Effect of feeding an immune modulator to multiparous Holstein cows during the dry period and early lactation on health, milk and reproductive performance

Application of type I and II error analysis to support economic decision-making of using an immunomodulator feed additive

The use of the immunomodulator OmniGen- AF® (OMN) feed supplement, where the response in milk yield, health, and reproduction is uncertain, allows for an application of type I (use the product when it is not profitable) and type II (do not use the product when it is profitable) analysis to aid decision making regarding its profitability. This study applies a type I and II error analysis to quantify the economic risk of investing in OMN feed supplementation using data from a controlled study and a field data set collected on dairy farms. Four prediction models were applied considering the expected value and standard deviation of the response in milk yield; milk and health; milk and reproduction; milk, health, and reproduction. Uncertainty in the milk response was modeled following a normal distribution with mean 0.15 kg/cow/d and standard deviation 0.81 kg/cow/d. This distribution was left-truncated at 0 kg, which resulted in a mean (expected) response of 0.7 kg/cow/d. Based on the field data set, the reduction in health costs and reproduction were estimated at $0.086 and $0.33/cow/day. All 3 responses were assumed to be present or not in the first 90 DIM. The increase in milk yields necessary to pay for the OMN supplementation considering a response in milk yield only, milk and health, milk and reproduction, and milk, health, and reproduction were 0.45, 0.19, -0.56, and -0.82 kg/cow/d respectively. The break-even OMN cost per cow per day when considering the increases in milk yield, milk and health, and milk and reproduction, milk, health, and reproduction were $0.23, $0.31, $0.56, and $0.65 respectively. Production responses resulted in costs exceeding revenue with a type I error cost of $2.62 for milk and $0.47 for milk and health response for the broke even. There was no type I error cost associated when considering the responses in milk and reproduction, and the combination of milk, health and reproduction which implies that there is no risk of using OMN when it is not profitable ( = the product is profitable for certain). Type II costs were associated with returns that are unrealized because of failing to use OMN when it is profitable with an opportunity cost of $9.92, $15.53, $37.23, and $45.08 per cow per day for the responses in milk yield; milk and health; milk and reproduction; and milk, health, and reproduction respectively. We concluded that a type I and II error analysis applied to the use of the OMN feed additive provided additional insights beyond a break-even analysis to support economic decision-making when the response on dairy farms is uncertain. The type I and II error analysis can aid in decision-making process to evaluate the adoption of a new technology.

The physiological dissimilarities of Holstein dairy cows with different milk yields

BACKGROUND

Even if breed, parity, dietary and environmental management are same, dairy cows still have notable differences in milk yield that may be underpinned by physiologic differences.

OBJECTIVES

This study aimed to investigate the physiological dissimilarities of dairy cows with different milk yields.

METHODS

Thirty cows were sorted into high milk-yielding cows (group H: 58.93±2.31 kg/day), moderate milk-yielding cows (group M: 44.99±0.54 kg/day), and low milk-yielding cows (group L: 24.99±6.83 kg/day) according to milk yield. Blood was collected and serum parameters were assessed. Rumen fluid was collected for the evaluation of rumen fermentation parameters (RFPs) and bacterial community composition (BCC).

RESULTS

Serum prolactin, growth hormone, glutathione peroxidase, immunoglobulin A and non-esterified fatty acid had a significantly positive correlation with milk yield (p < 0.05), whereas serum glucagon and total antioxidant capacity had a significantly negative correlation with milk yield (p < 0.05). The concentration of valeric acid and the ratio of acetic acid to propionic acid in the rumen fluid in group H was significantly lower than that in group L (p < 0.05). The concentration of acetic acid and butyric acid in group H was significantly lower than that in groups M and L (p < 0.05). The relative abundances of Ruminococcaceae_NK4A214_group, Prevotella_1, Rikenellaceae_RC9_gut_group, Christensenellaceae_R-7_group, Muribaculaceae, and Ruminococcus_2 were negatively correlated with milk yield, whereas the relative abundance of Succinivibrionaceae_UCG-001, Lachnospiraceae_NK3A20_group, Shuttleworthia and Dialister were positively correlated with milk yield (p < 0.05).

CONCLUSIONS

This study indicates that dairy cows with different milk yields have clear divergence in serum indicators, RFPs, BCC and rumen microbial metabolism.