Performance, Physiological Status, and Heat Tolerance of Holstein Friesian Dairy Cows at Different Lactation Phases

Abstract

The lactation period in Holstein Friesian dairy cows has a significant impact on their production performance. Therefore, it is important to observe and determine the dairy cows’ physiological status, performance, and heat tolerance at different lactation phases. This study utilized a completely randomized design with three experimental and five replicates, involving 15 Holstein Friesian Dairy Cows. The cows were divided into three experimental based on their lactation phase i.e., early lactation (1–3 months) post-partum; middle lactation (4–6 months) post-partum; and late lactation phase (7–10 months), respectively. The study revealed that the lactation phase had a significant effect on the body condition score (P=0.04) and respiratory frequency (P=0.02). However, it had no significant effect (P>0.05) on either dry matter intake of forage, concentrate, total consumption, milk yield, feed conversion efficiency, heart rate, body temperature, heat tolerance coefficient, or Benezra coefficients. In early lactation, dairy cows are susceptible to negative energy balance, which can reduce performance and affect physiological values. Proper feed intake can help address the negative energy balance (NEB), many cows get NEB during this phase. Performance and physiological values at different phases vary, requiring adjustments to nutritional intake based on the lactation phase.