Effect Of Negative Energy Balance Research Articles

Effect of Bypass Fat and Bypass Protein Supplementation During Transition Period on Reproductive Performance of Assam Hill Goat

The present study was undertaken to evaluate the response of Assam Hill Goat (AHG) in terms of their productive and reproductive performances upon bypass fat and bypass protein supplementation during the transition period. Twenty-four AHG in transition period (21day prepartum to 21day post-partum) were divided into two equal groups (n=12) viz. T-0 and T-1; where Group T-1 was supplemented with 10 g of bypass fat and 5 g of bypass protein along with their normal diet for a period of 42 days. Group T-0 acted as control and was provided with a normal diet without any supplementation. Blood samples were collected on day -21, -14, -7, 0 (day of kidding), +7, +14 and +21 of the transition period for haemato-biochemical studies. Birth weight, milk yield and time taken for expulsion of foetus and foetal membrane and incidences of peri-partum diseases were recorded. The results indicated that, the supplementation had no significant effect on haematological parameters (TLC, Neutrophil count and Hb), serum Ca, P, glucose, globulin and GGT activity. Serum non-esterified fatty acids (NEFA) levels were significantly (p<0.05) lower in supplemented groups on the day of kidding (0.75±0.09 mmol/L) and day 21 of postpartum (0.38±0.04 mmol/L). Significantly (p<0.05) higher mean values of total protein on day -14, -7, 0, 7, 14 and 21 (6.96±0.21, 6.99±0.25, 7.02±0.26, 7.24±0.28, 7.03±0.12 and 6.95±0.15 g/dL) and serum albumin values on day -14, 7 and 21 (4.46±0.23, 4.69±0.23 and 4.44±0.27 g/dL) were recorded in T-1 group. Significantly (p<0.05) lower mean values of BUN were recorded in T-1 group on day 0, 7 and 21 (30.25±1.74, 35.62±1.58 and 42.08±1.45 mg/dL). The supplemented (T–1) group recorded significantly higher milk yield (303.5±21.16, 306.25±19.67 and 310.75±23.93 ml) on day 14, 21 and 28 after kidding and there was a significant (p<0.05) reduction in time taken for the expulsion of foetus (89.75±11.84 mins) and foetal membranes (90.50±5.86 mins). The supplementation of bypass fat (10g/day) and bypass protein (5 g/day) during the transition period reduce the effect of negative energy balance and facilitate quicker recovery from negative energy balance along with improvement in milk yield and reduce time taken for expulsion of foetus and foetal membrane.

Genetic correlations between milk fatty acids grouped according to origin until 95 days in milk and fertility of Holstein cows in Japan.

Mitigating the effect of negative energy balance in early lactation is important for improving the fertility of dairy cows, and milk fatty acid (FA) composition may reflect energy status. We used insemination records and monthly test-day records to examine the genetic relationships between FAs grouped according to origin (FAOs) at early lactation and fertility traits in the first lactation of Japanese Holstein cows. The FAO traits we assessed were de novo FAs (C4:0 to C14:0) on a milk basis (DnM) and on a total FA basis (DnF) and preformed FAs (C15:0 and ≥ C17:0) on a total FA basis during 95 days in milk (DIM). The fertility traits evaluated were conception rate at first insemination (CR) and days open (DO). We applied a two-trait (each FAO and fertility trait) linear model to estimate the genetic correlations between them. The genetic correlations of DnM and DnF within 35 DIM with CR were 0.44 and 0.31, respectively, and those with DO were -0.27 and -0.26, respectively. These results suggest that genetic improvement in de novo FAs within 35 DIM could help to increase fertility in the first lactation.

Effect of negative energy balance on plasma metabolites, minerals, hormones, cytokines and ovarian follicular growth rate in Holstein dairy cows

