Animal Science

Whole-farm nutrient mass balances (NMB) can assist producers in evaluation and monitoring the nutrient status of dairy farms over time. Most of the previous studies that report NMB for dairy farms were conducted over 1 to 3 yr. In this study, annual N, P, and K mass balances were assessed on 54 dairy farms in New York State for 4 to 6 yr between 2005 and 2010 with the objectives to (1) document changes in NMB over time and drivers for change, and (2) identify nutrient use efficiency parameters that predicted the potential for improvement in NMB. The study farms varied in size (42 small, 12 medium and large) and management practices. Phosphorus, K, and 2 N balances (N1 without N 2 fixation, and N2 including N 2 fixation) were calculated. In general, farms with high initial NMB levels reduced them over time whereas farms with negative NMB tended to increase their NMB, demonstrating a tendency across all farms to move toward more optimal NMB levels over time. Sixty-three to 76% of farms (depending on the nutrient) reduced their NMB per hectare over the 4 to 6 yr, and 55 to 61% of these farms were able to do so while increasing milk production per cow. Across all farms, the overall reduction in NMB per hectare averaged −22 kg of N/ha for N1 (29% reduction), −16 kg of N/ha for N2 (15% reduction), −4 kg of P/ha (36% reduction), and −10 kg of K/ha (29% reduction). Change in feed imports was the most important driver for change in N and P balances across farms, whereas adjustments in both feed and fertilizer imports affected the K balances. Key predictors of potential areas for improvement in NMB over time include total nutrient imports, feed imports, animal density, percentage of farm-produced feed and nutrients, and feed nutrient use efficiency. Overall, this study highlights the opportunities of an adaptive management approach that includes NMB assessments to evaluate and monitor changes in nutrient use efficiency and cost-efficiency over time.

The long-term sustainability of dairy farms depends on their ability to be profitable while limiting their environmental footprint. The development and implementation of tools and policies that address nitrogen (N), phosphorus (P) and potassium (K) imbalances before they become extreme are essential to the long-term sustainability of dairy farming. At the 2011 Cornell Nutrition Conference, initial data were presented showing that whole-farm nutrient mass balance (NMB) assessments can be used to identify management alternatives that enhance nutrient use efficiency and farm profitability (Ketterings et al, 2011). A NMB approach allows farmers to set targets and then choose the range of practices and approaches to meet goals over time, recognizing that each farm is unique. Case study farms clearly illustrated the potential for large gains in nutrient use efficiency when monitoring of progress becomes part of the package of best management practices, and when producers have complete con...

Animal Nutrition is a required course in animal science curriculums nationwide. Typical of required courses, the class is diverse in previous academic and animal experience. The objective of this research was to gather information about accurate student performance predictors to improve advising and course design. Data from 443 students, representing four semesters (Fall 2007-2010) of Animal Nutrition students, were statistically analyzed to determine predictive relationships between SAT scores, residency, transfer status, animal experience, major, gender, grade in a recommended Cornell general chemistry prerequisite (Cornell Chem) and performance in an introductory animal nutrition course (Animal Nutrition; Cornell University). In addition, an optional survey was administered to the 2010 Animal Nutrition class. In the survey, 27% of students self-identified animal experience level and 48% of transfers identified transfer status as influencers of their grade. Transfer status, residency, SAT scores, gender and grade in Cornell Chem were identified as significant predictors of performance in Animal Nutrition. The highest correlation for a predictor was Cornell Chem grade; completion of Chem was associated with significantly higher Animal Nutrition grades. Gaining information about accurate student performance predictors can assist advisors in making course recommendations as well as instructors in designing the course to best enable corporate learning regardless of the diversity in student preparation.

