Linking population performance to nutritional condition in an alpine ungulate

Abstract Bighorn sheep (Ovis canadensis) can live in extremely harsh environments and subsist on submaintenance diets for much of the year. Under these conditions, energy stored as body fat serves as an essential reserve for supplementing dietary intake to meet metabolic demands of survival and reproduction. We developed equations to predict ingesta-free body fat in bighorn sheep using ultrasonography and condition scores in vivo and carcass measurements postmortem. We then used in vivo equations to investigate the relationships between body fat, pregnancy, overwinter survival, and population growth in free-ranging bighorn sheep in California and Nevada. Among 11 subpopulations that included alpine winter residents and migrants, mean ingesta-free body fat of lactating adult females during autumn ranged between 8.8% and 15.0%; mean body fat for nonlactating females ranged from 16.4% to 20.9%. In adult females, ingesta-free body fat > 7.7% during January (early in the second trimester) corresponded with a > 90% probability of pregnancy and ingesta-free body fat > 13.5% during autumn yielded a probability of overwinter survival > 90%. Mean ingesta-free body fat of lactating females in autumn was positively associated with finite rate of population increase (λ) over the subsequent year in bighorn sheep subpopulations that wintered in alpine landscapes. Bighorn sheep with ingesta-free body fat of 26% in autumn and living in alpine environments possess energy reserves sufficient to meet resting metabolism for 83 days on fat reserves alone. We demonstrated that nutritional condition can be a pervasive mechanism underlying demography in bighorn sheep and characterizes the nutritional value of their occupied ranges. Mountain sheep are capital survivors in addition to being capital breeders, and because they inhabit landscapes with extreme seasonal forage scarcity, they also can be fat reserve obligates. Quantifying nutritional condition is essential for understanding the quality of habitats, how it underpins demography, and the proximity of a population to a nutritional threshold.

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Impact of Mycoplasma ovipneumoniae on juvenile bighorn sheep (Ovis canadensis) survival in the northern Basin and Range ecosystem

PeerJ ◽

10.7717/peerj.10710 ◽

2021 ◽

Vol 9 ◽

pp. e10710

Author(s):

Robert S. Spaan ◽

Clinton W. Epps ◽

Rachel Crowhurst ◽

Donald Whittaker ◽

Mike Cox ◽

...

Keyword(s):

Genetic Diversity ◽

Genetic Variation ◽

Survival Probability ◽

Population Genetic ◽

Bighorn Sheep ◽

Basin And Range ◽

Ovis Canadensis ◽

Juvenile Survival ◽

Adult Females ◽

Mycoplasma Ovipneumoniae

Determining the demographic impacts of wildlife disease is complex because extrinsic and intrinsic drivers of survival, reproduction, body condition, and other factors that may interact with disease vary widely. Mycoplasma ovipneumoniae infection has been linked to persistent mortality in juvenile bighorn sheep (Ovis canadensis), although mortality appears to vary widely across subspecies, populations, and outbreaks. Hypotheses for that variation range from interactions with nutrition, population density, genetic variation in the pathogen, genetic variation in the host, and other factors. We investigated factors related to survival of juvenile bighorn sheep in reestablished populations in the northern Basin and Range ecosystem, managed as the formerly-recognized California subspecies (hereafter, “California lineage”). We investigated whether survival probability of 4-month juveniles would vary by (1) presence of M. ovipneumoniae-infected or exposed individuals in populations, (2) population genetic diversity, and (3) an index of forage suitability. We monitored 121 juveniles across a 3-year period in 13 populations in southeastern Oregon and northern Nevada. We observed each juvenile and GPS-collared mother semi-monthly and established 4-month capture histories for the juvenile to estimate survival. All collared adult females were PCR-tested at least once for M. ovipneumoniae infection. The presence of M. ovipneumoniae-infected juveniles was determined by observing juvenile behavior and PCR-testing dead juveniles. We used a known-fate model with different time effects to determine if the probability of survival to 4 months varied temporally or was influenced by disease or other factors. We detected dead juveniles infected with M. ovipneumoniae in only two populations. Derived juvenile survival probability at four months in populations where infected juveniles were not detected was more than 20 times higher. Detection of infected adults or adults with antibody levels suggesting prior exposure was less predictive of juvenile survival. Survival varied temporally but was not strongly influenced by population genetic diversity or nutrition, although genetic diversity within most study area populations was very low. We conclude that the presence of M. ovipneumoniae can cause extremely low juvenile survival probability in translocated bighorn populations of the California lineage, but found little influence that genetic diversity or nutrition affect juvenile survival. Yet, after the PCR+ adult female in one population died, subsequent observations found 11 of 14 ( 79%) collared adult females had surviving juveniles at 4-months, suggesting that targeted removals of infected adults should be evaluated as a management strategy.

