 ± 1.15 d PP] were biopsied for liver explants in a block-design experiment...
Feed intake is controlled through a combination of long-and short-term mechanisms. Homeorhetic mechanisms allow adaptation to changes in physiological states in the long term, whereas homeostatic mechanisms are important to maintain physiological equilibrium in the short term. Feed intake is a function of meal size and meal frequency that are contr...
Optimal forage allocation and supplementation strategies for dairy cattle must consider
variation in forage quality characteristics as well as cow’s responses to their diet throughout
lactation. Forage quality characteristics can affect diet cost, energy intake and partitioning,
feed conversion efficiency (FCE), and animal health. These characteris...
Our objective was to evaluate the effects of diet starch concentration and starch fermentability on inflammatory response markers and oxidant status during the early postpartum (PP) period and its carryover effects. Fifty-two multiparous Holstein cows were used in a completely randomized block design experiment with a 2 × 2 factorial arrangement of...
The control of feed intake is complex with mechanisms to ensure an adequate supply of nutrients to meet requirements as well as to prevent their overconsumption. These include short-term controls to maintain physiological equilibrium (homeostasis) as well as coordinated changes necessary to support alterations in physiological state (homeorhesis)....
Our objective was to determine the effects of uncouplers of oxidative phosphorylation on feeding behavior of lactating dairy cows. We hypothesized that uncouplers of oxidative phosphorylation would increase meal size and meal length and performed 2 experiments to test our hypothesis. In experiment 1, 4 late-lactation cows (345 ± 48.4 d in milk; mea...
The objective of this study was to determine the effects of 2 amounts of propionic acid (PA) infused intraruminally at 2 rates of infusion at the initiation of meals on the feeding behavior of Holstein cows in the postpartum period. We hypothesized that the amount and length of time of infusions would interact to affect feeding behavior: rapid infu...
A faster rate of infusion of propionic acid into the rumen of cows in the postpartum period increased meal size compared with a slower rate of infusion in a previous experiment. Because propionate is anaplerotic and stimulates oxidation of acetyl coenzyme A (CoA) in the liver, and hepatic oxidation has been linked to satiety, this result was opposi...
Effects of culture pH and corn oil (CO) concentration on biohydrogenation (BH) of unsaturated fatty acids and disappearance of neutral detergent fiber (NDF) in batch culture were evaluated in a 2 × 3 factorial design experiment. Culture vessels (100 mL; 4 replicates/treatment per time point) included ground alfalfa hay plus CO at 0, 1, or 2% dry ma...
Our objective was to evaluate the effects of starch concentration and starch fermentability of diets fed during the early postpartum (PP) period on DM and energy intake and production. Fifty-two multiparous Holstein cows were used in a completely randomized block design with a 2 X 2 factorial arrangement of treatments. Treatment diets were formulat...
The objective of this research was to identify potential
short-term metabolic bottlenecks of propionate
metabolism in the liver of dairy cows in the postpartum
(PP) period and how such bottlenecks are affected by
feeding status. Propionate, produced primarily from
the fermentation of starch, decreases dry matter intake
for cows in the postpartum pe...
Our objective was to predict the dry matter intake
(DMI) response during ration formulation to factors
related to the filling effect of rations and their interaction
with milk yield (MY) by lactating cows past
peak lactation. A data set was developed consisting of
134 treatment means from 34 experiments reported in
32 peer-reviewed articles publish...
Our objective was to model dry matter intake (DMI)
by Holstein dairy cows based on milk energy (MilkE),
body weight (BW), change in BW (ΔBW), body condition
score (BCS), height, days in milk (DIM), and
parity (primiparous and multiparous). Our database
included 31,631 weekly observations on 2,791 cows enrolled
in 52 studies from 8 states of the Uni...
The objective of this study was to determine the
effects of 2 amounts of propionic acid (PA) infused
intraruminally at 2 rates of infusion at the initiation of
meals on the feeding behavior of Holstein cows in the
postpartum period. We hypothesized that the amount
and length of time of infusions would interact to affect
feeding behavior: rapid infu...
