Effect of Genetic Merit and Concentrate Supplementation on Grass Intake and Milk Production with Holstein Friesian Dairy Cows

Abstract

A total of 48 high genetic merit (HM) and 48 medium merit (MM) cows, each given a low (LC), medium (MC), or high (HC) level of concentrate supplementation, were used in a split-plot design experiment, which was run in three consecutive years, to evaluate animal production responses. Individual cow intakes were estimated twice each year while at pasture; measurement period 1 (MP1) was in May/June, and measurement period 2 (MP2) was in early September, corresponding on average to d 110 and 200 of lactation, respectively. In MP1, cows were offered 0 (LC), 3 (MC), and 6 kg (HC), whereas in MP2 the levels were 0 (LC), 0 (MC), and 4 kg (HC) of concentrate daily. Genotype had a significant effect on all milk production parameters in MP1 and MP2. The HM cows had the highest yield of milk, fat, protein, and lactose, whereas the MM cows had the highest milk fat, protein, and lactose concentrations. The HM cows had significantly higher grass dry matter intake (GDMI) estimates. In MP1, the average responses, per kg concentrate dry matter, was +1.10 kg of milk, +0.038 kg of protein, +0.032 kg of fat. The corresponding values in MP2 were +0.94 kg of milk, +0.037 kg of protein, and +0.025 kg of fat. The response to concentrate was linear and independent of preexperimental milk yield. In MP1, the partial regression coefficients relating daily GDMI to an increase in 1 kg of preexperimental milk yield (PMY), preexperimental BW (PBW), and concentrate intake (CI) were 0.123, 0.006, and -0.54, respectively, whereas the corresponding values in MP2 were 0.190,0.007, and-0.444, respectively. This study indicates that with high yielding dairy cows, on gras only GDMI of 17 kg of supporting milk yield of 30-kg/d is achievable. In this scenario, concentrate supplementation will result in lower substitution rates, and higher milk yield response than previously published with lower yielding cows.

Differential response to stocking rates and feeding by two genotypes of Holstein-Friesian cows in a pasture-based automatic milking system

“…The greater gross FCE by USH cows was most likely related to an increased capacity of high-producing animals to partition more nutrients for milk production and synthesis of more milk solids, and to a greater dilution of maintenance requirements (Dijkstra et al, 2013). This differential FCE in favor of USH cows is supported by earlier studies that have documented greater FCE response in high-producing cows when feed availability in pasture-based systems is not a limiting factor to high milk production (Kennedy et al, 2003;Horan et al, 2005). Finally, NZF cows had greater concentration of milk fat and protein, but produced lower total milk solids owing to their lower milk yield.…”

“…low pasture allowance and/or herbage mass) can be achieved more easily (Fariña et al, 2011). On the other hand, the differential response to supplementation can vary widely between cows of different genetic merit, as shown by past comparisons of genotypes and their adaptability to pasture-based systems in conventional parlor milking systems (Kennedy et al, 2003;Horan et al, 2005;Fulkerson et al, 2008). Limited information is available on the differential response to AMS by genotypes that are managed in grazing systems with different stocking rate and supplementation level.…”

Merging and characterising phenotypic data on conventional and rare traits from dairy cattle experimental resources in three countries

“…Data were collated from several studies that had been previously conducted (Buckley et al, 2000;Kennedy et al, 2003;O'Donovan and Delaby, 2005;Horan et al, 2006;Kennedy et al, 2006;McCarthy et al, 2007;McEvoy et al, 2007). In brief, these studies compared either alternative genotypes of Holstein-Friesian cows raised on different production systems or alternative grazing strategies or grass varieties.…”

“…In brief, these studies compared either alternative genotypes of Holstein-Friesian cows raised on different production systems or alternative grazing strategies or grass varieties. Different strains of Holstein-Friesians were evaluated on contrasting grass-based production systems (Buckley et al, 2000;Kennedy et al, 2003;Horan et al, 2006;McCarthy et al, 2007). Animals within strain were randomly assigned, at the start of lactation, to feed systems differing in stocking rate and/or concentrate input.…”

Indices of heart rate variability as potential early markers of metabolic stress and compromised regulatory capacity in dried-off high-yielding dairy cows

“…High performance cattle breeds like German Holstein have been selected for improved milk production and thereby also for high ad libitum feed intake and metabolic rates (Kennedy et al, 2003). On the other hand, dairy cows experience distinct metabolic stress during periods of high metabolic load and inadequate energy/fuel availability leading to a negative energy balance (NEB), for example, as a result of infectious or metabolic/digestive disorders, during heat stress, and in particular during the transition period around parturition (Gross et al, 2011).…”