About

Kevin J. Harvatine is the C. Lee Rumberger Chair in Agricultural Sciences at the Pennsylvania State University. His role involves advancing research and education in agricultural sciences, with a focus on animal science. As a faculty member within the Department of Animal Science, he contributes to the understanding and management of animals for agriculture and companionship. His work is integral to the department's mission of scientific, business, and technical management of animals.

Research topics

• Chemistry
• Food science
• Biology
• Animal science
• Biochemistry
• Medicine
• Internal medicine
• Physics
• Organic chemistry
• Endocrinology
• Mathematics
• Thermodynamics
• Nanotechnology
• Environmental science
• Chromatography
• Mechanics
• Materials science

Selected publications

• Direct Comparison of 18 Carbon n–3 and n–6 Fatty Acids at Equal Levels in an Oil Blend on Tissue Enrichment of Long-Chain Polyunsaturated Fatty Acid in Broiler Chickens

  Journal of Nutrition · 2023 · 8 citations

  Senior authorCorresponding
  • Food science
  • Chemistry
  • Biochemistry
  DOI

• Effect of the timing of sodium acetate infusion on the daily rhythms of milk synthesis and plasma metabolites and hormones in Holstein cows

  Journal of Dairy Science · 2022 · 7 citations

  Senior authorCorresponding
  • Animal science
  • Chemistry
  • Internal medicine

  Dairy cows have a daily pattern of feed intake which influences ruminal fermentation and nutrient absorption. Milk synthesis also exhibits a daily rhythm and is altered by the timing of feed availability. Nutrients can regulate physiological rhythms, but it is unclear which specific nutrients affect the rhythms of milk synthesis in the cow. The objective of this study was to determine the effect of the timing of acetate infusion on the daily rhythms of feed intake, milk synthesis, milk fatty acids, plasma insulin and metabolites, and core body temperature. Ten lactating ruminally cannulated Holstein cows (127 ± 24.6 d in milk; mean ± standard deviation) were arranged in a 3 × 3 Latin square design. Treatments were ruminal infusions of 600 g/d of acetate either continuously throughout the day (CON) or over 8 h/d during the day (day treatment, DT; 0900 to 1700 h) or the night (night treatment, NT; 2100 to 0500 h). Experimental periods were 14 d with a 7-d washout between periods. Cows were milked every 6 h during the final 7 d of each experimental period to determine the daily pattern of milk synthesis. Blood samples were taken to represent every 4 h across the day and plasma glucose, insulin, β-hydroxybutyrate, urea nitrogen, and acetate concentration were measured. An intravaginal temperature logger was used to measure core body temperature. Data were analyzed with cosinor-based rhythmometry to test the fit of a cosine function with a period of 24 h and to determine the acrophase (time at peak) and amplitude (peak to mean) of each rhythm. Milk yield fit a daily rhythm for all treatments and DT and NT phase-delayed the rhythm and DT increased the robustness of the rhythm. Milk protein concentration fit a daily rhythm for all treatments and DT increased robustness, whereas NT phase-delayed the rhythm. Plasma acetate concentration also fit a daily rhythm in all treatments. Plasma acetate peaked at ∼1600 h in CON and DT and at 0053 h in NT, reflecting the timing of treatment infusions. There was a daily rhythm in plasma β-hydroxybutyrate that reflected the plasma acetate rhythm. Core body temperature fit a rhythm for all treatments, but the amplitude of the rhythm was smaller than previously observed. In conclusion, the timing of acetate infusion influences peripheral rhythms of milk synthesis and plasma metabolites.