Our objective was to evaluate the effects of diet starch concentration and fermentability on energy intake and energy balance during the early postpartum (PP) period. Fifty-two multiparous Holstein cows were used in a randomized block design experiment with a 2 × 2 factorial arrangement of treatments. Treatment rations were formulated to 22% or 28%...
OBJECTIVE To determine whether Mycobacterium bovis remains viable in ensiled forages.
SAMPLE Alfalfa, mixed mostly grass, and corn silages.
PROCEDURES For each of 10 sampling days, six 250-g replicate samples of each feedstuff were created and placed in a film pouch that could be vacuum sealed to simulate the ensiling process. Within each set of re...
Ruminal microbes partially degrade dietary protein and synthesise microbial protein, which, along with undegraded true protein, contributes to metabolisable protein for the animal. Rumen models have been developed over the past several decades in an effort to better predict metabolisable protein supply for ration formulation for ruminants. These mo...
The daily patterns of feed intake and rumination influence rumen fermentation, rumen pH, and timing of absorbed nutrients in the dairy cow, but the effects of diet composition on these patterns are not well characterized. Data from 3 previously published experiments were examined to determine the influence of dietary starch, fiber, and fatty acids...
Optimal forage allocation and supplementation strategies for dairy cattle must
consider variation in forage quality characteristics as well as cow’s responses to
their diet throughout lactation. Forage quality characteristics can affect diet cost,
energy intake and partitioning, feed conversion efficiency (FCE), and animal
health. These characteris...
The objective of the experiment was to determine if factors such as endosperm type (floury vs. vitreous) and particle size (fine vs. medium) of dry corn grain, known to affect starch digestibility in the rumen, modify apparent ruminal synthesis and duodenal flow of B vitamins in lactating dairy cows. Eight lactating multiparous Holstein cows equipp...
The objective of this study was to evaluate the effects of diet starch concentration and fermentability (SF) fed during the early postpartum (PP) period on dry matter intake (DMI), yields of milk and milk components, body reserves, and metabolism. Fifty-two multiparous Holstein cows were used in a randomized block design with a 2 × 2 factorial arra...
Absorbed fuels from the digestion of starch include propionic acid (PA) produced by ruminal fermentation and glucose (GLU) from intestinal digestion, which may be partially metabolized to lactic acid (LA) by intestinal tissues. Our objective was to evaluate the effects of these fuels on dry matter intake (DMI) and feeding behavior of cows in the po...
Forages are the primary source of physically effective fiber, which is important for normal rumen function. • Physically effective fiber is more filling than other diet components and can limit feed intake. • Feed intake is most limited by rumen fill for high-producing cows and cows fed high forage diets. • The filling effect of a diet is determine...
Effects of continuous isomolar infusions of acetic acid (AcA) or sodium acetate (NAc) infused into the rumen (RU) or into the abomasum (AB) on feeding behavior, dry matter intake (DMI), and metabolic response of cows in the early postpartum period were evaluated. Six rumen-cannulated multiparous Holstein cows (11.8 ± 3.9 d in milk; mean ± SD) were...
The objective of this study was to determine the temporal effects of intraruminal infusion of propionic acid at the initiation of meals on feeding behavior of cows in the postpartum period. Propionic acid derived from ruminal fermentation can reduce energy intake of dairy cows. The suppression of appetite by propionic acid is likely caused by a sig...
Our objective was to determine the effects of dry matter intake (DMI), body weight (BW), and diet characteristics on total tract digestibilities of dry matter, neutral detergent fiber, and starch (DMD, NDFD, and StarchD, respectively) in high-producing dairy cows. Our database was composed of 1,942 observations from 662 cows in 54 studies from Mich...
We hypothesized that the addition of limiting AA increases dry matter intake (DMI) by reducing anaplerosis and hepatic oxidation. Accordingly, the objective of this work was to examine the effects of short-term intravenous infusions of Met, Lys, and His (which are considered the most limiting AA) on DMI as a method to detect whether specific AA are...
