Effect of feed restriction on serum somatotropin, insulin-like growth factor-I-(IGF-I) and IGF binding proteins in cyclic heifers actively immunized against growth hormone releasing factor

Armstrong, Jeffrey D.; Cohick, Wendie S.; Harvey, R. W.; Heimer, Edgar P.; Campbell, Robert M.

doi:10.1016/0739-7240(93)90035-a

Cited by 31 publications

(12 citation statements)

References 37 publications

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“…Nutrient intake after calving influenced concentrations of IGF-I in plasma of primiparous lactating beef cows. This is consistent with previous studies in which concentrations of IGF-I in plasma were directly related to nutrient intake in heifers (Armstrong et al, 1993;Yelich et al, 1996;Armstrong et al, 2001), primiparous (Lalman et al, 2000), and mature (Richards et al, 1991) beef cows. Reduced nutrient intake uncouples the GH-IGF-I axis (Thissen et al, 1994).…”

Section: Discussionsupporting

confidence: 93%

Influence of body condition at calving and postpartum nutrition on endocrine function and reproductive performance of primiparous beef cows1,2

Ciccioli

Wettemann

Spicer

et al. 2003

Journal of Animal Science

185

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The influences of body condition score (BCS) at calving and postpartum nutrition on endocrine and ovarian functions, and reproductive performance, were determined by randomly allocating thin (mean BCS = 4.4 +/- 0.1) or moderate condition (mean BCS = 5.1 +/- 0.1) Angus x Hereford primiparous cows to receive one of two nutritional treatments after calving. Cows were fed to gain either 0.45 kg/d (M, n = 17) or 0.90 kg/d (H, n = 17) for the first 71 +/- 3 d postpartum. All cows were then fed the M diet until 21 d after the first estrus. A replication (yr 2; M, n = 25; H, n = 23) was also used to evaluate reproductive characteristics. Concentrations of IGF-I, leptin, insulin, glucose, NEFA, and thyroxine were quantified in plasma samples collected weekly during treatment and during 7 wk before the first estrus. Estrous behavior was detected by radiotelemetry, and luteal activity was determined based on concentrations of progesterone in plasma. All cows were bred by AI between 14 and 20 h after onset of estrus, and pregnancy was assessed at 35 to 55 d after AI by ultrasonography. Cows that calved with a BCS of 4 or 5 had similar endocrine function and reproductive performance at the first estrus. During treatment, H cows gained BW and increased BCS (P < 0.01), and had greater (P < 0.05) concentrations of IGF-I, leptin, insulin, glucose, and thyroxine in plasma than M cows. However, during the 7 wk before the first estrus, plasma concentrations of IGF-I, leptin, insulin, glucose, NEFA, and thyroxine were not affected by time. Cows previously on the H treatment had a shorter (P < 0.01) interval to first postpartum estrus and ovulation, and a larger dominant follicle (P < 0.01) at first estrus, than M cows, but duration of estrus and the number of mounts received were not influenced by nutrient intake. Pregnancy rate at the first estrus was greater (P < 0.03) for H (76%, n = 38) than for M (58%, n = 33) cows. Increased nutrient intake after calving stimulated secretion of anabolic hormones, promoted fat deposition, shortened the postpartum interval to estrus, and increased pregnancy rate at the first estrus. Concentrations of IGF-I and leptin in plasma were constant during 7 wk before the first estrus, indicating that acute changes in these hormones are not associated with the resumption of ovarian function in primiparous beef cows.

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Section: Discussionsupporting

confidence: 93%

Influence of body condition at calving and postpartum nutrition on endocrine function and reproductive performance of primiparous beef cows1,2

Ciccioli

Wettemann

Spicer

et al. 2003

Journal of Animal Science

185

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“…Dry matter intake is typically reduced in ruminants consuming EI (Paterson et al, 1995;Looper et al, 2007). Nutrient restriction uncouples the positive relationship of the GH-IGF axis with increased concentrations of GH and reduced IGF-I (Armstrong et al, 1993). Similar to concentrations of PRL, IGF-I was diminished in marginal-BC cows grazing EI, and this group of cows had the least calving rate of all cow groups in this experiment.…”

Section: Discussionmentioning

confidence: 69%

Effects of body condition on measures of intramuscular and rump fat, endocrine factors, and calving rate of beef cows grazing common bermudagrass or endophyte-infected tall fescue1,2