A whole-farm nutrient mass balance (NMB) is a useful measure of the nutrient status of a dairy farm. Research is needed to define and determine a feasible NMB range for dairy farm systems in New York State (NY). The objectives of this study were to (1) document the distribution of N, P, and K mass balances of 102 NY dairy farms (including 75 small, 15 medium, and 12 large farms); (2) establish initial NMB benchmarks based on what 75% of the farms achieved; (3) determine the maximum animal density that allows an example NY dairy farm to balance cow P excretions and crop P removal without exporting crops or manure; and (4) identify opportunities to improve NMB over time. Nutrient mass balances of the 102 farms ranged from −39 to 237 kg of N/ha for N without including N 2 fixation (N1), from −14 to 259 kg of N/ha when N 2 fixation was included (N2), from −7 to 51 kg of P/ha, and from −46 to 148 kg of K/ha. Seventy-five percent of the farms were operating at NMB less than 118 kg of N/ha for N1, 146 kg of N/ha for N2, 13 kg of P/ha, and 41 kg of K/ha (75% benchmarks). Farms with the highest nutrient use efficiencies (lowest NMB per unit of milk produced) operated with less than 8.8 kg of N/Mg of milk for N1, 11.8 kg of N/Mg of milk for N2, 1.1 kg of P/Mg of milk, and 3.0 kg of K/Mg of milk. The biggest contributor to the NMB was the amount of imported nutrients, primarily feed purchases. The example farm assessment (assuming no export of crops or manure) suggested that, when 70% of the feed is produced on the farm and P in feed rations does not exceed 4 g of P/kg of DM, cow P excretion and crop P removal were balanced at a maximum animal density of 2.4 animal units (AU)/ha (~0.97 AU/acre). Dairy farms operating with animal densities <2.4 AU/ha typically had NMB below the 75% benchmark, whereas most dairies with more than 2.4 AU/ha needed to export manure or crops to meet the 75% benchmark. Opportunities to reduce NMB on many farms, independent of size and without changes in animal density, are possible by more tightly managing fertilizer and feed imports, increasing the percentage of farm-produced nutrients, implementing precision feeding, and exporting crops or manure.

The whole-farm nutrient mass balance (NMB) is an adaptive management tool that can be used to identify areas for improvement in nutrient management and to monitor progress over time. The objectives of this study were to (1) evaluate the trends of nitrogen and phosphorus mass balances of 27 New York State dairy farms over 6 to 10 yr, (2) identify specific management changes made by 4 case study farms that improved NMB over time by shifting NMB up or down depending on the initial NMB, and (3) evaluate the potential of key indicators to identify opportunities for improvement in NMB. During the study period, milk price fluctuated whereas costs associated with feed and fertilizer increased substantially. Of the 27 farms, 67 to 74% (depending on the nutrient) decreased NMB per hectare over time, whereas 63 to 67% decreased NMB per megagram of milk over time. In general, changes in NMB were directionally correct, with 43 to 56% of farms operating in the optimum operational zone (with both ...

Ferulic acid (FRA), a phenolic compound with antioxidant and anticancer activities, naturally occurs in plants as a lignin precursor. Many veins of research have been devoted to releasing FRA from the lignin complex to improve digestibility of ruminant feeds. Thus, the objective of this research was to investigate the transfer of a given dosage of the free form of FRA into the milk of dairy cattle. Six mid-to late-lactation Holstein cows at the Cornell Research Farm (Harford, NY) were given 14-d adaptation to diet and stall position. Ad libitum access to a total mixed ration based on haylage and maize silage (31.1% neutral detergent fiber containing 5.52 mg of FRA/g) was provided during the study. A crossover design was implemented so that each cow alternated weekly between FRA-dosed and control. On d 1, jugular cannulas and urine catheters were placed in all cows. On d 2, FRA-dosed cows received a single dosage of 150 g of pure FRA powder at 0830 h via their fistula (n = 4) or a balling gun for nonfistulated cows (n = 2). Plasma, urine, feces, feed, orts, milk, and rumen fluid were sampled intensively for the next 36 h and analyzed for FRA concentration. On d 8, the cows crossed over and the experiment was repeated. When compared with the control, FRA administration did not have an effect on dry matter intake, milk yield, milk fat yield, milk protein yield, somatic cell count, or neutral detergent fiber content of orts and feces. The concentration of FRA in the feces did not change as a result of FRA dosage. As expected, FRA concentration increased dramatically upon FRA dosage and decreased over time until returning to basal levels in rumen fluid (4 h after dosage), plasma (5.5 h after dosage), urine (10 h after dosage), and milk (14 h after dosage). Baseline values for FRA in urine and rumen fluid were variable among cows and had an effect on FRA concentration in FRA-dosed cows. From this study, it is observed that orally ingested FRA can be transported into the milk and that the physiological transfer of FRA occurs from rumen to milk within 6.5 h or the first milking after dosage. Ferulic acid may affect the functionality of milk due to its antioxidant, anticancer, and antibacterial activities. Future research will be required to elucidate whether FRA in milk is bioavailable and bioactive, and to evaluate the complete sensory and microbiological effects of increased FRA and FRA degradation products in milk.