IntroductionThe aim of this study was to evaluate the effect of negative energy balance (NEB) on the final growth of the dominant ovarian follicle in Holstein cows.Material and MethodsCows at 14 to 21 d postpartum from an intensive dairy farm were randomly selected and allocated into a positive energy balance group (PEB, with β-hydroxybutyric acid (BHBA) level < 1.2 mmol/L, n = 15) and an NEB group (BHBA > 1.2 mmol/L, n = 15). Plasma samples were collected at 21, 50 and 55 d postpartum to assess the concentrations of energy metabolites, minerals, hormones and cytokines. Ovaries were examined by transrectal ultrasound on days 50 and 55 (120 hours later) to evaluate the diameter of the largest follicle.ResultsCompared with PEB cows, there were a more severe body condition loss and a lower milk yield in NEB cows (P < 0.05) and these had greater concentrations of plasma BHBA, non-esterified fatty acids, triglycerides, urea nitrogen, growth hormone, interleukin 6, and fibroblast growth factor 21 and lesser concentrations of plasma glucose, total cholesterol, insulin, insulin-like growth factor 1, insulin-like growth factor binding protein 3, leptin, brain-derived neurotrophic factor and angiopoietin-like protein 8 on d 21 (P < 0.05), while plasma minerals were not affected by energy status (P > 0.05). These changes persisted until the end of the study period (50–55 days postpartum) resulting in a lower follicular growth rate for cows in the NEB than the PEB group.ConclusionThese observations indicate that follicular growth rate is associated with measurable changes in energy metabolite, hormone and cytokine concentrations caused by early postpartum NEB.

196 Steroid concentrations in bovine follicular fluid are affected by metabolic stress

The negative energy balance (NEB) in dairy cows, early postpartum, is related to reduced fertility. A metabolic characteristic of NEB is elevated levels of free fatty acids (NEFA) in blood and follicular fluid with an effect on the cumulus-oocyte complex (COC; Leroy et al. 2005 Reproduction 130, 485-495, https://doi.org/10.1530/rep.1.00735; Aardema et al. 2011 Biol. Reprod. 85, 62-69, https://doi.org/10.1095/biolreprod.110.088815; Aardema et al. 2013 Biol. Reprod. 88, 164, https://doi.org/10.1095/biolreprod.112.106062). In this study, we investigated the effect of elevated NEFA levels on granulosa cells and consequently steroid production during NEB. Both 17β-oestradiol (E2) and progesterone (P4) levels in follicular fluid and oocyte competence were measured during NEB, as oocyte competence and steroid production are related (Aardema et al. 2013 Theriogenology 80, 576-583, https://doi.org/10.1016/j.theriogenology.2013.05.025). Heifers were directed towards a control (CTR; n=6) or NEB group (NEB; n=6; fasting heifer model; Jorritsma et al. 2003 Theriogenology). Cycle synchronization and superstimulation were performed as previously reported; invivo matured oocytes were, by ovariectomy at 22h after the induced LH peak, individually collected from follicles (≥8 to ≤20mm) and invitro fertilized and cultured until Day 8. Levels of nonesterified fatty acids (NEFAs) in follicular fluid were, in CTR, 80μM palmitic (C16:0), 70μM stearic (C18:0), and 100μM oleic acid (C18:1) and, in NEB, 150μM C16:0, 100μM C18:0, and 200μM C18:1 (Aardema et al. 2013 Biol. Reprod. Vol, page range). Follicular fluid of individual follicles was frozen and stored at −20°C until E2 and P4 radioimmunoassay analysis. At Day 5 and 8 of culture, embryos were scored for developmental competence, according to Aardema et al. (2013 Biol. Reprod. Vol, page range). Oocytes developing to a blastocyst all originated from follicles with, formerly in control animals defined, optimal follicular fluid levels of E2 ≤0.25 μM and P4 ≥0.26 μM (Aardema et al. 2013 Theriogenology 80, 576-583, https://doi.org/10.1016/j.theriogenology.2013.05.025). Overall E2 levels in follicular fluid in NEB appeared to be lower than those in CTR. There was a reduced positive value of 0.33 (vs. 0.49 in CTR) for predicting the competence of oocytes to develop into a blastocyst, and reduced specificity of 0.26 (vs. 0.75 in CTR) for oocytes originating from follicles with optimal steroid levels in NEB. The sensitivity and negative predictive value were 1.0 in both NEB and CTR. Levels of P4 in follicular fluid were unaffected by NEB. The lower level of E2 indicates an effect of NEB on steroid synthesis in granulosa cells. Recently, it was demonstrated that invitro exposure to monounsaturated C18:1, in contrast to saturated C16:0 or C18:0, resulted in reduced E2 production and expression of CYP19A1 in granulosa cells (Sharma 2018 Endocrine Connections 8, 493-505, https://doi.org/10.1530/EC-19-0011). These data suggest that elevated levels of NEFAs, C18:1 in particular, affect the function of granulosa cells and the follicular steroid environment of the COC, in contrast to the effect of C18:1 on the COC, which appears to protect the oocyte against lipotoxic events by saturated NEFAs by massive lipid accumulation in cumulus cells (Aardema et al. 2011 Biol. Reprod. 85, 62-69, https://doi.org/10.1095/biolreprod.110.088815; Aardema et al. 2013 Biol. Reprod. 88, 164, https://doi.org/10.1095/biolreprod.112.106062). Elevated levels of C18:1 may also result in increased lipid storage in granulosa cells and could affect the steroid synthesis of cholesterol that is also stored in lipid droplets. How elevated NEFA levels during the NEB affect granulosa cells is under investigation.

