Growth in an Arctic Grazer: Effects of Sex and Dietary Nitrogen on Yearling Muskoxen

Peltier, T. C.; Barboza, Perry S.

doi:10.1644/bjk-102

Cited by 23 publications

(19 citation statements)

References 73 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We suggest further that this over-winter foraging period represents an energy-limiting time for juvenile seals beyond their first year of life. For many species, seasonal variation in growth patterns has been attributed to differences due to sex, age and physiological or reproductive state (Warrick & Cypher 1999, Beck et al 2003, Peltier & Barboza 2003, Veiberg et al 2004). All juvenile mammals need to reach a certain anatomical size and body condition to reproduce successfully, but the rate at which they do so may influence their age at primiparity, lifetime fecundity or the probability of survival (Post & Parkinson 2001, McMahon et al 2003.…”

Section: Discussionmentioning

confidence: 99%

Differential resource allocation strategies in juvenile elephant seals in the highly seasonal Southern Ocean

Field¹,

Bradshaw²,

Burton³

et al. 2007

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Environmental conditions experienced in early life affect growth and influence life history strategies, especially in seasonal environments. We studied the seasonal and sexual variation in resource allocation in juvenile southern elephant seals to investigate whether they show a seasonal decline in growth. We also examined whether sexual differences in growth may lead to separate growth strategies that suit each sex in maximizing fitness. We examined the variation in length (as a measure of somatic growth), body mass and condition of 470 individual 1-to 4-yr-old elephant seals relative to their different growth strategies. Applying a novel growth function, we observed increased somatic growth in summer compared to winter. Males were larger, had higher proportions of lean tissue and grew faster than females, demonstrating the evolution of a male growth strategy of attaining maximum size quickly, and a female strategy of achieving primiparity at an early age. This evidence supports the idea that seasonal patterns reflect seasonal variation in prey availability and quality, and differential growth strategies promote optimal resource allocation and increase an individual's probability of survival and future breeding success in the highly dynamic and seasonal Southern Ocean. KEY WORDS: Southern elephant seals · Resource allocation · Growth · Sexual dimorphism · Seasonal environmentResale or republication not permitted without written consent of the publisher

show abstract

Section: Discussionmentioning

confidence: 99%

Differential resource allocation strategies in juvenile elephant seals in the highly seasonal Southern Ocean

Field¹,

Bradshaw²,

Burton³

et al. 2007

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…Availability of high quality food in fall is critical to fat deposition for use during dormancy (Farley and Robbins 1995;Barboza et al 1997;Belant et al 2006). Protein intake in excess of nitrogen requirements may be able to be stored as lipids (Peltier and Barboza 2003), and bears have been shown to optimize the composition of gains in body mass (i.e., fat or lean body mass) when consuming mixed diets of varying protein content (Rode and Robbins 2000;Felicetti et al 2003b). In order to maintain larger sizes, males are likely to consume more meat than females.…”

Section: And In Yukon (Hayes and Harestad 2000)mentioning

confidence: 99%

Defining the predator landscape of northeastern British Columbia.

Milakovic¹

View full text Add to dashboard Cite

“…Brown fat in muskoxen is apparently depleted over the first few weeks postpartum (Adamczewski et al 1995). Under captive conditions, calves continue to grow through spring and summer, and by the onset of winter in October, they are normally around 70-80 kg body mass, or about one-third the size of adults (200-250 kg;Peltier and Barboza 2003;Knott et al 2005). Muskox calves enter their first winter with half the body fat content (percent body mass) of mature cows (Adamczewski et al 1995;Peltier and Barboza 2003).…”

Section: Winter: Small Calves Are Not At a Thermal Disadvantage Compamentioning

confidence: 99%

“…Under captive conditions, calves continue to grow through spring and summer, and by the onset of winter in October, they are normally around 70-80 kg body mass, or about one-third the size of adults (200-250 kg;Peltier and Barboza 2003;Knott et al 2005). Muskox calves enter their first winter with half the body fat content (percent body mass) of mature cows (Adamczewski et al 1995;Peltier and Barboza 2003). Small calves have higher ratios of surface area to volume (SA : vol) than adults and are therefore expected to lose heat more readily than adults with similar insulation.…”