The effect of fat supplements (FS) providing different proportions of saturated (SFA) and unsaturated (UFA) fatty acids on supply, apparent ruminal synthesis (ARS), and duodenal flow (DF) of some B vitamins (thiamine, riboflavin, niacin, vitamin B6, folates, and vitamin B12) were evaluated in an experiment using 8 ruminally and duodenally cannulate...
Apparent ruminal synthesis and duodenal flow of thiamin, riboflavin, niacin, vitamin B6, folates, and vitamin B12 were evaluated in an experiment using 15 ruminally and duodenally cannulated lactating Holstein cows fed a basal diet, according to a crossover design, supplemented or not with 56 g/d of Saccharomyces cerevisiae fermentation product. Du...
Appetite suppression during the postpartum (PP) period is likely caused by a signal related to hepatic oxidation of fuels. Faster absorption and hepatic uptake of propionate is expected to accelerate hepatic oxidation, stimulating satiety sooner, reducing meal size. However, if excessive propionate absorption from the rumen results in less efficien...
Development of equations to predict dry matter intake of lactating cows using factors affecting the filling effect of rations. Our objective was to predict dry matter intake (DMI) by lactating cows using factors related to the filling effect of rations. A database of 156 treatment means from 44 experiments reported in the literature was developed....
The objective of this study was to determine the effects of anaplerosis of the tricarboxylic acid cycle on feeding behavior and energy intake of cows in the postpartum period. We infused propionic acid (PA) and glycerol (GL) continuously into the abomasum and hypothesized that PA will decrease meal size and energy intake compared with GL because PA...
Feed intake is affected by the interaction of diet characteristics, physiological state of animals, and environmental stressors. The dominant signals controlling feed intake likely change throughout lactation. Control of feed intake is likely dominated by hepatic oxidation of non-esterified fatty acids during transition and propionate in late lacta...
In this paper, we used erroneous values for the molecular weight of thiamin and vitamers of vitamin B6. This error had limited effects on the overall results or statistical significance; however, several values reported in the text and tables are incorrect. The error affected three statements in the abstract (page 1884), in the Vitamin Intake subse...
In this paper, we used erroneous values for the molecular weight of thiamin and vitamers of vitamin B6. This error had limited effects on the overall results or statistical significance; however, several values reported in the text and tables are incorrect. The error affected statements in the Daily Intake, Apparent Ruminal Synthesis, and Duodenal...
The objective of this study was to examine the effects of fructose and phosphate (Pi) infusions on dry matter intake by dairy cows to further understand the mechanisms controlling feed intake related to hepatic energy status. We performed 3 experiments in which we infused fructose and Pi intravenously or abomasally to Holstein cows. The first exper...
Effects of the forage-to-concentrate ratio on apparent ruminal synthesis of thiamine, riboflavin, niacin, vitamin B6, folates, and vitamin B12 were evaluated in an experiment using 14 ruminally and duodenally cannulated Holstein cows. The experiment was a crossover design with two 15-d treatment periods and a 14-d preliminary period in which cows w...
Our study evaluated the dose-dependent effects of a palmitic acid-enriched supplement in basal diets with or without the inclusion of whole cottonseed on nutrient digestibility and production responses of dairy cows. Sixteen Holstein cows (149 ± 56 days in milk) were used in a split plot Latin square design experiment. Cows were blocked by 3.5% fat...
We determined if differences in digestibility among cows explained variation in residual feed intake (RFI) in 4 crossover design experiments. Lactating Holstein cows (n = 109; 120 ± 30 d in milk; mean ± SD) were fed diets high (HS) or low (LS) in starch. The HS diets were 30% (±1.8%) starch and 27% (±1.2%) neutral detergent fiber (NDF); LS diets we...
Our study evaluated the dose-dependent effects of a palmitic acid-enriched supplement in basal diets with or without the inclusion of whole cottonseed on nutrient digestibility and production responses of dairy cows. Sixteen Holstein cows (149 ± 56 DIM) were used in a split plot Latin square design experiment. Cows were blocked by 3.5% FCM and allo...
