Nutritional influences on breeding dynamics in elk

2001 ◽  
Vol 79 (5) ◽  
pp. 845-853 ◽  
Author(s):  
Rachel C Cook ◽  
Dennis L Murray ◽  
John G Cook ◽  
Peter Zager ◽  
Steven L Monfort

Nutrition in summer and early autumn may influence pregnancy rates and recruitment in ungulate herds in temperate regions, yet this influence on the reproductive endocrinology of wild ungulates is poorly understood. We examined the effects of 3 levels of summer–autumn nutrition on timing of breeding, pregnancy rates, and concentration of fecal progestagens (P4) in 30 captive female elk (Cervus elaphus nelsoni). Digestible energy (DE) content for females on the high-nutrition treatment was maintained at 12.35 kJ/g, while DE content for females on the medium- and low-nutrition treatments was gradually reduced to 10.89 and 9.42 kJ/g, respectively, by the end of the breeding season (all feed was offered ad libitum) to mimic the natural decline in forage quality during summer and autumn. In addition, we used three females as a control; they were maintained on a high-nutrition diet and kept separate from a bull. Based on fecal P4 concentrations and visual observations, 90, 90, and 10% of the elk on the high-, medium-, and low-nutrition treatments bred, respectively. Nutritional restriction delayed breeding by an average of 8 and 28 days in the medium- and low-nutrition animals. Females in the low- and medium-nutrition treatments excreted significantly higher P4 concentrations prior to breeding than did animals in the high-nutrition treatment. Diet failed to affect P4 concentration during pregnancy, but we found evidence that P4 concentrations were positively correlated with body condition (ingesta-free body fat content) during early gestation. Females that did not breed failed to exhibit estrous behavior, and hormone-excretion profiles confirmed that these animals failed to ovulate. These results suggest that inadequate nutrition in summer and autumn reduce pregnancy rates by preventing estrus and ovulation rather than by inducing early-embryo mortality.

2009 ◽  
Vol 123 (3) ◽  
pp. 230 ◽  
Author(s):  
Jessica R. Piasecke ◽  
Louis C. Bender ◽  
Stephen M. Schmitt

Uncertainty exists as to which factors are most closely related to probability of pregnancy in Elk (Cervus elaphus), which thresholds are key for managers who want to assess the potential productivity of free-ranging Elk herds, and whether these thresholds vary among populations. We examined relationships among pregnancy, age, and mass for 513 harvested free-ranging Elk in Michigan, and compared relationships with other published models and with thresholds derived from other free-ranging and penned populations to see if relationships were consistent among populations. Pregnancy rates varied (chi22 = 136.3; P < 0.0001) among yearling (0.30), prime-aged (2.5-11.5-year-olds; 0.88), and old (> 12.5-year-olds; 0.60) cows. Probability of pregnancy in adult cows was related to mass (chi2 = 7.4; P = 0.006), age (chi2 = 12.6; P = 0.0004) and age class (chi2 = 16.4; P < 0.0001), but not to lactation status (chi2 = 0.4; P = 0.515); pregnancy was also positively related (chi2 = 15.8; P < 0.0001) to mass in yearlings. Probability of pregnancy increased 1.02× and 1.04× for each 1 kg increase in body mass of adult and yearling cows, respectively, and prime-aged cows were 4.9× more likely to conceive than old cows. Compared to thresholds derived primarily from penned or farmed Elk, both adult and yearling free-ranging Elk in Michigan and elsewhere were able to achieve higher levels of pregnancy at lower body mass. Thresholds also varied among free-ranging Elk populations. Given variation among populations, managers should calibrate mass-pregnancy relationships for their respective populations to determine whether condition is potentially limiting pregnancy in their populations.


2007 ◽  
Vol 3 (1) ◽  
Author(s):  
M. P. O. Olsson ◽  
J. Cox ◽  
J. Larkin ◽  
D. Maehr ◽  
P. Widén ◽  
...  

