Research articleEffect of grass dry matter intake and fat supplementation on progesterone metabolism in lactating dairy cows
Introduction
Genetic selection programs during the past two decades have resulted in a modern dairy cow capable of producing large volumes of milk on high intake diets. The improvement has come at the expense of fertility and longevity, however, and the reproductive performance of dairy cows has been declining over the past 50 yr [1]. Embryo loss is the greatest factor contributing to reproductive inefficiency in dairy cows, with combined embryonic and fetal loss rates in high producing dairy cows averaging approximately 60% [2].
There is substantial evidence of a link between embryo survival and systemic concentrations of progesterone (P4) in both the cycle before ovulation and during the early luteal phase of the cycle after insemination [2]. Positive linear and quadratic relationships have been identified between milk P4 concentrations on Days 4, 5, 6, and 7 after insemination, and also between the rate of change in P4 concentrations between Days 4 and 7 inclusive, and embryo survival [3], [4]. Low circulating P4 concentrations around the time the developing blastocyst arrives in the uterine horn may affect the volume and/or composition of uterine secretions essential for embryo survival, rate of conceptus development, and the ability of the embryo to produce bovine interferon-tau (bIFN-τ) [5].
Progesterone in blood is almost completely metabolized in a single pass through the liver [6]. Liver blood flow (LBF) and metabolic clearance rate (MCR) of P4 are elevated by increasing dry matter intake (DMI) in pigs [7], sheep [6], and dairy cattle [8], [9]. Increased MCR of P4 reduces peripheral plasma P4 concentrations due to the inability of the corpus luteum to sufficiently increase its rate of P4 secretion to maintain homeostasis [6].
Fat supplementation has been shown to increase plasma P4 concentrations [10], [11], [12]. This has been hypothesized to be due to increased plasma cholesterol concentrations, the precursor essential for steroid synthesis [13]. This hypothesis has been questioned by Hawkins et al. [12], however, who observed that fat supplementation resulted in greater P4 half-life (t½) in circulation compared with control cows receiving no fat supplement. This indicates that reduced MCR is a major contributing factor to the increased plasma P4 concentrations in cows fed a high lipid diet.
Our objective was to determine the effects of herbage allowance and dietary fat supplementation on the t½ and clearance rate of plasma P4 in lactating dairy cows. We hypothesized that substituting a proportion of grass dry matter intake (GDMI) with supplementary fat would reduce the MCR of P4.
Section snippets
Animals and treatments
All experimental procedures involving animals were licensed by the Department of Health and Children, Ireland, in accordance with the Cruelty to Animals Act (Ireland 1876) and the European Community Directive 86/609/EC. Forty mid- to late-lactation (178 days in milk (DIM) ± 12 days SD) Holstein-Friesian cows were blocked on the basis of parity, calving date, body weight (BW) and body condition score (BCS), and randomly assigned to 1 of 2 pasture allowances (ad libitum allowance [AL], 9.5 kg dry
Milk production and composition, body weight, and body condition score
Milk production and composition, body weight, and BCS data are presented in Table 2. Milk yield was 1.48 kg per day less for cows receiving the R grazing allowance compared with cows receiving the AL grazing allowance (P = 0.002). Cows receiving the R grazing allowance produced 0.06 kg per day less milk fat (P = 0.001), 0.05 kg per day less milk protein (P = 0.006), and 0.07 kg per day less milk lactose (P = 0.02) compared with cows receiving the AL grazing allowance. Collectively, this
Discussion
The objective of the current study was to determine the effects of different levels of GDMI and fat supplementation on the t½ and MCR of P4 in lactating dairy cows. The dietary treatments used in the current study had little effect on either the t½ or MCR of plasma P4, although there was a tendency for an increased t½ of plasma P4 in fat-supplemented cows on the R grazing treatment.
A number of studies have established a positive association between DMI and the MCR of P4 [9], [21]. The lack of
Acknowledgments
The authors thank Mr. J.P Murphy, Mr. F. Coughlan, and the Moorepark farm staff for the management and care of the animals. The technical assistance of Mr. J. Kenneally, Mr. M. Feeney, Ms. C. Flemming, and Ms. N. Galvin (Teagasc Moorepark), and Ms. P. Furney and Ms. N. Hynes (UCD), is also much appreciated. Funding from the National Development Plan and the Dairy Levy Research Trust are gratefully acknowledged.