We determined if differences in digestibility among cows explained variation in residual feed intake (RFI) in 4 crossover design experiments. Lactating Holstein cows (n = 109; 120 ± 30 DIM; mean ± SD) were fed diets high (HS) or low (LS) in starch. The HS diets were 30% (±1.8%) starch and 27% (±1.2%) neutral detergent fiber (NDF); LS diets were 14%...
Effects of plant maturity on apparent ruminal synthesis and post-ruminal supply of B vitamins were evaluated in two feeding trials. Diets containing alfalfa (Trial 1) or orchardgrass (Trial 2) silages harvested either (1) early cut, less mature (EC) or (2) late cut, more mature (LC) as the sole forage were offered to ruminally and duodenally cannul...
Effects of particle length of silages on apparent ruminal synthesis (ARS) and postruminal supply of B vitamins were evaluated in 2 feeding trials. Diets containing alfalfa (trial 1) or orchardgrass (trial 2) silages, chopped to either 19 mm (long cut, LC) or 10 mm (short cut, SC) theoretical particle length, as the sole forage were offered to rumin...
Forty-eight multiparous cows were used in a randomized complete block design experiment with a 2 × 2 factorial arrangement of treatments to determine the interaction between chromium propionate (CrPr) supplementation and sources of corn varying in ruminal starch fermentability on production responses during the postpartum (PP) and carryover periods...
Effective diet formulation requires processing of information and relationships to achieve a goal. The information is often incomplete or inaccurate. Some relationships are quantitative and can be represented in mathematical models, but others are qualitative and difficult to describe with numbers. The goal may be to increase production, maintain a...
Effects of forage family (legume vs. grass) on apparent ruminal synthesis (ARS) and postruminal supply of B vitamins were evaluated in 2 experiments. Diets containing either alfalfa (AL) or orchardgrass (OG) silages as the sole forage were offered to ruminally and duodenally cannulated lactating Holstein cows in crossover design experiments. Experi...
Suppression of appetite during the postpartum (PP) period is likely caused by a signal related to hepatic energy status from oxidation of fuels. Propionic acid (PA) is likely the most important fuel stimulating hepatic oxidation within meals in ruminants. However, PA production rate in the rumen varies greatly among starch sources and the temporal...
The relationship between hepatic acetyl CoA (AcCoA) content and dry matter intake (DMI) was evaluated using 28 multiparous Holstein cows; 14 were early postpartum (PP; 12.6 ± 3.8 d in milk) and 14 were late-lactation cows (LL; 269 ± 30 d in milk). Cows were fed once daily, and DMI was determined for the first 4 h after feeding. Liver and blood samp...
The effects of dietary starch concentration on yield of milk and milk components were evaluated in a crossover design experiment. Holstein cows (n = 32; 115 ± 22 d in milk) with a wide range in milk yield (28 to 62 kg/d) were assigned randomly within level of milk yield to a treatment sequence. Treatments were diets containing 30% dry ground corn (...
To evaluate propylene glycol (PG) and glycerol (G) as potential treatments for ketosis, we conducted 2 experiments lasting 4 d each in which cows received one bolus infusion per day. Blood was collected before infusion, over 240 min postinfusion, as well as 24 h postinfusion. Experiment 1 used 6 ruminally cannulated cows (26 ± 7 d in milk) randomly...
The effects of dietary starch concentration on yield of milk and milk components were evaluated in a crossover design experiment. Holstein cows (n = 32; 115 ± 22 d in milk) with a wide range in milk yield (28 to 62 kg/d) were assigned randomly within level of milk yield to a treatment sequence. Treatments were diets containing 30% dry ground corn (...
Residual feed intake (RFI) is a tool to quantify feed efficiency in livestock and is commonly used to assess feed efficiency independent of production level, body weight (BW), or BW change. Lactating Holstein cows (n = 109; 44 primiparous and 65 multiparous), averaging (mean ± standard deviation, SD) 665 ± 77 kg of BW, 42 ± 9 kg of milk/d, and 120...
Forty-eight multiparous cows were used in a randomized complete block design experiment with a 2 × 2 factorial arrangement of treatments to determine the interaction between a highly saturated free FA supplement (SFFA) and dietary forage NDF (fNDF) content on energy balance and metabolic responses in postpartum cows. Treatment diets were offered fr...