States in the Chesapeake Bay watershed (CBW) are required to reduce nitrogen (N) and phosphorus (P) loads from agriculture to achieve water quality goals for 2025. Assessing nutrient mass balances (NMBs) on farms over multiple years allows for evaluation of trends in nutrient accumulation and potential losses in geographic regions. Between 2004 and 2013, 570 NMBs were conducted for 189 dairy farms in New York, including 91 farms (293 NMBs) in the Upper Susquehanna watershed (USW), headwaters of the CBW. The average NMBs per hectare and per megagram of milk were lower for farms in the USW than statewide. Data showed a decline in NMBs per hectare over 10 years that ranged from 29% to 42% (statewide) and from 29% to 51% (for the USW dairies), depending on the nutrient, while milk production remained constant in both regions. Reductions in NMBs resulted primarily from reductions in nutrient imports, particularly through feed management. These source reductions reflect increased efficiency of production and reduced risk of N and P loss to the CBW. Extrapolation of comparisons in NMBs between 2004 and 2013 suggest that dairies in the USW reduced total N and P imports by 30% and 20%, respectively, contributing to a 29% to 50% decrease in total N pool and 51% decrease in P pool. We conclude that USW dairy farms can deliver up to 49% of their 2013 N pool and up to 72% of their 2013 P pool at the edge of the farms (their NMB) and still meet the total maximum daily load (TMDL) for N and P set for 2025 for New York agriculture. This study illustrates that significant nutrient source reduction can be obtained by implementing nutrient conservation practices, such as precision feeding and fertilizer management, combined with annual assessment of whole farm balances. Such a reduction in nutrient imports onto farms results in a reduction of the pool of nutrients available for accumulation in the soil or direct loss to water bodies and the atmosphere.

A whole-farm nutrient mass balance (NMB) is a useful measure of the nutrient status of a dairy farm. Research is needed to define and determine a feasible NMB range for dairy farm systems in New York State (NY). The objectives of this study were to (1) document the distribution of N, P, and K mass balances of 102 NY dairy farms (including 75 small, 15 medium, and 12 large farms); (2) establish initial NMB benchmarks based on what 75% of the farms achieved; (3) determine the maximum animal density that allows an example NY dairy farm to balance cow P excretions and crop P removal without exporting crops or manure; and (4) identify opportunities to improve NMB over time. Nutrient mass balances of the 102 farms ranged from −39 to 237 kg of N/ha for N without including N 2 fixation (N1), from −14 to 259 kg of N/ha when N 2 fixation was included (N2), from −7 to 51 kg of P/ha, and from −46 to 148 kg of K/ha. Seventy-five percent of the farms were operating at NMB less than 118 kg of N/ha for N1, 146 kg of N/ha for N2, 13 kg of P/ha, and 41 kg of K/ha (75% benchmarks). Farms with the highest nutrient use efficiencies (lowest NMB per unit of milk produced) operated with less than 8.8 kg of N/Mg of milk for N1, 11.8 kg of N/Mg of milk for N2, 1.1 kg of P/Mg of milk, and 3.0 kg of K/Mg of milk. The biggest contributor to the NMB was the amount of imported nutrients, primarily feed purchases. The example farm assessment (assuming no export of crops or manure) suggested that, when 70% of the feed is produced on the farm and P in feed rations does not exceed 4 g of P/kg of DM, cow P excretion and crop P removal were balanced at a maximum animal density of 2.4 animal units (AU)/ha (~0.97 AU/acre). Dairy farms operating with animal densities <2.4 AU/ha typically had NMB below the 75% benchmark, whereas most dairies with more than 2.4 AU/ha needed to export manure or crops to meet the 75% benchmark. Opportunities to reduce NMB on many farms, independent of size and without changes in animal density, are possible by more tightly managing fertilizer and feed imports, increasing the percentage of farm-produced nutrients, implementing precision feeding, and exporting crops or manure.