  PublisherOA PDFDOI

• Comparison of Ahiflower oil containing stearidonic acid to a high‐alpha‐linolenic acid flaxseed oil at two levels on tissue omega‐3 enrichment in broilers

  Lipids · 2021 · 16 citations

  Senior authorCorresponding
  • Food science
  • Chemistry
  • Animal science

  Enrichment of broiler meat with very long-chain omega-3 fatty acids (VLCn-3 FA) is of interest because of their beneficial effects on human health. The ability of Ahiflower® (AHI) oil (Buglossoides arvensis), which naturally contains stearidonic acid (SDA), and a high-alpha-linolenic acid (ALA) flaxseed (FLAX) oil to enrich VLCn-3 FA contents in broilers tissues was investigated. Fifty-five Cobb 500 chicks were fed from days 12 to 35 of life either a control (CON) diet that contained 27.9 g/kg soybean oil or AHI or FLAX oils, each individually at 7.5 or 22.5 g/kg of the diet in substitution for soybean oil (all on an as fed basis). Total VLCn-3 FA contents were greater in breast, thigh, liver, adipose tissue, and plasma of all n-3 treatments compared to CON, with the greatest increase observed at the highest level of AHI and FLAX oils (p < 0.001). AHI oil at 7.5 g/kg promoted the most efficient synthesis and deposition of VLCn-3 in broiler tissues measured as deposition of VLCn-3 FA in tissues relative to intake of n3 FA. In conclusion, both ALA and SDA oils increased VLCn-3 FA deposition in tissues, but there were diminishing returns when increasing dietary levels of the oils.

  DOI

• Meta-analysis of the relationship between milk trans-10 C18:1, milk fatty acids &lt;16 C, and milk fat production

  Journal of Dairy Science · 2020 · 38 citations

  Senior authorCorresponding
  • Food science
  • Chemistry
  • Biology

  was -0.503 ± 0.07 (posterior mean ± posterior standard deviation from the Bayesian hierarchical model). A Lin's concordance correlation coefficient of 0.67 suggested good agreement between observations and predictions from the Bayesian hierarchical model, computed only with the model's mean population parameters. There was a linear relationship between milk fat concentration and FA <16 C as a percentage of total FA (intercept = 2.68 ± 0.237 and slope = 0.043 ± 0.011; coefficient of determination = 0.31). The relationship between milk FA <16 C and milk fat concentration is weaker than what has been published, likely because multiple factors can reduce de novo FA without reducing milk fat and the broad range of diets present in the literature.

  DOI

• Effects of high-starch or high-fat diets formulated to be isoenergetic on energy and nitrogen partitioning and utilization in lactating Jersey cows

  Journal of Dairy Science · 2020 · 29 citations

  • Chemistry
  • Animal science
  • Food science

  content, increased partitioning of N toward milk secretion and away from urinary excretion, and may have increased partitioning of energy toward tissue energy deposited as fat.

  DOI

• Night-restricted feeding of dairy cows modifies daily rhythms of feed intake, milk synthesis and plasma metabolites compared with day-restricted feeding

  British Journal Of Nutrition · 2020 · 32 citations

  Senior authorCorresponding
  • Animal science
  • Biology
  • Endocrinology

  The timing of feed intake can alter circadian rhythms of peripheral tissues. Milk synthesis displays a daily rhythm across several species, but the effect of feeding time on these rhythms is poorly characterised. The objective of this experiment was to determine if the time of feed intake modifies the daily patterns of milk synthesis, plasma metabolites and body temperature in dairy cows. Sixteen lactating Holstein dairy cows were randomly assigned to one of the two treatment sequences in a cross-over design with 17 d periods. Treatments included day-restricted feeding (DRF; feed available from 07.00 to 23.00 hours) and night-restricted feeding (NRF; feed available from 19.00 to 11.00 hours). Cows were milked every 6 h on the last 7 d of each period, and blood samples were collected to represent every 4 h over the day. Peak milk yield was shifted from morning in DRF to evening in NRF, while milk fat, protein and lactose concentration peaked in the evening in DRF and the morning in NRF. Plasma glucose, insulin, NEFA and urea nitrogen concentration fit daily rhythms in all treatments. Night feeding increased the amplitude of glucose, insulin and NEFA rhythms and shifted the daily rhythms by 8 to 12 h (P < 0·05). Night feeding also phase-delayed the rhythm of core body temperature and DRF increased its amplitude. Altering the time of feed availability shifts the daily rhythms of milk synthesis and plasma hormone and metabolite concentrations and body temperature, suggesting that these rhythms may be entrained by food intake.