2012 ◽  
Vol 24 (1) ◽  
pp. 29 ◽  
Author(s):  
Linda L.-Y. Wu ◽  
Robert J. Norman ◽  
Rebecca L. Robker

Obesity can have detrimental effects on pregnancy rates in natural conceptions and also in women undergoing IVF or intracytoplasmic sperm injection (ICSI). This review summarises the most recent clinical literature investigating whether obesity impacts oocyte quality and early embryo growth. In other tissues, obesity leads to lipotoxicity responses including endoplasmic reticulum stress, mitochondrial dysfunction and apoptosis. Recent reports indicate that lipotoxicity is a mechanism by which obesity may impact oocyte quality.


2020 ◽  
Vol 32 (2) ◽  
pp. 130
Author(s):  
M. Oliveira ◽  
R. Santos ◽  
R. Chebel ◽  
D. Demetrio

Excessive heat affects the fertility of high production lactating cows, and reduced pregnancy rates (PR) are observed during summer and early fall. Embryo production programs are used to produce more calves from high genetic merit animals, but could it also increase fertility by bypassing all the negative variables affecting the embryo development before Day 7 (oocyte development, ovulation, fertilization, early embryo development)? The data from AIs and embryo transfers (ET) between June 2017 and May 2019 were analysed. June, July, August, September, and October were called critical months (first-service AI conception rate dropped below 44%). The cows were located at Maddox Dairy in Riverdale, CA, USA, a Holstein herd that milks 3500 cows with a 305-day mature-equivalent milk production of 12 800 kg. First- and second-lactation cows were enrolled in a Presynch-Ovsynch oestrus-synchronization program and scheduled for the first AI at 86 days after calving or to receive an embryo 7 or 8 days after the expected heat. The embryos were produced invivo or invitro from Holstein donors and were transferred fresh or frozen. Blood was sampled on Day 30 after expected heat day (23 days after embryo transfer), and pregnancy was detected by the IDEXX PAG Bovine Pregnancy Test. Table 1 summarises the results, where ET PR% is the number of pregnant cows divided by the number of cows that received and embryo. All the cows synchronized for AI were bred, but only cows with the presence of a corpus luteum (CL) on ET day received an embryo. The presence of a CL was not detected in 28.7% (471/1642) of the cows (32.2% in the critical months and 25.7% in the others). Unfortunately, we could not detect the presence of a CL by ultrasonography every time we transferred embryos, so the nonovulation rate might be overestimated. The cows without a CL were considered open and used to calculate the adjusted PR (AdjPR%). Embryo transfer PR is superior to that of AI, especially during the critical months. Fresh invivo embryos have the most impact. When the cows without CLs are considered open, the difference between AI and ET is still evident for fresh invivo embryos. Besides producing animals with higher genetic merit, depending on the type of embryo used, ET can increase fertility in lactating Holstein cows, especially during the critical months. The other benefit of using ET is that cows that do not ovulate are synchronized right away, which is not the case for AI cows. Table 1.AI×embryo transfer in lactating Holstein cows1 from June 2017 to May 20192 Item Critical months (June to October) Other months (November to May) All year %PR n Adj PR% n %PR n Adj PR% n %PR n Adj PR% n Artificial insemination 41.2% 896 41.2% 896 47.7% 1767 47.7% 1767 45.5% 2663 2663 Fresh invivo embryo 62.7% 373 47.5% 493 69.5% 262 55.3% 329 65.5% 635 50.6% 822 Frozen invivo embryo 59.3% 221 44.8% 292 59.4% 256 47.3% 322 59.3% 477 46.1% 614 IVF fresh embryo 47.9% 167 36.2% 221 54.0% 363 43.0% 456 52.1% 530 40.8% 677 Total embryos 58.5% 761 44.2% 1006 60.2% 881 47.9% 1107 59.4% 1642 46.1% 2113 1Lactating Holstein cows, first and second lactation, first service, Presynch-Ovsynch, 85 DIM. 2PR%=the number of pregnant cows divided by the number of cows that received and embryo; AdjPR%=adjusted pregnancy rate.


2013 ◽  
Vol 49 (2) ◽  
pp. 270-278 ◽  
Author(s):  
Ryan J. Monello ◽  
Jenny G. Powers ◽  
N. Thompson Hobbs ◽  
Terry R. Spraker ◽  
Katherine I. O’Rourke ◽  
...  