Section: Winter: Small Calves Are Not At a Thermal Disadvantage Compamentioning

confidence: 99%

“…Additionally, cows and calves received a daily pelleted ration of milled grain and alfalfa with minerals and vitamins (Alaska Pet and Garden, Anchorage) at 200 and 100 g pellet air dry mass d Ϫ1 , respectively (Munn and Barboza 2008). The ration is a balanced supplement of minerals to grass hay (Peltier and Barboza 2003). Pellet rations were offered equivalent to 3.0 g dry matter kg Ϫ0.75 d Ϫ1 for the cows and calves and were always completely consumed.…”

Section: Animalsmentioning

confidence: 99%

See 1 more Smart Citation

Sensible Heat Loss from Muskoxen (Ovibos moschatus) Feeding in Winter: Small Calves Are Not at a Thermal Disadvantage Compared with Adult Cows

Munn¹,

Barboza²,

Dehn³

2009

Physiological and Biochemical Zoology

View full text Add to dashboard Cite

Dehn, J. (2009). Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows. Physiological and Biochemical Zoology, 82 (5), 455-467. Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows Abstract Muskoxen (Ovibos moschatus) are large (>200 kg adult body mass) mammalian herbivores that overwinter in the polar regions. Calves are around one-third the body mass of mature females and may be expected to suffer greater thermal stresses in winter compared with adults because the ratio of surface area to volume (SA : vol) is much greater for calves than for adults. We found that during feeding bouts, when animals are fully exposed to environmental conditions, calves did lose sensible (dry) heat more readily than adults (W m(-2)) in still air conditions. However, calves and cows lost less than 2%-6% of their estimated daily digestible energy intake as conductive, convective, and radiant heat losses accumulated during feeding bouts. More important, calves did not lose relatively more heat than larger adults in terms of sensible losses as part of their daily energy intake. Coat surface temperatures were only 2 degrees-5 degrees C above ambient even when air temperature fell to -40 degrees C. Body temperatures recorded deep within the ear canal near the tympanum fluctuated in both cows and calves. Muskoxen combine peripheral heterothermy and an exceptional winter coat to minimize sensible heat loss in winter. These mechanisms appear to have circumvented some of the thermal problems normally associated with a high SA : vol ratio in calves, which reflects the strong selection to conserve energy in winter. ABSTRACT Muskoxen (Ovibos moschatus) are large (1200 kg adult body mass) mammalian herbivores that overwinter in the polar regions. Calves are around one-third the body mass of mature females and may be expected to suffer greater thermal stresses in winter compared with adults because the ratio of surface area to volume (SA : vol) is much greater for calves than for adults. We found that during feeding bouts, when animals are fully exposed to environmental conditions, calves did lose sensible (dry) heat more readily than adults (W m Ϫ2 ) in still air conditions. However, calves and cows lost less than 2%-6% of their estimated daily digestible energy intake as conductive, convective, and radiant heat losses accumulated during feeding bouts. More important, calves did not lose relatively more heat than larger adults in terms of sensible losses as part of their daily energy intake. Coat surface temperatures were only 2Њ-5ЊC above ambient even when air temperature fell to Ϫ40ЊC. Body temperatures recorded deep within the ear canal near the tympanum fluctuated in both cows and calves. Muskoxen combine peripheral heterothermy and an exceptional winter coat to minimize sensible heat loss in winter. These mechanisms appear to have circumvented some of the the...

show abstract

Growth in an Arctic Grazer: Effects of Sex and Dietary Nitrogen on Yearling Muskoxen

Cited by 23 publications

References 73 publications

Differential resource allocation strategies in juvenile elephant seals in the highly seasonal Southern Ocean

Differential resource allocation strategies in juvenile elephant seals in the highly seasonal Southern Ocean

Defining the predator landscape of northeastern British Columbia.

Sensible Heat Loss from Muskoxen (Ovibos moschatus) Feeding in Winter: Small Calves Are Not at a Thermal Disadvantage Compared with Adult Cows

Contact Info

Product

Resources

About