  PublisherOA PDFDOI

• Annual rhythms of milk synthesis in dairy herds in 4 regions of the United States and their relationships to environmental indicators

  Journal of Dairy Science · 2020 · 11 citations

  Senior authorCorresponding
  • Animal science
  • Biology
  • Food science

  The annual rhythms of milk and milk component yields are not well described and are important to dairy management. Recent analysis of federal milk marketing orders in the United States observed that the amplitude and time at peak (acrophase) of the rhythms of milk fat and protein concentration differ among regions, but the rhythms of milk and milk component yields are not well described. Our objective was to determine the annual rhythms of milk and milk component production from 4 US regions at the herd level and examine potential environmental factors entraining these rhythms. Monthly Dairy Herd Improvement Association records of all available herds in Pennsylvania (PA), Minnesota (MN), Texas (TX), and Florida (FL) from the years 2003 to 2016 were obtained from Dairy Records Managements Systems. Milk yield, fat and protein yield, and fat and protein concentration were fit to the linear form of the cosine function with a 12-mo period using a linear mixed effects model. Additionally, the fit of models containing either the cosine function or environmental temperature were compared using an F-test. Milk yield and fat and protein yields and concentrations fit a cosine function in all 4 states, indicating an annual rhythm. The amplitude (peak to mean) of the rhythm of milk yield varied by state and was lower in PA (1.2 kg) and MN (1.2 kg) compared with TX (3.1 kg) and FL (3.3 kg). Fat and protein yields similarly showed greater amplitudes in the southern versus northern states. The amplitudes of the rhythms of fat and protein concentration were opposite by region, with greater amplitudes occurring in MN and PA than in TX and FL. The acrophases of milk yield and milk fat and protein yields and concentrations also varied by state, but all peaked between October and March. An annual rhythm fit the data better than changes in environmental temperature for all responses in all states, except for fat and protein concentrations in FL, which exhibited lower amplitude seasonal rhythms. The yearly pattern of milk yield closely followed the fixed yearly pattern of the day to day changes in day length, whereas the rhythms of milk fat and protein concentrations followed the yearly pattern of absolute day length. Results suggest that the region of the United States in which a herd is located affects their annual rhythms of production, with a greater yearly variation in milk, fat, and protein yields occurring in the southern United States. The consistency of annual rhythms across years and herds allowed development of regression equations to adjust expectations across the year to account for the annual rhythm.

  PublisherOA PDFDOI

• Physical characterization of fatty acid supplements with varying enrichments of palmitic and stearic acid by differential scanning calorimetry

  Journal of Dairy Science · 2020 · 11 citations

  Senior authorCorresponding
  • Chemistry
  • Chromatography
  • Food science

  Saturated fatty acid supplements commonly fed to dairy cows differ in their fatty acid (FA) profile. Some supplements with very high enrichments of palmitic acid (PA) or stearic acid (SA) have been reported to have low total-tract digestibility. Saturated FA have the potential to form crystalline structures at high purity that may affect digestibility. Differential scanning calorimetry (DSC) is a thermal technique commonly used in materials science to measure the change in heat flow as energy is absorbed or released from a sample during heating, and it was used to characterize a series of experimental and commercial fat supplements. Our hypothesis was that products with very high enrichment of either PA or SA would differ in thermal characteristics compared with those that include moderate levels of a second FA because of the formation of secondary crystalline structures, which may contribute to decreased digestibility. First, replicated runs demonstrated low variation in melting temperature (MT) and enthalpy (coefficient of variation <4%). The effect of physical form was evaluated by comparing an initial thermal cycle to a second, successive thermal cycle after samples had resolidified in the test pan. Melting temperature was slightly increased by 1.3°C by the second cycle compared with the first, but there was no change in enthalpy. Next, supplements with 98% SA, 98% PA, and an SA/PA (44%/55%) blend with undetectable levels of unsaturated FA were compared. Melting temperature of the SA/PA mixture was 61.2°C and similar to the expected MT of PA (62.9°C). However, the MT of the high-purity SA and PA were increased to 73.7°C and 67.8°C, respectively, and enthalpy increased by 12.5% compared with the SA/PA blend. An FA stock highly enriched in SA (>98%) had the highest MT, and one moderately enriched in PA (∼85%) that contained 10.1% unsaturated FA had the lowest enthalpy value of all FA supplements and experimental stocks that were characterized. Differential scanning calorimetry may be useful to screen and design supplements with improved physical properties that may be associated with digestibility.

