Concentrate Allocation Strategy and Precision Feeding in Lactating Dairy Cows
Restricted (Penn State Only)
- Author:
- Ferreira Martins, Leoni
- Graduate Program:
- Animal Science
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- December 16, 2024
- Committee Members:
- Al Rotz, Outside Unit & Field Member
Alexander Hristov, Chair & Dissertation Advisor
Lisa Holden, Major Field Member
Alex Bach, Special Member
Kevin Harvatine, Major Field Member
Ramesh Ramachandran, Program Head/Chair - Keywords:
- amino acids
automatic feeding system
energy
enteric methane
feeding method
milk production
nitrogen
nutrients
precision feeding
rumen - Abstract:
- The objective was to investigate whether concentrate allocation strategy, frequency of concentrate feeding, and individualized concentrate feeding would affect lactational performance, nutrient use efficiency, and enteric CH4 emissions in dairy cows across different stages of lactation. A series of 3 experiments were conducted at The Pennsylvania State University’s Dairy and Research Center. The hypothesis was that feeding concentrates at higher frequencies throughout the day, tailored to individual animal requirements, would improve nutrient use efficiency, decrease enteric CH4 emission intensity, and increase or maintain lactational performance of lactating cows compared with feeding a total mixed ration (TMR). These outcomes were anticipated to result from improved precision nutrition at the individual animal level and a more consistent supply of substrates for ruminal fermentation due to changes in feeding behavior, such as increased meal frequency. The first experiment (Chapter 3) investigated separate offering of feed ingredients (SF) and frequency of concentrate feeding versus offering a TMR on lactational performance, ruminal fermentation, enteric CH4 emissions, nutrient digestibility, and N use efficiency in mid-lactation dairy cows. Twenty-four Holstein cows (12 primi- and 12 multiparous) averaging (± SD) 141 ± 35 days-in-milk at the beginning of the study were used in a replicated 3 × 3 Latin square design experiment. Treatments were: 1) basal diet fed ad libitum as TMR; 2) basal diet fed as SF with forages fed ad libitum and concentrates fed 3 times/d (SF×3); or 3) basal diet fed as SF with forages fed ad libitum and concentrates fed 6 times/d (SF×6). Lactational performance was not affected by treatments, but SF improved feed and N use efficiencies by decreasing feed intake in dairy cows. Additionally, enteric CH4 emissions were decreased by up to 10% with SF compared with TMR. Concentrates were fed manually at 3 and 6 times/day, and the frequency of concentrate feeding did not affect lactational performance and ruminal fermentation variables. This experiment demonstrated that feeding concentrates separately may affect feeding behavior and regulate DMI at the level of a meal. The second experiment (Chapter 4) investigated the effects of SF of a partial mixed ration (PMR) and concentrate premixes (CMix) delivered at fixed or variable amounts using an automatic feeding system (AFS) on lactational performance, enteric CH4 emissions, ruminal fermentation, digestibility of nutrients, and N excretion in lactating dairy cows. Forty-eight primi- and multiparous Holstein cows averaging 91 ± 26 DIM at the beginning of the study were enrolled in a 17-wk randomized complete block design experiment. Treatments were: 1) CON – diet fed ad libitum as TMR; 2) SFF – SF with ad libitum PMR and fixed amounts of CMix using an AFS; and 3) SFV – SF with variable amounts of CMix calculated by a concentrate allocation algorithm and fed using AFS based on individual cow requirements of NEL and MP. Separate offering of fixed amounts of concentrates (SFF) decreased urinary N excretion while maintaining MY and ECM in early- to mid-lactation dairy cows. However, SFV decreased lactational performance and increased CH4 intensity compared with CON. This was likely due to algorithm overfitting and poor generalization in predicting concentrate intake to meet cows’ requirements. This study provided evidence that the allocation of 100% of concentrates in an AFS stimulated competition and disrupted the circadian rhythm of the cows. The third experiment (Chapter 5) investigated the effects of feeding restricted amounts of concentrate in the AFS and individualized concentrate feeding on the lactational performance, chewing activity, enteric CH4 emissions, ruminal fermentation, digestibility of nutrients, and nutrient use efficiency in lactating dairy cows. Forty-eight Holstein multiparous cows averaging (± SD) 200 ± 55 DIM at the beginning of the study were used in 12-wk randomized complete block design experiment. Cows within blocks were randomly assigned to 1 of 2 treatments: 1) CON – ad libitum TMR; 2) PF – ad libitum PMR formulated to meet NEL and AA requirements of a multiparous cow producing 25 kg/d ECM, and 30 to 60% of total concentrates delivered in an AFS based on individual cow NEL and AA requirements estimated using NASEM (2021). Treatments did not affect milk or milk component yields. Milk fat content tended to be decreased whereas milk true protein and lactose contents were increased in PF compared with CON. Eating time was increased by 32 min in PF compared with CON, whereas ruminating time was not affected by treatments in that study. Enteric CH4 emissions were not affected by the individualized concentrate feeding strategy. Overall, feeding concentrates separately from the forages and based on individual cow requirements decreased the excess of nutrients supply while enhancing the concentration of milk components and the efficiency of AA use in mid- to late-lactation dairy cows. Overall, separate feeding of forages and concentrates did not affect lactational performance but increased feed and N use efficiencies in lactating dairy cows. Feeding concentrates more frequently (≥ 6 times/d) promoted similar ruminal fermentation effects as feeding a TMR. Feeding variable amounts of concentrates calculated using an algorithm based on individual NEL and MP balances negatively affected lactational performance and increased CH4 emission intensity, likely because of algorithm overfitting and poor generalization. However, using adjustment factors to feed concentrates separately from the forages and based on individual cow NEL and AA requirements enhanced the efficiency of AA use in mid- to late-lactation dairy cows. Feeding concentrates separately from the forages based on individual cow requirements did not enhance precision nutrition, considering NRC (2001) or NASEM (2021) requirement models, but it enhanced the balance of nutrients and decreased nutrient excretion compared with feeding a TMR.