States in the Chesapeake Bay watershed (CBW) are required to reduce nitrogen (N) and phosphorus (P) loads from agriculture to achieve water quality goals for 2025. Assessing nutrient mass balances (NMBs) on farms over multiple years allows for evaluation of trends in nutrient accumulation and potential losses in geographic regions. Between 2004 and 2013, 570 NMBs were conducted for 189 dairy farms in New York, including 91 farms (293 NMBs) in the Upper Susquehanna watershed (USW), headwaters of the CBW. The average NMBs per hectare and per megagram of milk were lower for farms in the USW than statewide. Data showed a decline in NMBs per hectare over 10 years that ranged from 29% to 42% (statewide) and from 29% to 51% (for the USW dairies), depending on the nutrient, while milk production remained constant in both regions. Reductions in NMBs resulted primarily from reductions in nutrient imports, particularly through feed management. These source reductions reflect increased efficiency of production and reduced risk of N and P loss to the CBW. Extrapolation of comparisons in NMBs between 2004 and 2013 suggest that dairies in the USW reduced total N and P imports by 30% and 20%, respectively, contributing to a 29% to 50% decrease in total N pool and 51% decrease in P pool. We conclude that USW dairy farms can deliver up to 49% of their 2013 N pool and up to 72% of their 2013 P pool at the edge of the farms (their NMB) and still meet the total maximum daily load (TMDL) for N and P set for 2025 for New York agriculture. This study illustrates that significant nutrient source reduction can be obtained by implementing nutrient conservation practices, such as precision feeding and fertilizer management, combined with annual assessment of whole farm balances. Such a reduction in nutrient imports onto farms results in a reduction of the pool of nutrients available for accumulation in the soil or direct loss to water bodies and the atmosphere.

Ferulic acid (FRA), a phenolic compound with antioxidant and anticancer activities, naturally occurs in plants as a lignin precursor. Many veins of research have been devoted to releasing FRA from the lignin complex to improve digestibility of ruminant feeds. Thus, the objective of this research was to investigate the transfer of a given dosage of the free form of FRA into the milk of dairy cattle. Six mid-to late-lactation Holstein cows at the Cornell Research Farm (Harford, NY) were given 14-d adaptation to diet and stall position. Ad libitum access to a total mixed ration based on haylage and maize silage (31.1% neutral detergent fiber containing 5.52 mg of FRA/g) was provided during the study. A crossover design was implemented so that each cow alternated weekly between FRA-dosed and control. On d 1, jugular cannulas and urine catheters were placed in all cows. On d 2, FRA-dosed cows received a single dosage of 150 g of pure FRA powder at 0830 h via their fistula (n = 4) or a balling gun for nonfistulated cows (n = 2). Plasma, urine, feces, feed, orts, milk, and rumen fluid were sampled intensively for the next 36 h and analyzed for FRA concentration. On d 8, the cows crossed over and the experiment was repeated. When compared with the control, FRA administration did not have an effect on dry matter intake, milk yield, milk fat yield, milk protein yield, somatic cell count, or neutral detergent fiber content of orts and feces. The concentration of FRA in the feces did not change as a result of FRA dosage. As expected, FRA concentration increased dramatically upon FRA dosage and decreased over time until returning to basal levels in rumen fluid (4 h after dosage), plasma (5.5 h after dosage), urine (10 h after dosage), and milk (14 h after dosage). Baseline values for FRA in urine and rumen fluid were variable among cows and had an effect on FRA concentration in FRA-dosed cows. From this study, it is observed that orally ingested FRA can be transported into the milk and that the physiological transfer of FRA occurs from rumen to milk within 6.5 h or the first milking after dosage. Ferulic acid may affect the functionality of milk due to its antioxidant, anticancer, and antibacterial activities. Future research will be required to elucidate whether FRA in milk is bioavailable and bioactive, and to evaluate the complete sensory and microbiological effects of increased FRA and FRA degradation products in milk.