Combating Negative Effect of Negative Energy Balance in Dairy Cows: Comprehensive Review

Approaches in Poultry, Dairy & Veterinary Sciences Combating Negative Effect of Negative Energy Balance in Dairy Cows: Comprehensive Review Amanuel Bekuma1* and Ulfina Galmessa2 1Department of Animal Science, Mettu University, Bedele, Ethiopia 2Ethiopian Institutes of Agricultural Research (EIAR), Holeta, Ethiopia *Corresponding author:Amanuel Bekuma, Department of Agriculture and Forestry, Ethiopia Submission: May 09, 2019;Published: June 25, 2019 DOI: 10.31031/APDV.2019.06.000633 ISSN: 2576-9162 Volume6 Issue2

Innate defense capability of challenged primary bovine mammary epithelial cells after an induced negative energy balance in vivo.

Negative energy balance (NEB), if followed by metabolic imbalance, is a common problem in high-yielding dairy cows frequently associated with inflammation of the mammary gland. After entering the teat canal, mammary epithelium is the first line of defense against a pathogen invasion. To investigate the effect of NEB on the innate host defense of the mammary epithelium, primary bovine mammary epithelial cell (pbMEC) cultures were generated by cell extraction of milk derived from energy restricted and control feeding cows. pbMEC were obtained from 8 high-yielding dairy cows affected by induced NEB in mid-lactation due to a reduction to 51 ± 2% of total energy requirement (restriction group) and from 7 control cows (control group). They were exposed to heat-inactivated Escherichia coli and Staphylococcus aureus for 24 and 72 h to investigate the influence of NEB on gene expression profiles of cytokines, chemokines, genes associated with apoptosis and antimicrobial peptides plus their receptors (AMPR) of the innate immune response. The immune challenge of pbMEC demonstrated an effect of immune capacity and NEB in 15 differential expressed genes. NEB induced a substantial up-regulation in restriction compared to control cells by trend in E. coli and a down-regulation in S. aureus exposed cells. Our investigations showed that the dietary-induced NEB in vivo influenced the immune response of pbMEC in vitro and altered the expression of immunological relevant genes due to a difference in energy supply. These results demonstrate that pbMEC are a suitable model for mastitis research, in which even effects of feeding regimes can be displayed.

0137 The endometrial microbiome in transition cows fed an energy-restricted diet

The objective of this study was to evaluate the effect of negative energy balance (NEB) on the endometrial microbiome of transition cows. Ten Holstein cows blocked by parity, BW, and BCS were randomly assigned to two groups: control (CTL) and NEB (80% of the net energy required). Endometrial cytobrush samples were collected at 14 and 35 d postpartum (DPP) and DNA was extracted using a QIAamp DNA Micro Kit. Based on next generation sequencing of 16S rRNA genes, 403 operational taxonomic units (OTUs) were detected. All continuous variables were analyzed by ANOVA. A comparison of the alpha diversity, based on the number of OTUs present, revealed no significant differences in uterine microbiome diversity between 14 and 35 DPP in the CTL group, but significantly (P < 0.05) lower diversity 14 and 35 DPP within the NEB group. The CTL group microbiome on 14 DPP showed significantly (P < 0.05) higher diversity compared with the NEB group. At genus level, the majority of OTUs detected were shared between 14 and 35 DPP (CTL, 47/68 [69%]; NEB, 40/65 [61.5%]) within both groups. However, in the CTL group, there were 16 OTUs detected at 14 DPP that were not present at 35 DPP, while 5 OTUs found at 35 DPP were not detected at 14 DPP; in the NEB group, 4 OTUs at 14 DPP were not detected at 35 DPP, whereas 21 OTUs detected at 35 DPP were not present on 14 DPP. At phylum level, on 14 DPP, Proteobacteria (39.2 vs. 0.46%) and Firmicutes (44.3 vs. 33.7%) were higher in CTL compared with the NEB uterine microbiome; Bacteroidetes (29.9 vs. 8.9%), Fusobacteria (14.3 vs. 3.4%), and unassigned (20.1 vs. 1.4%) phyla predominated in NEB compared with CTL. On 35 DPP, the CTL microbiome was predominated by Cyanobacteria and Proteobacteria sequences, while the NEB microbiome was predominated by Firmicutes and Bacteroidetes. Differences in Proteobacteria and Bacteroidetes levels at 14 and 35 DPP, respectively, were statistically significant (P < 0.05). Relative abundances of Actinobacteria, Cyanobacteria, and Proteobacteria were significantly higher at 35 DPP compared with 14 in NEB cows. No significant differences were detected in CTL. Our preliminary data although inconclusive due to small sample size and individual animal microbiome variations suggest that there might be some microbiome composition differences between the CTL and NEB at 14 and 35 dpp.

