Plasma metabolite and hormone responses to rumen inert fat and protein supplies during the dry period in dairy cows

2003 ◽  
Vol 2003 ◽  
pp. 74-74 ◽  
Author(s):  
G. Jaurena ◽  
J. M. Moorby ◽  
N.F.G. Beck

Nutritional regime during the dry period (DP) has been shown to affect lactational performance in dairy cows. These responses could be mediated by a variety of mechanisms (e.g.increased labile body proteins, function of the mammary gland or the liver, or modifying endocrine status), which are likely to exert an overlapping function.This study analysed the effect of protein (P) and/or fat (F) supplementation in the DP on plasma metabolite and hormone concentrations, as a complement to studies on body composition (Jaurena et al. 2001b.) and subsequent milk production (Jaurenaet al., 2001a.) performance. Other results also associated with this work are presented in Jaurenaet al. (2003).

1996 ◽  
Vol 1996 ◽  
pp. 4-4
Author(s):  
R.J. Dewhurst ◽  
D.W.R. Davies ◽  
W.J. Fisher ◽  
K. Aston

Previous studies (Moorbyet al, 1994) have shown that supplementing grass silage with undegradable protein (UDP) during the dry period can lead to increased yields of milk protein and lactose. These studies have often involved restriction of forage intake through limitation of access time and the feeding of straw. This experiment was conducted to assess the effect of UDP supplementation withad libitumaccess to grass silage as well as the effects of restricting forage intakes by including straw in the diets of dry cows.


1997 ◽  
Vol 1997 ◽  
pp. 130-130
Author(s):  
M.G. Goodwill ◽  
N.S. Jessop ◽  
J.D. Oldham

Milk production depends on both the number and activity of secretory cells within the mammary gland. Our earlier work showed the sensitivity of lactational performance to changes in diet during lactation (Goodwill et al, 1996). This study investigated the influence of protein undernutrition and re-alimentation on secretory cell proliferation and death in the mammary gland of rats during early lactation.


2005 ◽  
Vol 2005 ◽  
pp. 19-19
Author(s):  
T. Yan ◽  
R. E. Agnew ◽  
C. S. Mayne

Body condition of lactating dairy cows varies at different stages of lactation. Cows usually mobilise their body reserves to provide energy and protein for milk production in early lactation, and gain weight to deposit energy and protein for pregnancy at a later stage. The objective of the present study was to examine relationships between body condition score (CS) and body concentration of lipid, CP and energy.


1994 ◽  
Vol 61 (3) ◽  
pp. 415-418
Author(s):  
Andrew J. Rook ◽  
Malcolm J. Gibb ◽  
Wendy E. Ivings ◽  
Keith Aston ◽  
John D. Sutton

1994 ◽  
Vol 74 (2) ◽  
pp. 167-201 ◽  
Author(s):  
Jeanne L. Burton ◽  
Brian W. McBride ◽  
Elliot Block ◽  
David R. Glimm ◽  
John J. Kennelly

Unprecedented numbers of technical papers, abstracts, and short communications have been published in the past decade regarding the effects of exogenous bovine growth hormone on milk production, health, and reproductive efficiency of treated dairy cows. In well-managed dairy herds, exogenous growth hormone increases milk production without altering normal variability in milk composition. This has held true regardless of dairy breed tested, geographical location studied, or feeding management system used. Also consistent across studies is the rapidity of the galactopoietic effect of administered bovine growth hormone, which arises from altered partitioning and use of post-absorptive nutrients and increased synthetic capacity of the mammary gland. Growth hormone and its associated peptide, insulin-like growth factor-I, are now known to provide chronic lipolytic, diabetogenic, and gluconeogenic signals to target tissues culminating in increased mammary gland availability of glucose and nonesterified fatty acids. Together with yet ill-defined effects on mammary secretory tissue, this homeorhetic control of metabolism elicited by exogenous growth hormone is so efficient that treated cows are not more susceptible to metabolic disorders than untreated cows. However, some studies have reported an increased frequency of mastitis in groups of treated cows. This has been attributed mainly to increased milk volume in the mammary glands of treated cows and no convincing data are available that show decreased mammary gland immunity as a result of growth hormone treatments. On the contrary, an expanding body of evidence implicates growth hormone as a key neuroendocrine factor that is required for immunological competence. Trends of decreased reproductive efficiency in cows treated with growth hormone have also been reported, but available data imply that this is probably an indirect effect via prolonged negative energy balance in cows treated in early lactation rather than a direct negative effect on estrous cycling via altered reproductive hormone profiles. The objectives of the present review are to bring into focus and summarize pertinent biological discoveries regarding the treatment of dairy cows with recombinant bovine growth hormone, and to explore areas where additional growth hormone research is needed or warranted. Key words: Growth hormone, somatotropin, dairy cows, insulin-like growth factor-I


2005 ◽  
Vol 88 (1) ◽  
pp. 121-127 ◽  
Author(s):  
T.L. Auchtung ◽  
A.G. Rius ◽  
P.E. Kendall ◽  
T.B. McFadden ◽  
G.E. Dahl

2013 ◽  
Vol 198 (3) ◽  
pp. 707-713 ◽  
Author(s):  
Ariëtte T.M. van Knegsel ◽  
Saskia G.A. van der Drift ◽  
Jana Čermáková ◽  
Bas Kemp

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Atsushi Watanabe ◽  
Jiro Hirota ◽  
Shinya Shimizu ◽  
Shigeki Inumaru ◽  
Kazuhiro Kimura

A single intramammary infusion of recombinant bovine interleukin-8 (IL-8) at 50 μg/quarter/head, but not 10 μg/quarter/head, induced clinical mastitis in three of four cows during the dry-off period, resulting in an elevated rectal temperature, redness and swelling of the mammary gland, extensive polymorphonuclear leukocyte (PMNL) infiltration, and milk clot formation from 1 to 28 days post infusion (PI). In the mammary secretions of the mastitic glands, high levels of IL-8 were sustained from 8 hours to 28 days PI, peaking at 1–3 days PI. The levels of leukocyte-derived elastase and inflammatory 22 and 23 kDa lactoferrin derived peptides (LDP) were also increased in the mammary secretions from the mastitic glands. In addition to the experimentally induced mastitis, the mammary secretions from the glands of cattle with spontaneousStaphylococcus aureusdry-period mastitis displayed milk clot formations and significant increases in their levels of PMNL counts, elastase, LDP, and IL-8, compared with those of the mammary secretions from the uninfected glands. These results suggest that after an intramammary infusion of IL-8 has elicited inflammatory responses, it induces the prolonged secretion of elastase, inflammatory LDP, and IL-8, and that long-lasting IL-8-induced inflammatory reactions are involved in the pathogenesis ofS. aureusdry-period mastitis.


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