Effects of level of concentrate feeding during the second gestation of Holstein-Friesian dairy cows. 2. Nitrogen balance and plasma metabolites

JM Moorby, RJ Dewhurst, RT Evans, WJ Fisher

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Abstract

We offered 43 Holstein-Freisian dairy heifers that calved for the first time at either 2 or 3 yr of age ad libitum access to ryegrass silage and a standard concentrate allowance of either 2 or 7 kg/d from the middle to the end of their first lactation. All animals were given the same relatively poor quality dry period diet of a mixture of ryegrass silage and barley straw (63:37 dry matter basis) from 6 wk before their predicted second-calving date. Following their second calving, all animals received access to the same ration of ad libitum grass silage and concentrates at a rate of 8 kg/d to 120 d of lactation and 5 kg/d thereafter until the end of the experimental recording at about 150 d of lactation. Nitrogen balance was significantly higher at the end of the first lactation for animals that were given the higher concentrate allowance and tended to be higher for older animals. There was no effect of age or residual effect of concentrate allowance on N balance during the dry period or during the second lactation. Labile body protein reserves, as estimated by the depth of the muscle Longissimus dorsi (which was significantly correlated with body condition score), were similar for all animals during the dry period, but younger animals previously offered the lower concentrate allowance did not lose L. dorsi depth early in the second lactation as did other animals. Arterial plasma concentrations of amino acids Phe, Trp, and Leu were significantly higher in younger animals at wk 8 of the second lactation, and Gly was significantly lower, although mammary blood flow, arteriovenous differences, and rates of uptake of the AA measured were unaffected by treatment. It is concluded that differences in second-lactation milk yield were not mediated through the availability of labile body protein or the supply of nutrients to the mammary gland.
Original languageEnglish
Pages (from-to)178-189
JournalJournal of Dairy Science
Volume85
Issue number1
Publication statusPrint publication - Jan 2002

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nitrogen balance
Holstein
dairy cows
lactation
concentrates
pregnancy
metabolites
dry period (lactation)
grass silage
body protein
young animals
animals
longissimus muscle
calving
barley straw
dairy heifers
residual effects
mammary glands
blood flow
breasts

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title = "Effects of level of concentrate feeding during the second gestation of Holstein-Friesian dairy cows. 2. Nitrogen balance and plasma metabolites",
abstract = "We offered 43 Holstein-Freisian dairy heifers that calved for the first time at either 2 or 3 yr of age ad libitum access to ryegrass silage and a standard concentrate allowance of either 2 or 7 kg/d from the middle to the end of their first lactation. All animals were given the same relatively poor quality dry period diet of a mixture of ryegrass silage and barley straw (63:37 dry matter basis) from 6 wk before their predicted second-calving date. Following their second calving, all animals received access to the same ration of ad libitum grass silage and concentrates at a rate of 8 kg/d to 120 d of lactation and 5 kg/d thereafter until the end of the experimental recording at about 150 d of lactation. Nitrogen balance was significantly higher at the end of the first lactation for animals that were given the higher concentrate allowance and tended to be higher for older animals. There was no effect of age or residual effect of concentrate allowance on N balance during the dry period or during the second lactation. Labile body protein reserves, as estimated by the depth of the muscle Longissimus dorsi (which was significantly correlated with body condition score), were similar for all animals during the dry period, but younger animals previously offered the lower concentrate allowance did not lose L. dorsi depth early in the second lactation as did other animals. Arterial plasma concentrations of amino acids Phe, Trp, and Leu were significantly higher in younger animals at wk 8 of the second lactation, and Gly was significantly lower, although mammary blood flow, arteriovenous differences, and rates of uptake of the AA measured were unaffected by treatment. It is concluded that differences in second-lactation milk yield were not mediated through the availability of labile body protein or the supply of nutrients to the mammary gland.",
author = "JM Moorby and RJ Dewhurst and RT Evans and WJ Fisher",
year = "2002",
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language = "English",
volume = "85",
pages = "178--189",
journal = "Journal of Dairy Science",
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Effects of level of concentrate feeding during the second gestation of Holstein-Friesian dairy cows. 2. Nitrogen balance and plasma metabolites. / Moorby, JM; Dewhurst, RJ; Evans, RT; Fisher, WJ.