The relationship between energy balance after calving and reproductive functions in Holstein dairy cows treated by the OVSYNCH system

The objective of this research was to evaluate the relationship between the course and the depth of negative energy balance (NEB) rated by changes of the body condition after calving and subsequent recovery of reproductive abilities of Holstein dairy cows treated by OVSYNCH. The body condition was evaluated by the BCS system one week before calving and subsequently at 30-day intervals for the period of 6 months of lactation. Recovery of ovarian functions was evaluated by the results of ultrasound examination of all the dairy cows’ ovaries in two controls after calving. The first one was performed on an average of 67 days after calving, and the second at a 60-day interval. The occurrence of individual findings - the presence of corpus luteum, ovarian cysts or ovaries without findings was evaluated as an effect of NEB on the recovery of the ovarian cycle of dairy cows and their subsequent possibility of conception. The suitable cows were treated by the OVSYNCH system after the 1st and 2nd ultrasound examination. Therefore, the insemination interval was calculated and in the case of dairy cows, pregnancy detection, also the number of services per conception and the length of open days. Twice performed hormonal treatment of 73.6% of the animals delayed the period by 50.2 days. In all, 202 dairy cows calved in the period from 29th July 2011 to 7th February 2012 were included in this observation. Significant effects of the body condition change on the ovarian activity as documented by sonographic examination and reproductive indicators appeared primarily in the second month of lactation. The best reproductive indicators were found in cows with the lowest body condition change, thus with a small decline or even increase of body condition score (−0.0 to +0.75 points, P &lt; 0.05). On the contrary, the worst level of indicators of recovery of the reproduction functions were documented in the dairy cows with the most marked decline of BCS (P &lt; 0.05).

The Influence of Intensive Physical Training on Salivary Adipokine Levels in Elite Rhythmic Gymnasts

Exercise challenges homeostasis and establishes a new dynamic equilibrium. Elite Rhythmic Gymnasts (RG's) begin exercise at an early age, undergo physical and psychological stress, and adopt negative energy balance to retain a lean physique. The aim of the present study was to evaluate the effect of negative energy balance, acute and chronic exercise on salivary adiponectin, resistin and visfatin levels and their interaction with salivary cortisol, and insulin levels in elite RG's. This study is unique in character, as all variables were assessed on the field of competition. The study included 51 elite RG's participating in "Kalamata 2010 World Cup" in Kalamata, Greece on April 2010. Twenty-seven healthy age-matched girls were used as controls. Anthropometric values were assessed; baseline and post exercise salivary cortisol, insulin, adiponectin, resistin, and visfatin levels were measured. Comparisons regarding hormonal features between RG's and controls were adjusted for BMI and body fat percentage. Salivary adiponectin levels were higher (p<0.05) and visfatin lower (p=0.094) in RG's compared with controls, while no significant changes were observed regarding salivary cortisol, insulin, and resistin levels. In elite RG's acute intensive anaerobic exercise led to increased salivary insulin levels (p<0.001), reduced salivary adiponectin (p<0.001) and visfatin levels (p<0.05), and no changes in salivary resistin levels. Moreover, diurnal variation of salivary cortisol was lost. In elite RG's salivary adiponectin is upregulated and salivary visfatin is downregulated after chronic intensive exercise and negative energy balance, while both salivary adiponectin and visfatin levels are suppressed after short term intensive anaerobic exercise.