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Identification of novel variants of interferon-tau gene in Bighorn sheep (Ovis canadensis mexicana), Pelibuey sheep (Ovis aries) and its expression in hybrid blastocysts (Ovis canadensis × Ovis aries)

Canadian Journal of Animal Science ◽

10.4141/cjas2011-023 ◽

2012 ◽

Vol 92 (3) ◽

pp. 275-283 ◽

Cited By ~ 1

Author(s):

M. Palma-Irizarry ◽

P. Damian-Matsumura ◽

M. Betancourt ◽

S. Romo ◽

G. Perales ◽

...

Keyword(s):

Bighorn Sheep ◽

Ovis Canadensis ◽

Ovis Aries ◽

Domestic Sheep ◽

Interferon Tau ◽

Pelibuey Sheep ◽

Novel Variants ◽

Ovis Canadensis Mexicana

Palma-Irizarry, M., Damian-Matsumura, P., Betancourt, M., Romo, S., Perales, G., Lagunas-Martínez, A., Madrid-Marina, M. V., Mejía, O. and Ducolomb, Y. 2012. Identification of novel variants of interferon-tau gene in Bighorn sheep ( Ovis canadensis mexicana ), Pelibuey sheep ( Ovis aries ) and its expression in hybrid blastocysts ( Ovis canadensis×Ovis aries ). Can. J. Anim. Sci. 92: 275–283. The major signal for maternal recognition of pregnancy (MRP) in ruminants is interferon-tau (IFNT). Four novel sequences of the IFNT gene were isolated from genomic DNA obtained from blood samples of Bighorn, Pelibuey or the hybrid ewes. The deduced amino acid sequence of the hybrid ewe showed 100% identity with one Bighorn sheep IFNT sequence, suggesting that this sequence was inherited from Bighorn sheep. The high degree of identity between Pelibuey and Bighorn sheep sequences could be a possible explanation for the successful MRP in some Bighorn hybrid pregnancies. In vivo and in vitro domestic sheep (Ovis aries) and hybrid sheep (Ovis aries×Ovis canadensis) blastocysts were obtained, and IFNT expression was measured by semiquantitative RT-PCR. In vivo and in vitro hybrid blastocysts showed lower expression of IFNT when compared with domestic blastocysts. In conclusion this study showed that there exists an effect of hybridization on IFNT expression and this can affect the MRP.

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Pre- and Post-Slaughter Methodologies to Estimate Body Fat Reserves in Lactating Saanen Goats

Animals ◽

10.3390/ani11051440 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1440

Author(s):

Leonardo Sidney Knupp ◽

Mondina Francesca Lunesu ◽

Roberto Germano Costa ◽

Mauro Ledda ◽

Sheila Nogueira Ribeiro Knupp ◽

...

Keyword(s):

Body Weight ◽

Multiple Regression ◽

Body Fat ◽

Body Condition Score ◽

Regression Equations ◽

Dairy Goats ◽

Fat Reserves ◽

Fat Thickness ◽

Total Fat

This work aimed to compare pre- and post-slaughter methodologies to estimate body fat reserves in dairy goats. Twenty-six lactating Saanen goats ranging from 43.6 to 69.4 kg of body weight (BW) and from 1.84 to 2.96 of body condition score (BCS; 0–5 range) were used. Fifteen pre-slaughter and four post-slaughter measurement values were used to estimate the weight of fat in the omental (OM), mesenteric (MES), perirenal (PR), organ (ORG), carcass (CARC), and non-carcass components (NC) and total (TOT, calculated as the sum of CARC and NC) depots in goats. The pre-slaughter measurements were withers height; rump height; rump length; pelvis width; chest depth; shoulder width; heart girth; body length; sternum height; BW; BCS assessed in the lumbar (BCSl) and sternal (BCSs) regions; and fat thickness measured by ultrasound in the lumbar (FTUSl), sternal (FTUSs), and perirenal (FTUSpr) regions. The post-slaughter measurements were hot carcass weight (HCW), empty body weight (EBW), and fat thickness measured by digital caliper in the lumbar (FTDCl) and sternal (FTDCs) regions. Linear and multiple regressions were fit to data collected. BW, BCS (from lumbar and sternal regions), all somatic measurements, and fat thickness measured by ultrasound in the lumbar and sternal regions were not adequate to estimate the weight of total fat in lactating Saanen goats (R2 ≤ 0.55). The best pre-slaughter and post-slaughter estimators of OM, MES, PR, ORG, NC, and TOT fat were FTUSpr and EBW, respectively. Among pre- and post-slaughter measurements, BCSl (R2 = 0.63) and HCW (R2 = 0.82) provided the most accurate predictions of CARC fat, respectively. Multiple regression using the pre-slaughter variables FTUSpr, BW, and BCSl yielded estimates of TOT fat with an R2 = 0.92 (RSD = 1.14 kg). On the other hand, TOT fat predicted using the post-slaughter variables HCW and FTDCs had an R2 = 0.83 (RSD = 1.41 kg). These results confirm that fat reserves can be predicted in lactating Saanen goats with high precision using multiple regression equations combining in vivo measurements.