Looper

Reiter

Williamson

et al. 2010

Journal of Animal Science

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Multiparous beef cows were managed to achieve marginal (BCS = 4.7 ± 0.07; n = 106) or good (BCS = 6.6 ± 0.06; n = 121) body condition (BC) to determine the influence of forage environment on BW and BC changes, intramuscular fat percentage (IMF), rump fat (RF), and serum hormones during 2 yr. Cows within each BC were randomly assigned to graze either common bermudagrass (CB; n = 3 pastures/yr) or toxic endophyte-infected tall fescue (EI; n = 3 pastures/yr) during a 60-d breeding season. Blood samples were collected at d 0, 30, and 60 of the breeding season, and serum concentrations of prolactin (PRL), IGF-I, and cortisol (CORT) were quantified; PRL and progesterone (P(4)) also were quantified 10 d before the breeding season (d -10). Body weight and BCS were recorded during the breeding season (d 0, 30, and 60). Cow IMF and RF were measured via ultrasonography at the start and end of the breeding season. Cows with increased (>1 ng/mL) P(4) at the beginning of the breeding season (cyclic) had greater (P < 0.02) concentrations of PRL on d 30 and 60 compared with anestrous cows. A forage environment × BC interaction tended (P = 0.07) to influence PRL. Cows grazing CB independent of BC had increased PRL compared with cows grazing EI. Prolactin was decreased in good-BC cows grazing EI compared with cows grazing CB, and cows in marginal BC grazing EI had the least concentrations of PRL. Concentrations of IGF-I were similar (P > 0.10) among good- and marginal-BC cows grazing CB, as well as good-BC cows grazing EI; however, marginal-BC cows grazing EI had reduced (P < 0.04) concentrations of IGF-I compared with all other groups. Cows in marginal BC grazing CB gained (P = 0.02) the most BW during the breeding season, whereas good-BC cows grazing EI gained the least amount of BW. Marginal-BC cows grazing CB tended (P = 0.06) to increase BC during the breeding season, whereas good-BC cows grazing either CB or EI lost BC. Rump fat tended (P = 0.07) to increase during the breeding season in marginal-BC cows compared with cows in good BC. Calving rates were similar (P > 0.10) among good- (82%) and marginal- (84%) BC cows grazing CB, and good-BC cows grazing EI (79%); however, marginal-BC cows grazing EI had a reduced (P = 0.04) calving rate (61%). Cattle grazing EI during the breeding season lost BC. That reduction in BC may be communicated to the pituitary via hormones that include IGF-I or PRL or both, resulting in decreased calving rates.

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“…Note that adding IGF-2 in excess, as done in commercially available human IGF-1 immunoassays, improved neither the normalized standard curves nor the detection of biomarker level differences in between treated and untreated animals. The developed assay showed high reproducibility for all measured candidate biomarkers (Table 2) and a comparable sensitivity to previous single biomarker methods [35], [36]. However, the newly developed 4-plex FCIA has several advantages, such as the simultaneous measurement of all four markers in one sample from one well of a microtiter plate, which saves sample material, work load and time.…”

Section: Resultsmentioning

confidence: 86%

Multiple Protein Biomarker Assessment for Recombinant Bovine Somatotropin (rbST) Abuse in Cattle

Ludwig¹,

Smits²,

Veer³

et al. 2012

PLoS ONE

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Biomarker profiling, as a rapid screening approach for detection of hormone abuse, requires well selected candidate biomarkers and a thorough in vivo biomarker evaluation as previously done for detection of growth hormone doping in athletes. The bovine equivalent of growth hormone, called recombinant bovine somatotropin (rbST) is (il)legally administered to enhance milk production in dairy cows. In this study, first a generic sample pre-treatment and 4-plex flow cytometric immunoassay (FCIA) were developed for simultaneous measurement of four candidate biomarkers selected from literature: insulin-like growth factor 1 (IGF-1), its binding protein 2 (IGFBP2), osteocalcin and endogenously produced antibodies against rbST. Next, bovine serum samples from two extensive controlled rbST animal treatment studies were used for in vivo validation and biomarker evaluation. Finally, advanced statistic tools were tested for the assessment of biomarker combination quality aiming to correctly identify rbST-treated animals. The statistical prediction tool k-nearest neighbours using a combination of the biomarkers osteocalcin and endogenously produced antibodies against rbST proved to be very reliable and correctly predicted 95% of the treated samples starting from the second rbST injection until the end of the treatment period and even thereafter. With the same biomarker combination, only 12% of untreated animals appeared false-positive. This reliability meets the requirements of Commission Decision 2002/657/EC for screening methods in veterinary control. From the results of this multidisciplinary study, it is concluded that the osteocalcin – anti-rbST-antibodies combination represent fit-for-purpose biomarkers for screening of rbST abuse in dairy cattle and can be reliably measured in both the developed 4-plex FCIA as well as in a cost-effective 2-plex microsphere-based binding assay. This screening method can be incorporated in routine veterinary monitoring programmes: in the European Union for detection of rbST abuse and in the control of rbST-free dairy farms in the United States of America and other countries.

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Effect of feed restriction on serum somatotropin, insulin-like growth factor-I-(IGF-I) and IGF binding proteins in cyclic heifers actively immunized against growth hormone releasing factor

Abstract: Feed restriction often increases serum somatotropin (ST) and decreases insulin-like growth fac tor-I (IGF-I) in ruminants; however, the mechanisms responsible for this change in ST and IGF-I are not well defined. We investigated the effects of feed restriction on serum ST, IGF

Cited by 31 publications

References 37 publications

Influence of body condition at calving and postpartum nutrition on endocrine function and reproductive performance of primiparous beef cows1,2

Influence of body condition at calving and postpartum nutrition on endocrine function and reproductive performance of primiparous beef cows1,2

Effects of body condition on measures of intramuscular and rump fat, endocrine factors, and calving rate of beef cows grazing common bermudagrass or endophyte-infected tall fescue1,2

Multiple Protein Biomarker Assessment for Recombinant Bovine Somatotropin (rbST) Abuse in Cattle

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