ASSOCIATION OF DIETARY NUTRIENT COMPOSITION AND FEED QUALITY WITH MILK PRODUCTION, MILK COMPOSITION, AND FEED EFFICIENCY IN DAIRY CATTLE

Abstract

Background: Optimizing total mixed ration (TMR) formulation, to maximize lactation performance and feed conversion efficiency, continues to be a basic need of high yield dairy herds.

Objective: To investigate the quantitative relationships of different nutrient composition of the diet (Crude Protein (CP), Neutral Detergent Fiber (NDF), Metabolizable Energy (ME)) in relation to Feed Quality Score (FQS) with daily milk yield, milk composition (fat, protein, lactose) and Feed Efficiency (FE) of Holstein-Friesian dairy cows.

Methods: Operational data from 100 lactating dairy cows N was taken from the herd performance records. The complete dietary measures Dry Matter Intake (DMI, kg/day), CP (%), NDF (%), Feed Quality Score and ME (MJ/kg DM) were all compared to output variables such as Milk Yield (kg/day), Milk Fat (%), Milk Protein (%), Lactose (%), Somatic Cell Count (SCC), Body Condition Score (BCS) and Days in Milk (DIM). All the statistical analysis included Pearson correlation, ordinary least squares (OLS) multiple linear regression modeling and descriptive profiling using python scientific packages.

Results: Mean daily milk yield was 32.23 ± 5.06 kg/day (range: 23.50–42.10 kg/day) with an average DMI of 19.87 ± 1.62 kg/day and a Feed Efficiency ratio of 1.61 ± 0.12 kg milk/kg DMI. Strong positive correlations were observed between Milk Yield and DMI (r = 0.998, p < 0.001), CP (r = 0.998, p < 0.001), ME (r = 0.998, p < 0.001), and Feed Quality Score (r = 0.995, p < 0.001). There was a strong inverse relationship between dietary NDF and Milk Yield (r = -0.996, p < 0.001) while a strong positive relationship between dietary NDF and Milk Fat content (r = 0.998, p < 0.001). In OLS regression (R² = 0.998, F(6, 93) = 10,050, p < 0.001), ME (β = 3.527, p < 0.001), DMI (β = 1.315, p < 0.001), CP (β = 1.233, p = 0.001), and DIM (β = 0.021, p < 0.001) emerged as significant independent predictors of milk volume. FE was primarily driven by dietary ME (β = 0.080, p = 0.005) and CP (β = 0.045, p = 0.006) (R² = 0.994).

Conclusion: Energy density and protein content are the key factors to increased VMP and improved feed efficiency, while sufficient structural fiber (NDF) is essential for maintaining milk fat production. If the TMR formulation is balanced to provide high ME and CP, with adequate effective fiber, it will give maximum conversion efficiency without adversely affecting the milk composition.