Functional Adaptations of the Transcriptome to Mastitis-Causing Pathogens: The Mammary Gland and Beyond

Application of microarrays to the study of intramammary infections in recent years has provided a wealth of fundamental information on the transcriptomics adaptation of tissue/cells to the disease. Due to its heavy toll on productivity and health of the animal, in vivo and in vitro transcriptomics works involving different mastitis-causing pathogens have been conducted on the mammary gland, primarily on livestock species such as cow and sheep, with few studies in non-ruminants. However, the response to an infectious challenge originating in the mammary gland elicits systemic responses in the animal and encompasses tissues such as liver and immune cells in the circulation, with also potential effects on other tissues such as adipose. The susceptibility of the animal to develop mastitis likely is affected by factors beyond the mammary gland, e.g. negative energy balance as it occurs around parturition. Objectives of this review are to discuss the use of systems biology concepts for the holistic study of animal responses to intramammary infection; providing an update of recent work using transcriptomics to study mammary and peripheral tissue (i.e. liver) as well as neutrophils and macrophage responses to mastitis-causing pathogens; discuss the effect of negative energy balance on mastitis predisposition; and analyze the bovine and murine mammary innate-immune responses during lactation and involution using a novel functional analysis approach to uncover potential predisposing factors to mastitis throughout an animal's productive life.

Effects of energy balance on postprandial triacylglycerol metabolism

To present the effect of negative energy balance on postprandial triacylglycerol concentrations (pTAG), an independent risk factor for the development of cardiovascular disease. Aerobic exercise reduces pTAG; however, recent findings confirm that this effect is only evident with an accompanying energy deficit. Moreover, a recent study showed that acute diet-induced energy deficit also reduces pTAG. The extent of energy deficit required to significantly attenuate pTAG depends on the type of given meal, the type of deficit (aerobic/resistance exercise, diet, or combination of diet and exercise), and patients' health status. Apart from the acute effects, prolonged energy deficit leading to moderate weight loss attenuates pTAG, when it is combined with other known hypotriacylglycerolemic agents, such as carbohydrate restriction. For healthy population, it seems that it is up to patient's preference and ability which type of energy deficit will follow to attenuate pTAG; an energy deficit of approximately 30 kJ/kg of body mass is required; for resistance exercise a smaller deficit is probably sufficient. More studies are needed to investigate dose-response/plateau effects, the effects of energy deficit-energy surplus every other day, and the threshold of energy deficit-weight loss in diabetics and other high-risk populations. Finally, investigation of the underlying mechanisms may be clinicall helpful in individualizing the appropriate intervention.

Effect of negative energy balance on the insulin-like growth factor system in pre-recruitment ovarian follicles of post partum dairy cows

Post partum negative energy balance (NEB) in dairy cattle is associated with a delayed return to ovarian cyclicity and reduced fertility. This study compared the IGF system of pre-recruitment ovarian follicles between cows in mild (n = 6) or severe (n = 6) NEB during early lactation. Ovaries were collected in the second week post partum, when circulating concentrations of IGF-I and glucose were lower (P < 0.01) in severe NEB cows. mRNA expression for IGF-II, type 1 IGF receptor (IGF-1R) and IGF-binding proteins (IGFBP)-1 to IGFBP-6 was determined by in situ hybridisation in individual follicles using radiolabelled oligonucleotide probes. Follicles were classified as very small (1-2.5 mm) or small (2.5-5 mm) and healthy or atretic. Relative mRNA concentrations were measured as optical density (OD) units using image analysis. Thecal IGF-II mRNA expression was highest in very small, healthy follicles (P < 0.05). Granulosa cell IGFBP-2 was the only component to change with EB status, with higher mRNA expression in mild compared with severe NEB cows (P < 0.05). IGFBP-1 and IGFBP-3 mRNA expression were undetectable. IGF-1R, IGFBP-4 and IGFBP-5 mRNA expression were not significantly altered by follicle size or health, but IGFBP-5 tended to increase in atretic follicles. The pattern of IGFBP-6 mRNA expression in theca paralleled that of IGF-II mRNA, with higher (P < 0.05) levels in healthy, very small follicles. In conclusion, the reduced expression of IGFBP-2 mRNA in severe NEB cows may alter the bioavailability of circulating IGF-I and locally produced IGF-II to modulate the pre-recruitment stages of follicles required to maintain normal post partum ovarian cyclicity.