1990 ◽  
Vol 51 (3) ◽  
pp. 613-621 ◽  
Author(s):  
P. F. Fennessy ◽  
C. G. Mackintosh ◽  
G. H. Shackell

ABSTRACTSix experiments involving the artificial insemination (AI) of a total of 300 female red deer (hinds) with frozen-thawed red deer semen (collected by electro-ejaculation) were conducted over 3 years. Insemination took place at fixed times following various oestrous synchronization procedures using progesterone withdrawal and treatment with pregnant mare's serum gonadotropin (PMSG). In the 1st year, the experiments evaluated basic AI techniques in which pregnancy rates were 45% in 20 hinds receiving two inseminations per vaginam (PV) and 56% in 27 hinds inseminated by the laparoscopic intrauterine method (IU). In the 2nd year, the experiments involved comparisons of the progesterone regime, one or two PV inseminations, and the timing of a single PV insemination. There was no effect of replacement of the progesterone device after 9 days and withdrawal 3 days later compared with the use of one device for the whole period in two experiments. The pregnancy rate for a double PV insemination was significantly higher than for a single PV insemination (58 and 34%; P < 0·05) and there was also a small effect of timing of insemination relative to the synchronization treatment. In the 3rd year all hinds were inseminated by the IU method. The experiments involved a comparison of various times of AI following progesterone withdrawal and a comparison of the progesterone regime. The overall pregnancy rate for 63 hinds inseminated was 56% with no difference between three times of insemination (48, 52 and 55 h). In the second experiment, the difference in pregnancy rate between treatment with progesterone for 15 days and 12 days (44 and 72% for 18 hinds per group) was not significant, but the interaction between the length of progesterone treatment and insemination time was significant (P < 0·05), with the 12-day progesterone/55 h insemination giving a much higher pregnancy rate than the 15-day/55 h insemination (89 and 20% respectively). Although no experiments involved direct comparisons of the routes of insemination, overall pregnancy rates were 56% for IU, 53% for double PV and 35% for single PV inseminations.


1995 ◽  
Vol 32 (3) ◽  
pp. 215-220 ◽  
Author(s):  
J. C. Rhyan ◽  
D. A. Saari

Sections of tuberculous lesions from 23 elk ( Cervus elaphus nelsoni) and red deer ( Cervus elaphus elaphus), 12 fallow deer ( Dama dama), 10 sika deer ( Cervus nippon), and 30 cattle were examined and compared. Lesions were scored for caseous necrosis, mineralization, neutrophils, macrophages, giant cells, and acid-fast bacilli. Some differences in lesion morphology between the species were noted. Elk/red deer lesions had marked variation and often differed from bovine lesions in several characteristics; elk/red deer lesions usually had scattered peripheral mineralization rather than central mineralization and contained more neutrophils and fewer giant cells than did bovine lesions. Fallow deer lesions contained more giant cells but were otherwise indistinguishable from elk lesions. Sika deer lesions had more giant cells and fewer neutrophils than did lesions from cattle or other cervid species. Sika deer giant cells were larger and contained more nuclei than did giant cells in the other species.


2008 ◽  
Vol 89 (5) ◽  
pp. 1324-1328 ◽  
Author(s):  
Matteo Perucchini ◽  
Karen Griffin ◽  
Michael W. Miller ◽  
Wilfred Goldmann

Variation in PrP prion gene sequence appears to modulate susceptibility to chronic wasting disease (CWD), a naturally occurring prion disease affecting four North American species of the family Cervidae. Wapiti (Cervus elaphus nelsoni) PrP is polymorphic at codon 132 [methionine (M) or leucine (L)]. We genotyped 171 samples, collected between 2002 and 2005 from CWD-infected and uninfected wapiti from three free-ranging populations in Colorado, USA, to study influences of PrP polymorphisms on CWD susceptibility further. Overall genotype frequencies for 124 apparently uninfected animals were 65.3 % MM132, 32.3 % ML132 and 2.4 % LL132; for 47 CWD-infected animals, these frequencies were 70.2 % MM132, 27.7 % ML132 and 2.1 % LL132. Surprisingly, our data revealed that, among recent (approx. 2002–2005) CWD cases detected in free-ranging Colorado wapiti, the three PrP codon 132 genotypes were represented in proportion to their abundance in sampled populations (P≥0.24) and all three genotypes showed equivalent susceptibility to infection.


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