Animal Science Abstract
The effect of strain of Holstein-Friesian dairy cow and pasture-based system on grass intake and milk production
B. Horan1,2, P. Faverdin3, L. Delaby3, M. Rath2 and P. Dillon1,A
ACorresponding author: E-mail: pdillon@moorepark.teagasc.ie
1Dairy Production Department, Teagasc, Dairy Production Research Centre, Moorepark, Fermoy, Co. Cork, Ireland2Department of Animal Science, Faculty of Agriculture, University College Dublin, Belfield, Dublin 4, Ireland
3INRA, UMR Production du Lait, 35590 St Gilles, France
Abstract
The objective of this study was to investigate the effects of strain of Holstein-Friesian cow, pasture-based feeding system (FS) and their interaction on milk production, dry matter (DM) intake and energy balance over 3 years consecutively. The three strains were: high milk production North American (HP), high fertility and survival (durability) North American (HD) and New Zealand (NZ). The FS were: a high grass allowance (HG FS), a high concentrate (HC FS) and a high stocking rate (HS FS). A separate farmlet existed for each FS and a total of 99, 117 and 117 animals were used in year 1, year 2 and year 3, respectively, divided equally between strains and FS. Individual animal intakes were estimated three times each year at pasture; in May (P1), in July (P2) and October (P3), corresponding on average to day 102, 177 and 240 of lactation, respectively. The HP cows achieved the highest milk yield, the NZ the lowest, while the HD was intermediate; the HP achieved the highest solid corrected milk yield with no difference between the NZ and HD strains. The grass DM intake of the HP strain was highest (P<0.001) in all feeding systems. There was a significant strain × FS interaction for yield of milk, fat and protein, grass DM and total DM intake. The milk production response to the HC FS in P1 and P2 was significantly greater for both the HP and HD strains than for the NZ strain, while in P3 the response was highest for the HP, lowest for the NZ and intermediate for the HD. The reduction in pasture DM intake per kg of concentrate was greatest for the NZ strain, lowest for the HP and intermediate for the HD strain. The NZ strain also had the highest grass DM intake per kg live weight. The existence of strain × FS interactions for production and DM intake indicate that greater knowledge of both genotype and feeding environment is required to predict animal performance.
Keywords: dairy cows, energy balance, food intake, Holstein-Friesian, milk production.
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