Postpartum resumption of cyclic ovarian function, first estrus and re-conception and their relation to energy metabolism in high-producing dairy cows

In the last few decades a continuous increase was observed in average milk production of dairy cows all over the world. Simultaneously, however, a dramatic decrease was seen in reproductive performance. This tendency is attributed to the increased incidence of bacterial complications in uterine involution, as well as to the high occurrence of ovarian malfunctions in the postpartum period. The aim of this paper is to review the physiology and pathology of the latter, really complex phenomenon. The nutritional basis of this process, that the requirements of high-producing dairy cows shift abruptly after parturition as the daily milk yield rapidly increases and the ensuing negative energy balance (NEB) will extend 10-12 weeks. In the context of the high genetic merit dairy cow, the pp NEB is the difference between the dietary intake of utilizable energy and the expenditure of energy for body mass maintenance and milk synthesis. In principle, it is a physiological phenomenon, which may, however, result in more or less severe disorders in both the metabolism and reproduction and so it may lead to great economic losses in modern dairy practice [112]. In the first 3-4 weeks after calving the NEB is highly correlated with both milk yield and the interval to first ovulation. Because the number of ovulatory estrous cycles preceding the insemination (AI) has been shown to influence the conception rate, the length of the pp interval to first ovulation provides an important parameter for assessing the effect of NEB on reproductive performance S19, 20?.

Event-time analysis of the effect of season of parturition, parity, and concurrent disease on parturition-to-conception interval in dairy cows

Abstract Objective To quantify the effect of season of parturition, parity, and various diseases on time to conception. Design Event-time analysis (survival analysis). Sample Population 44,450 cows delivering calves between September 1985 and September 1986, from 6,227 Ayrshire dairy herds in 80 Finnish communities. Procedure Primiparous and multiparous cows were analyzed in separate Cox proportional hazards models for postpartum days 56 to 120. Occurrence of 43 diseases or disorders was recorded; codes were condensed into 25 variables offered to each model. Season of parturition was categorized into spring, summer, and fall-winter; for multiparous cows, 3 categorical variables represented parity. Models controlled for 60-day milk and milk fat production, herd milk production, and community. For all observations, parturition-to-conception interval was plotted against calendar day of parturition. Results For multiparous cows, parturition in the spring or summer and being of parity 2 or 3-4 (vs older) increased the chance of conceiving; 10 diseases or disorders decreased this probability. Similarly, in the model for primiparae, parturition in spring or summer increased the probability of conception, and 6 disorders decreased it. Disorders that were detrimental in both models were anestrus, ovulatory dysfunction, other infertility, late metritis, and clinical ketosis. Conclusions The effect of season on the parturition- to-conception interval was marked at this latitude. Parturition during late April, causing confluence of postpartum day 55 with the summer solstice, was associated with the shortest parturition-to-conception intervals. Ketosis was found to be an important factor in lengthening the parturition-to-conception interval, highlighting the effect of negative energy balance on postpartum restoration of reproductive function. (Am J Vet Res 1996; 57:640–645)

Effect of Dietary Energy Restriction on the Expression of Insulin-like Growth Factor-I in Liver and Corpus Luteum of Heifers

The effects of energy balance on the corpus luteum may be mediated by IGFI-I. Our objective was to determine whether negative energy balance decreases expression of IGF-I mRNA in the liver or corpus luteum of heifers. For four consecutive estrous cycles, 14 Holstein heifers were maintained in negative or positive energy balance to lose 510 g/d of BW or gain 560 g/d of BW, respectively. The liver was biopsied and the corpus luteum was collected 7 d after fourth estrus. Heifers fed below maintenance had a smaller corpus luteum than did control heifers. Compared with that of controls, negative energy balance increased growth hormone in serum but decreased IGF-I in serum and the abundance of mRNA for growth hormone receptor and IGF-I in liver. In contrast, diet did not affect the abundance of mRNA for the growth hormone receptor or IGF-I in luteal tissue. Negative energy balance increased IGF binding protein-2 in serum but did not affect IGF binding protein-3. We conclude that negative energy balance of cattle decreases IGF-I mRNA abundance in the liver but not in the 7-d corpus luteum. If decreased IGF-I mediates the adverse effect of negative energy balance on luteal growth, the mode of action is likely endocrine, not autocrine or paracrine.