An investigation into reduced milk production following dietary alteration on an Irish dairy farm

Timothy Geraghty,Finbar J Mulligan,Luke O'Grady

doi:10.1186/2046-0481-63-11-689

Abstract

A nutritional evaluation of an Irish dairy herd indicated gross overfeeding of late lactation cows, over-conditioning of cows at parturition and a high rate of body condition loss in early lactation. Metabolisable-energy based nutritional modelling software was used to guide recommended dietary changes to prevent excessive condition gain in late lactation. Immediately following the implementation of the changes there was an unexpected reduction in performance affecting both milk yield and protein concentration. An investigation into the poor performance revealed underestimation of peak milk yield; over-estimation of maize silage quality; a large difference in the concentrate being fed compared to the concentrate recommended, and failure of the blend of concentrate ingredients to maintain the intended proportions in the in-parlour feeding system. The estimated maximum cumulative effect of these errors was to cause undersupply of energy and protein in the recommended diet of 16% and 3% respectively to cows in early lactation. Use of a net-energy nutritional model would have indicated a requirement for a higher energy supply in this case. This report highlights the challenges in obtaining accurate on-farm data for use in dairy cow nutritional models.

Highlights

Nutritional management of the dairy cow has significant influence on health, production and reproduction around parturition and early lactation (Roche, 2006, Mulligan et al, 2006)
Monitoring nutritional status of the transition cow involves an assessment of nutritional inputs, body condition score changes, milk production performance, the incidence of production diseases, and blood parameters for mineral status and energy balance
Summary and recommendations from the investigation. Results from this investigation revealed several inaccuracies existed in the data collected for use in nutritional modelling software used to direct the initial nutritional changes

Summary

Introduction

Nutritional management of the dairy cow has significant influence on health, production and reproduction around parturition and early lactation (Roche, 2006, Mulligan et al, 2006). The milking cow diets were adjusted with the aim of preventing excessive body condition gain in the remaining late lactation cows by reducing the energy content to match the calculated requirements. As no excess energy supply was found in the dry cow group this diet remained unchanged other than to recommend that dry cows within two weeks of calving be allowed ad-libitum access to a TMR with increased maize silage This was to provide a higher energy diet when dry matter intake was likely to reduce pre-calving, to allow a period for rumen conditioning to a higher energy diet and to account for an increased energy requirement in this group (Table 3). The increased energy and protein requirement resulting from the inaccurately assumed milk yield amounted to 6.4% and 7.1% respectively (Table 4)

In use before nutritional assessment

Methods of calculating nutrient requirements

Findings

Summary and recommendations from the investigation

Discussion