Forty-eight multiparous cows were used in a randomized complete block design experiment with a 2 × 2 factorial arrangement of treatments to determine the interaction between a highly saturated free FA supplement (SFFA) and dietary forage neutral detergent fiber (fNDF) content on production responses and nutrient digestibility of dairy cows in the p...
Effects of stearic acid supplementation on feed intake and metabolic and production responses of dairy cows with a wide range of milk production (32.2 to 64.4 kg/d) were evaluated in a crossover design experiment with a covariate period. Thirty-two multiparous Holstein cows (142 ± 55 d in milk) were assigned randomly within level of milk yield to t...
Energy intake and partitioning are affected by the interaction between diet and the physiological
state. Control of feed intake is complex and involves the integration of multiple signals by brain
feeding centers; dominant control mechanisms vary within a day and across diets and
physiological states. Energy partitioning is affected by insulin conc...
AS COWS MOVE THROUGH LACTATION, their production response to rations change. Incorporating grouping
strategies as you develop rations enables you to meet cows’ needs and avoid the ever present health hassles
associated with rising body condition.
COWS ARE SWITCHED TO THE MAINTENANCE GROUP when they have restored body condition lost in early
lactation, regardless of their milk yield.
Abstract Text:
Effects of forage particle length on apparent ruminal synthesis and post-ruminal supply of thiamin and vitamin B12 were evaluated in two experiments. Alfalfa and orchardgrass were harvested and ensiled at two theoretical lengths of cut: 19-mm (long cut, LC) or 10-mm (short cut, SC). Within a forage type, rations containing silages...
Abstract Text:
The relationship between hepatic acetyl CoA concentration (Ac-CoA) and dry matter intake (DMI) was determined using 28 multiparous Holstein cows; 14 were early-postpartum (PP; 12.6 ± 3.8 DIM) and 14 were late-lactation cows (LL; 271 ± 29.6 DIM). Cows were fed once daily and DMI was determined for the first 4 h after feeding. Liver...
Abstract Text:
Our objective was to evaluate propylene glycol (PG) and glycerol (G) as treatments for ketosis. Two experiments lasting 4 d each were conducted in which cows received one bolus infusion per day. All data were analyzed by ANOVA. Experiment 1 used 6 ruminally-cannulated cows (28 ± 7 DIM) randomly assigned to 300 ml infusions of PG or...
Abstract Text:
Effects of culture pH and corn oil (CO) concentration on NDF digestibility (NDFD) and biohydrogenation (BH) of unsaturated fatty acids (FA) in batch culture were evaluated in a 2x3 factorial design. Cultures (4/treatment/time point) included alfalfa hay plus increasing concentrations of CO (0, 1, 2% DM) incubated at culture pH 5.8...
Abstract Text:
Forty-eight multiparous cows were used in a randomized complete block design experiment with a 2x2 factorial arrangement of treatments. Treatment diets were offered from 1 to 29 d postpartum and contained 20% or 26% forage NDF (fNDF) and 0% or 2% saturated free fatty acid supplement (Energy Booster 100; FAT). The 2% FAT treatment i...
Abstract Text:
Mechanisms controlling feed intake are dependent upon the interaction between diet and physiological state of animals. Physiological state is affected by age, pregnancy, lactation, and adiposity and is characterized by differences in insulin sensitivity of tissues and plasma concentrations of insulin, growth hormone, and leptin. Th...
Abstract Text:
Our objective was to evaluate effects of propionic acid (P) and glycerol (G) on dry matter intake (DMI) and feeding behavior for cows in the immediate postpartum period. We hypothesized that propionic acid will decrease DMI and meal size compared to glycerol because of differences in their hepatic metabolism. Isoenergetic infusions...
Abstract Text:
The objective of this experiment was to evaluate the effects of feeding lactating cows diets differing in starch fermentability twice per day on dry matter intake (DMI), total-tract neutral detergent fiber (NDF) digestibility, and milk fat concentration. Feeding highly fermentable starch sources to ruminants is expected to increase...