  PublisherOA PDFDOI

• Technical note: Method for improving precision of in-parlor milk meters and adjusting milk weights for stall effects

  Journal of Dairy Science · 2020 · 15 citations

  Senior authorCorresponding
  • Animal science
  • Mathematics
  • Environmental science

  Milk yield is a fundamental observation in most dairy experiments and is commonly determined using integrated milk meters that measure milk weight as the cow is being milked. These meters are heavily used in a harsh environment and often are not regularly calibrated, so calibration errors and mechanical problems may create artificial variation in milk weight data. Additionally, direct calibration by collection of milk in a bucket is difficult and imperfect because the use of the bucket may affect yield recorded by the milk meter. The objective of this work was to define a method to easily check parlor meter precision and adjust milk weight values for variation between individual stalls in a parlor. Because most cows are milked in a different stall at each milking, it has been proposed that stall deviations that represent the fixed effect of stall on milk weight could be statistically determined. Individual milk weights from 14 milkings across 7 d from approximately 200 cows were collected from the Penn State dairy farm, which is equipped with a double-10 herringbone parlor with an Afimilk 2000 milking system (S.A.E. Afikim, Afikim, Israel). Milk yield was measured automatically by in-line flow through milk meters (Afi 200; S.A.E. Afikim). The effect of stall on milk weight was modeled using a mixed model that included the fixed effect of stall and the random effects of day, milking time, and cow. First, stall deviations were calculated as the stall least squares means (LSM) minus the average LSM to identify malfunctioning meters requiring service (e.g., deviation exceeding 1 kg). A correction factor for each stall was then generated by dividing the LSM of each stall by the average LSM. Milk yields were then corrected by multiplying the meter weight value by the correction factor. To determine the effect of the correction, raw and corrected meter values were compared with weight of milk collected in a bucket (n = 3/stall). The corrected values had a 5% greater coefficient of determination than raw meter values (0.89 vs. 0.84) and had a lower average percent difference from the bucket milk weight compared with raw meter values (12.6% vs. 13.5%). The method was then used in 3 experiments with 121, 140, and 683 milk yield observations. In all data sets, correcting milk weights slightly improved model fit and had minimal effect on model term standard errors. However, this validation was completed in a parlor where the method was routinely used to identify stalls requiring service; the effect of stall corrections is expected to be larger in parlors without frequent monitoring. Stall deviations are expected to be due predominantly to calibration of the meter but also could be due to differences in pulsation or other stall-specific factors that result in a change in milk yield. It is important to account for these other sources of milk weight variation that are unrelated to treatment. Modeling the effect of stall is a simple, convenient, and low-cost method to monitor and improve milk meter precision and functionality and can be used to reduce artificial variation and experimental error.

  PublisherOA PDFDOI

Frequent coauthors

• Yun Ying

  University of Pennsylvania

  23 shared

• M. Baldin

  Pennsylvania State University

  17 shared

• I.J. Salfer

  University of Minnesota

  16 shared

• Dale E. Bauman

  University of Vermont

  16 shared

• Yves R. Boisclair

  Universidade do Estado de Santa Catarina

  14 shared

• D.E. Rico

  12 shared

• Natalie L. Urrutia

  Instituto de Investigaciones Agropecuarias

  11 shared

• Robert G. Elkin

  Pennsylvania State University

  11 shared

Education

• B.S.

  Penn State

  2001

• M.S.

  Michigan State University

  2003

• Ph.D.

  Cornell University

  2008

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