The maternal environment exerts important influences on offspring mass/growth, metabolism, reproduction, neurobiology, immune function, and behavior among birds, insects, reptiles, fish, and mammals. For mammals, mother's milk is an important physiological pathway for nutrient transfer and glucocorticoid signaling that potentially influences offspring growth and behavioral phenotype. Glucocorticoids in mother's milk have been associated with offspring behavioral phenotype in several mammals, but studies have been handicapped by not simultaneously evaluating milk energy density and yield. This is problematic as milk glucocorticoids and nutrients likely have simultaneous effects on offspring phenotype. We investigated mother's milk and infant temperament and growth in a cohort of rhesus macaque (Macaca mulatta) mother-infant dyads at the California National Primate Research Center (N = 108). Glucocorticoids in mother's milk, independent of available milk energy, predicted a more Nervous, less Confident temperament in both sons and daughters. We additionally found sex differences in the windows of sensitivity and the magnitude of sensitivity to maternal-origin glucocorticoids. Lower parity mothers produced milk with higher cortisol concentrations. Lastly, higher cortisol concentrations in milk were associated with greater infant weight gain across time. Taken together, these results suggest that mothers with fewer somatic resources, even in captivity, may be "programming" through cortisol signaling, behaviorally cautious offspring that prioritize growth. Glucocorticoids ingested through milk may importantly contribute to the assimilation of available milk energy, development of temperament, and orchestrate, in part, the allocation of maternal milk energy between growth and behavioral phenotype.

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Cortisol in mother’s milk across lactation reflects maternal life history and predicts infant temperament

Cook, N. J. 2012. Review: Minimally invasive sampling media and the measurement of corticosteroids as biomarkers of stress in animals. Can. J. Anim. Sci. 92: 227–259. The measurement of corticoster...

https://bioone.org/journals/Canadian-Journal-of-Animal-Science/volume-92/issue-3/CJAS2012-045/Review--Minimally-invasive-sampling-media-and-the-measurement-of/10.1139/CJAS2012-045.pdf

Review: Minimally invasive sampling media and the measurement of corticosteroids as biomarkers of stress in animals

Adaptation by learning: its significance for farm animal husbandry

Long-term physiological stress in individual animals may be an important mechanism linking ecological change with impaired wildlife population health. In the Southern Hudson Bay (SH) subpopulation of polar bears (Ursus maritimus), increasing stress associated with climate warming may be related to declining body condition. Accordingly, the development of tools to assess long-term stress in this species may prove invaluable for conservation efforts in this threatened population. The measurement of hair cortisol concentration (HCC) has shown promise as a potential biomarker of long-term stress in free-ranging bears. However, to serve as a useful management tool, factors influencing HCC in polar bears must be identified and then revealed to establish linkages between environmental conditions and the fitness of individual animals. We determined HCC (median = 0.48 pg/mg [range = 0.16–2.26 pg/mg]) in 185 polar bears captured in southern Hudson Bay from 2007 to 2009. HCC was influenced by sex, family group status, and capture period but not by body region or hair type. Using models developed through a combination of hypothesis testing and information theory, we also determined that HCC was negatively associated with growth indices (length, mass, and body condition index) linked to fitness in polar bears. Additional research will be required across several polar bear populations to establish the utility of HCC as a tool for polar bear conservation. © 2012 The Wildlife Society.

Evaluation of hair cortisol concentration as a biomarker of long‐term stress in free‐ranging polar bears

Different tests have been developed for evaluating the temperament of cattle, pigs, and sheep and some studies appear to have conflicting results. This may be due to confusion between the basic emotional systems of fear and separation distress (panic). Methods used for temperament tests can alter results such as how tightly an animal is restrained in a squeeze chute during temperament evaluation. Animals with a more reactive (fearful) temperament will exhibit greater agitated behavioral reactions when suddenly confronted with novel objects. Animals can be habituated to new things but learning is very specific. Habituation to one type of strange object may not transfer to other types of objects. Animals with smaller-diameter leg bones and slender bodies may be more reactive (fearful). Facial hair whorl position is related to a vigilant temperament and it may be more evident in populations with more diverse genetic backgrounds.

Genetics and behavior during handling, restraint, and herding.

Effect of lactation stage, season and parity on milk cortisol concentration in Holstein cows

We examined the role of trees as grooming objects in grazing pasture and investigated their necessity. Four grazing Japanese Black cows were used. Experimental pastures with restricted (RST) and released (RLS) grooming with trees were established. Examination was carried out for 24 h in each RST and RLS. The respective frequencies and duration of self-grooming, allo-grooming (social grooming) and grooming with trees was recorded by a continuous scan sampling method, and maintenance behavior was recorded by a 2-min group animal scan sampling method. Grooming with trees in RLS occurred 29 ± 12 times/24 h and for 1342 ± 475 s/24 h. Total frequencies and duration of grooming in RLS tended to increase from that in RST (P = 0.08, P = 0.06, respectively). However, self-grooming and allo-grooming exhibited no differences. The results indicate that cattle may enrich their grooming through the use of trees if the latter are available. Furthermore, they may not substitute grooming with trees with other forms of grooming if no trees are available in the grassland. No difference was observed in the general proportion of their maintenance behavior. These results suggest that trees in grassland provide a good environmental enrichment object that satisfies cattle's potential needs of grooming and did not restrict their general behavior.

Effect of environmental enrichment by providing trees as rubbing objects in grassland: Grazing cattle need tree‐grooming

The objective of this study was to examine the relationship between milk cortisol concentration (MC) and behavioral responses to stress. As a stress response, the behaviors of 37 postpartum cows were observed when they were introduced into a new group. Milk samples for MC measurement and milk trait data were collected on the test day every 2 months after calving. The best linear unbiased prediction (BLUP) was estimated from each behavioral and milk trait data. Behavioral BLUP data were subjected to principal component (PC) analysis and three PCs were extracted. The first PC, with large loadings for eating and allogrooming, was positively correlated with milk yield. Therefore, individual differences in behaviors closely related with PC1 would have been unconsciously paid a lot of attention in terms of productivity. However, the second PC, with large loadings for drinking and self-grooming, uncorrelated with any milk traits, had a negative correlation with MC. The third PC, with large loadings for exploring, fighting and the frequency of agonistic behavior, was uncorrelated with all traits. Both PC2 and PC3 were independent of productivity, and individual differences in behaviors related with these PCs may be scarcely considered.

Michiru Fukasawa

Papers

Effect of lactation stage, season and parity on milk cortisol concentration in Holstein cows

Effect of environmental enrichment by providing trees as rubbing objects in grassland: Grazing cattle need tree‐grooming

Relationship between milk cortisol concentration and the behavioral characteristics of postpartum cows introduced to a new group

Ensiling and subsequent ruminal degradation characteristics of barley tea grounds treated with contrasting additives

Welfare of lactating Holstein cows under outdoor grazing and indoor housing in relation to temperature and humidity in summer in Japan