In: Journal of Dairy Science, Vol. 85, No. 1, 01.2002, p. 178-189.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Effects of level of concentrate feeding during the second gestation of Holstein-Friesian dairy cows. 2. Nitrogen balance and plasma metabolites

AU - Moorby, JM

AU - Dewhurst, RJ

AU - Evans, RT

AU - Fisher, WJ

PY - 2002/1

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N2 - We offered 43 Holstein-Freisian dairy heifers that calved for the first time at either 2 or 3 yr of age ad libitum access to ryegrass silage and a standard concentrate allowance of either 2 or 7 kg/d from the middle to the end of their first lactation. All animals were given the same relatively poor quality dry period diet of a mixture of ryegrass silage and barley straw (63:37 dry matter basis) from 6 wk before their predicted second-calving date. Following their second calving, all animals received access to the same ration of ad libitum grass silage and concentrates at a rate of 8 kg/d to 120 d of lactation and 5 kg/d thereafter until the end of the experimental recording at about 150 d of lactation. Nitrogen balance was significantly higher at the end of the first lactation for animals that were given the higher concentrate allowance and tended to be higher for older animals. There was no effect of age or residual effect of concentrate allowance on N balance during the dry period or during the second lactation. Labile body protein reserves, as estimated by the depth of the muscle Longissimus dorsi (which was significantly correlated with body condition score), were similar for all animals during the dry period, but younger animals previously offered the lower concentrate allowance did not lose L. dorsi depth early in the second lactation as did other animals. Arterial plasma concentrations of amino acids Phe, Trp, and Leu were significantly higher in younger animals at wk 8 of the second lactation, and Gly was significantly lower, although mammary blood flow, arteriovenous differences, and rates of uptake of the AA measured were unaffected by treatment. It is concluded that differences in second-lactation milk yield were not mediated through the availability of labile body protein or the supply of nutrients to the mammary gland.

AB - We offered 43 Holstein-Freisian dairy heifers that calved for the first time at either 2 or 3 yr of age ad libitum access to ryegrass silage and a standard concentrate allowance of either 2 or 7 kg/d from the middle to the end of their first lactation. All animals were given the same relatively poor quality dry period diet of a mixture of ryegrass silage and barley straw (63:37 dry matter basis) from 6 wk before their predicted second-calving date. Following their second calving, all animals received access to the same ration of ad libitum grass silage and concentrates at a rate of 8 kg/d to 120 d of lactation and 5 kg/d thereafter until the end of the experimental recording at about 150 d of lactation. Nitrogen balance was significantly higher at the end of the first lactation for animals that were given the higher concentrate allowance and tended to be higher for older animals. There was no effect of age or residual effect of concentrate allowance on N balance during the dry period or during the second lactation. Labile body protein reserves, as estimated by the depth of the muscle Longissimus dorsi (which was significantly correlated with body condition score), were similar for all animals during the dry period, but younger animals previously offered the lower concentrate allowance did not lose L. dorsi depth early in the second lactation as did other animals. Arterial plasma concentrations of amino acids Phe, Trp, and Leu were significantly higher in younger animals at wk 8 of the second lactation, and Gly was significantly lower, although mammary blood flow, arteriovenous differences, and rates of uptake of the AA measured were unaffected by treatment. It is concluded that differences in second-lactation milk yield were not mediated through the availability of labile body protein or the supply of nutrients to the mammary gland.

UR - https://doi.org/10.3168/jds.S0022-0302(02)74066-6

M3 - Article

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JF - Journal of Dairy Science

SN - 0022-0302

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