The long-term sustainability of dairy farms depends on their ability to be profitable while limiting their environmental footprint. The development and implementation of tools and policies that address nitrogen (N), phosphorus (P) and potassium (K) imbalances before they become extreme are essential to the long-term sustainability of dairy farming. At the 2011 Cornell Nutrition Conference, initial data were presented showing that whole-farm nutrient mass balance (NMB) assessments can be used to identify management alternatives that enhance nutrient use efficiency and farm profitability (Ketterings et al, 2011). A NMB approach allows farmers to set targets and then choose the range of practices and approaches to meet goals over time, recognizing that each farm is unique. Case study farms clearly illustrated the potential for large gains in nutrient use efficiency when monitoring of progress becomes part of the package of best management practices, and when producers have complete control of where to make changes in their individual operations. For these reasons, we strongly encouraged dairy producers to participate in an annual NMB assessment and we also urged nutritionists to get involved as imported feed is frequently the single largest contributor to nutrient imports and hence NMBs of dairy farms.

was born on May 12, 1983 in Peoria, Illinois to Stephen and Tamia Schotthofer. She and her sisters, Melissa and Stephanie, grew up on a minifarm, surrounded by horses, sheep, chickens, dogs and cats; summertime was filled with putting up hay, selling the family"s garden produce on her grandma"s gift shop porch and preparing for the 4-H fair. At the age of 15, her family relocated to Cochrane, Wisconsin to pursue their dream of dairy farming full-time. Due to poor milk prices at the time, the family altered their goals to dairy sheep production, and Melanie worked alongside her parents and sisters to expand a flock of 37 meat sheep into a 450+ ewe flock with dairy sheep genetics. On weekends, she helped the family direct market the lamb produced at the St. Paul Farmer"s Market. Though she became proficient at working with sheep, her interests remained in the sphere of dairying, whether with sheep or cows. After finishing high school at Cochrane-Fountain City in 2001, she attended the University of Wisconsin-Madison on scholarship. While there, she developed a love for science writing. In 2005, she graduated from UW-Madison with a double major in Animal Sciences and Life Science Communications, with emphases in Business. Melanie came to Cornell University to earn a Master of Science degree in Sheep Nutrition under the direction of Dr. Michael Thonney. In August of 2007, she then began a PhD with Dr. Debbie Cherney in the area of Ruminant Nutrition, incorporating aspects of Food Science to produce the research in this dissertation. Throughout her studies, Melanie discovered a joy in teaching animal science, which led her to participate in the Cornell Center for Teaching Excellence"s Future Faculty Teaching Certificate program. This culminated in her first publication in the scholarship of teaching and learning, also included in this dissertation. In June of 2007, she married Fernando Soberon and they were blessed with two children,

Colostrum has long been valued as critical to new¬ born calf health, but its potential impact on the nutritional programming of the calf and consequently, her lifetime performance in milk production and health, are now areas of active research. New levels of importance and value are being attributed to colostrum, as scientists work to better understand the mechanisms and regulation of epigenetics, the influences of non-nutritional components of colostrum, and the impact of timely colostrum nutrition. Many of these benefits of colostrum were once attributed to passive transfer, but epigenetics and nutritional programming have revealed that there is much more in colostrum than IgG. Relaxin, leptin, insulin, IGF-I, IGF-II, prolactin, and lactoferrin are some of the nutritional and non-nutritional factors in colostrum that have a direct and indirect effect on the development and long-term gene expression of offspring. Researchers have shown that calves that received more colostrum at birth have higher av¬ erage daily gains improved feed efficiency, higher dry matter intakes post-weaning, reduced time to conception and first calving, increased milk production during 2 lactations, and an increased survivability through second lactation.