References (28)
Reproductive loss in high-producing dairy cattle: where will it end?
J Dairy Sci
(2001)- et al.
Effect of progesterone on embryo survival
Animals
(2008) - et al.
Associations between milk progesterone concentration on different days and with embryo survival during the early luteal phase in dairy cows
Theriogenology
(2006) - et al.
Post-insemination milk progesterone concentration and embryo survival in dairy cows
Theriogenology
(2005) - et al.
High feed intake increases liver blood flow and metabolism of progesterone and estradiol-17beta in dairy cattle
J Dairy Sci
(2002) - et al.
Influence of supplemental fats on reproductive tissues and performance of lactating cows
J Dairy Sci
(1998) - et al.
Prediction of the energy value of cow's milk
J Dairy Sci
(1965) - et al.
A body condition scoring chart for holstein dairy cows
J Dairy Sci
(1989) - et al.
Effect of pregrazing herbage mass on methane production, dry matter intake, and milk production of grazing dairy cows during the mid-season period
J Dairy Sci
(2010) - et al.
Changes in reproductive physiology of lactating dairy cows due to elevated steroid metabolism
Theriogenology
(2006)
Progesterone clearance rate in lactating dairy cows with two levels of dry matter and metabolisable energy intakes
Anim Reprod Sci
Conjugation, distribution, and biological half-life (t ½) of radioactive progesterone in plasma and red cells of bovine blood
J Dairy Sci
In vitro and in vivo analysis of fatty acid effects on metabolism of 17beta-estradiol and progesterone in dairy cows
J Dairy Sci
Effects of level of feeding and progesterone dose on plasma and faecal progesterone in ovariectomised cows
Anim Reprod Sci
Cited by (8)
Metabolic & reproductive characteristics of replacement beef heifers subjected to an early-weaning regimen involving high-concentrate feeding
2017, AnimalCitation Excerpt :A progesterone clearance analysis was conducted 2 days following the epinephrine challenge. Blood samples (10 ml) were collected at −45, −30, −15, 0, 7.5, 15, 30, 45, 60, 90, 120 and 180 min relative to progesterone administration as described by Hutchinson et al. (2012). A progesterone bolus (350 ng/kg BW; Watson Pharma Inc., Parsippany, NJ, USA) was administered in the same manner described for previous challenges.
Postinsemination diet change on reproductive performance in beef heifers
2016, Professional Animal ScientistCitation Excerpt :Furthermore, there tended to be an interaction between DMI and fat supplementation on progesterone half-life. Half-life was 7.1 min shorter in fat supplemented cows that had ad libitum access to forage (9.5 kg of DM per d) compared with cows that were fat supplemented and had DMI restricted (7 kg of DM per d), and 4.3 min shorter in ad libitum DMI fat supplemented cows compared with ad libitum DMI nonfat supplemented cows (Hutchinson et al., 2012a). In the present study, heifers had ad libitum access to forage after AI, and the drylot treatment was fed at 2.5% of BW.
Genetic merit for fertility traits in Holstein cows: V. Factors affecting circulating progesterone concentrations
2014, Journal of Dairy ScienceCitation Excerpt :Increased liver blood flow due to greater DMI (Sangsritavong et al., 2002; Reynolds et al., 2003) and the associated increase in liver steroid clearance has been implicated as a potential disruptor of reproductive events in high-producing dairy cows. Sangsritavong et al. (2002), Lemley et al. (2010a), and Hutchinson et al. (2012) have reported that it is possible to alter P4 clearance through dietary manipulation. The major genes responsible for P4 catabolism in the liver belong to the cytochrome P450 family (Murray, 1991, 1992).
Comparison of fertility, regular returns-to-estrus, and calving interval between Ovsynch and CO-synch + CIDR protocols in dairy cows
2014, TheriogenologyCitation Excerpt :The increase in dry matter intake and milk production per cow in the last decades has been concurrent with a dramatic decline in fertility in dairy commercial herds [1,2]. A negative relation was observed between circulating progesterone (P4) concentrations and dry matter intake in lactating dairy cows [3]. In intensively managed dairy herds with high-producing dairy cows, a negative association between high milk production and expression of behavioral estrus was also observed [1,4,5], showing the importance of timed artificial insemination (TAI) as part of synchronization strategies, with or without estrus detection.
Reproductive response, metabolic state and body changes in ewes supplemented with two energy levels
2021, Revista MVZ Cordoba