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Numbers of lungworm larvae in feces of bighorn sheep: yearly changes, influence of host sex, and effects on host survival

Canadian Journal of Zoology ◽

10.1139/z91-082 ◽

1991 ◽

Vol 69 (3) ◽

pp. 547-554 ◽

Cited By ~ 23

Author(s):

Marco Festa-Bianchet

Keyword(s):

Infection Intensity ◽

Bighorn Sheep ◽

Ovis Canadensis ◽

Seasonal Migration ◽

Herd Health ◽

Spring Precipitation ◽

Adult Females ◽

Host Sex ◽

Larval Count ◽

Study Population

The number of Protostrongylus spp. first-stage larvae in the feces of marked bighorn sheep (Ovis canadensis) was monitored from 1981 to 1988 in southwestern Alberta. Prevalence of infection was 100%. Counts were not correlated with spring precipitation, winter temperature, or number of female sheep in the study population. Percent lamb survival and average counts were correlated only when years affected by the occurrence of a pneumonia epizootic were excluded. In the years before the epizootic, but not afterwards, lambs born to females with high larval counts were less likely to survive to weaning or to 1 year of age than lambs born to females with low counts. Fecal larval counts from the same female in successive years were weakly correlated, and tended to change towards the mean for all females. Counts were affected by host reproduction but not by seasonal migration, and did not affect host survival. Among lambs and yearlings, males had higher counts than females. Lambs had higher counts than adult females. There were no age-specific differences among adult females. The larval count from female lambs was correlated with that from their mother but not that from male lambs. Heart girth of female lambs was correlated with their larval count and that of their mother. I suggest that larval counts are affected by infection intensity and body condition, do not predict pneumonia epizootics, and have limited reliability as an index of herd health.

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Habitat use and social mixing between groups of resident and augmented bighorn sheep

Scientific Reports ◽

10.1038/s41598-019-51370-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Rusty W. Robinson ◽

Jericho C. Whiting ◽

Justin M. Shannon ◽

Daniel D. Olson ◽

Jerran T. Flinders ◽

...

Keyword(s):

Habitat Use ◽

Species Conservation ◽

Source Area ◽

Bighorn Sheep ◽

Ovis Canadensis ◽

Range Use ◽

Adult Females ◽

Social Mixing ◽

Utilization Distributions ◽

Two Populations

Abstract Monitoring dispersal, habitat use, and social mixing of released ungulates is crucial for successful translocation and species conservation. We monitored 127 female bighorn sheep (Ovis canadensis) released in three populations from 2000 to 2009 to investigate if augmented bighorns expanded and shifted seasonal ranges, used different habitat compared with resident females, and if animals mixed socially. Augmented bighorns in all populations expanded range use compared with residents by shifting utilization distributions. Size of utilization distributions, however, were smaller for augmented females compared with residents in all areas except one. Overlap of seasonal utilization distributions between augmented and resident bighorns and use of slope and elevation differed across populations. In two populations, differences in size and overlap of seasonal utilization distributions and use of slope and elevation supported the hypothesis that habitat use of bighorns in their source area influenced their habitat use after release. Mixing between resident and augmented adult females occurred on average during only 21% of sightings and was similar across populations. Our results clarify how augmented bighorns mix with resident animals and how habitat use is modified following augmentations. Such information is needed to improve bighorn sheep augmentations and can be applied to augmentations of other ungulates.

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Body composition of the George River caribou (Rangifer tarandus caribou) in fall and late winter

Canadian Journal of Zoology ◽

10.1139/z89-016 ◽

1989 ◽

Vol 67 (1) ◽

pp. 103-107 ◽

Cited By ~ 22

Author(s):

J. Huot

Keyword(s):

Body Composition ◽

Body Fat ◽

Gravid Uterus ◽

Late Winter ◽

Pregnant Females ◽

Fat Reserves ◽

Body Weights ◽

Lactating Females ◽

Free Body ◽

George River

The fall and late winter body composition of George River caribou was determined based on a sample of 14 calves, 9 yearlings, and 41 adult females. In fall, the fattest individuals were the adult nonlactating females with 10.62 ± 2.65% ingesta-free body fat. Ingesta-free body fat was 5.25 ± 2.47% for lactating females, 7.76 ± 0.11% for yearlings, and 3.44 ± 0.57% for calves. There was no evidence of depletion of fat reserves between fall (October–December) and mid-April in any age-class, and no change in body weights of calves. However, the ingesta-free body weights of pregnant females in April were 19.8 and 9.5% less than those of nonlactating and lactating females in fall, respectively. These differences were due mainly to a loss of water (9.8 and 7.3 kg) and protein (4.6 and 2.6 kg). This protein loss of the ingesta-free body was not compensated for by growth of the gravid uterus, which accounted for 3.5% (0.53 kg) of the total protein mass of pregnant females in mid-April. These results suggest that, between fall and late winter, the George River caribou were affected more by a deficiency in protein than a negative energy budget and that increased attention should be given to monitor protein reserves. However, in summer and early fall, these caribou accumulated only limited fat reserves as compared with other northern ungulates and the possibility of an energy deficiency during summer should be investigated.

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