After parturition, the somatotropic axis of the dairy cow is uncoupled, partly because of reduced concentration of liver-specific GH receptor (GHR) 1A. Estradiol-17 β(E2) concentrations increase at parturition and E2 upregulates suppressors of cytokine signaling-2 (SOCS-2) mRNA expression, potentially inhibiting GH signaling. Therefore, we hypothesized that SOCS-2 mRNA is upregulated after parturition. Multiparous Holstein cows (n = 18) were dried off 45 d before expected parturition and fed diets to meet nutrient requirements at ad libitum or limited dry matter intake during the dry period. All cows were fed the same diet ad libitum from calving until 4 wk after parturition. Blood samples were collected weekly and more frequently near parturition. Liver biopsies obtained at – 21, – 7, 2, and 28 d relative to parturition were assessed for SOCS-2 and GHR 1A mRNA by quantitative real-time reverse-transcription PCR. The relative amount of SOCS-2 mRNA increased after parturition with both treatments and was greater on d 2 for cows limit-fed during the dry period compared with cows fed at ad libitum dry matter intake. Plasma E2 concentrations increased on d – 13, – 5 and 1 relative to parturition and the increases were greater in limit-fed cows. Plasma GH concentration was greater for limit-fed cows and increased after parturition in all cows. The amount of GHR 1A mRNA did not differ between diets but decreased on d 2. In addition to reduced GHR 1A, increased SOCS-2 mRNA after parturition, perhaps because of increased E2, may further uncouple GH signaling in the liver of the transition dairy cow.

Limit-feeding dry cows a high-energy diet may enable adequate energy intake to be sustained as parturition approaches, thus reducing the extent of negative energy balance after parturition. Our objective was to evaluate the effect of dry period feeding strategy on plasma concentrations of hormones and metabolites that reflect energy status. Multiparous Holstein cows (n = 18) were dried off 45 d before expected parturition, paired by expected calving date, parity, and previous lactation milk yield, and randomly assigned to 1 of 2 dry-period diets formulated to meet nutrient requirements at ad libitum or limited intakes. All cows were fed the same diet for ad libitum intake after parturition. Prepartum dry matter intake (DMI) for limit-fed cows was 9.4 kg/d vs. 13.7 kg/d for cows fed ad libitum. During the dry period, limit-fed cows consumed enough feed to meet calculated energy requirements, and ad libitum-fed cows were in positive calculated net energy for lactation (NEL) balance (0.02 vs. 6.37 Mcal/d, respectively). After parturition, milk yield, milk protein concentration, DMI, body condition score, and body weight were not affected by the prepartum treatments. Cows limit fed during the dry period had a less-negative calculated energy balance during wk 1 postpartum. Milk fat concentration and yield were greater for the ad libitum treatment during wk 1 but were lower in wk 2 and 3 postpartum. Plasma insulin and glucose concentrations decreased after calving. Plasma insulin concentration was greater in ad libitum-fed cows on d –2 relative to calving, but did not differ by dietary treatment at other times. Plasma glucose concentrations were lower before and after parturition for cows limit-fed during the dry period. Plasma nonesterified fatty acid concentrations peaked after parturition on d 1 and 4 for the limit-fed and ad libitum treatments, respectively, and were greater for limit-fed cows on d –18, –9, –5, and –2. Plasma tumor necrosis factor- concentrations did not differ by treatment in either the pre- or postpartum period, but tended to decrease after parturition. Apart from a reduction in body energy loss in the first week after calving, limit feeding a higher NEL diet during the dry period had little effect on intake and milk production during the first month of lactation.

The lactating mammary gland synthesizes large amounts of triglyceride from fatty acids derived from the blood and from de novo lipogenesis. The latter is significantly increased at parturition and decreased when additional dietary fatty acids become available. To begin to understand the molecular regulation of de novo lipogenesis, we tested the hypothesis that the transcription factor sterol regulatory element binding factor (SREBF)-1c is a primary regulator of this system. Expression of Srebf1c mRNA and six of its known target genes increased ≥2.5-fold at parturition. However, Srebf1c-null mice showed only minor deficiencies in lipid synthesis during lactation, possibly due to compensation by Srebf1a expression. To abrogate the function of both isoforms of Srebf1, we bred mice to obtain a mammary epithelial cell-specific deletion of SREBF cleavage-activating protein (SCAP), the SREBF escort protein. These dams showed a significant lactation deficiency, and expression of mRNA for fa...