Beginning with Emlen (1966) and MacArthur and Pianka (1966) and extending through the last ten years, several authors have sought to predict the foraging behavior of animals by means of mathematical models. These models are very similar,in that they all assume that the fitness of a foraging animal is a function of the efficiency of foraging measured in terms of some "currency" (Schoener, 1971) -usually energy- and that natural selection has resulted in animals that forage so as to maximize this fitness. As a result of these similarities, the models have become known as "optimal foraging models"; and the theory that embodies them, "optimal foraging theory." The situations to which optimal foraging theory has been applied, with the exception of a few recent studies, can be divided into the following four categories: (1) choice by an animal of which food types to eat (i.e., optimal diet); (2) choice of which patch type to feed in (i.e., optimal patch choice); (3) optimal allocation of time to different patches; and (4) optimal patterns and speed of movements. In this review we discuss each of these categories separately, dealing with both the theoretical developments and the data that permit tests of the predictions. The review is selective in the sense that we emphasize studies that either develop testable predictions or that attempt to test predictions in a precise quantitative manner. We also discuss what we see to be some of the future developments in the area of optimal foraging theory and how this theory can be related to other areas of biology. Our general conclusion is that the simple models so far formulated are supported are supported reasonably well by available data and that we are optimistic about the value both now and in the future of optimal foraging theory. We argue, however, that these simple models will requre much modification, espicially to deal with situations that either cannot easily be put into one or another of the above four categories or entail currencies more complicated that just energy.

Citation classic - optimal foraging - a selective review of theory and tests

Nutrient requirements of dairy cattle , Nutrient requirements of dairy cattle , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Nutrient requirements of dairy cattle

ION, GENERAL CONCEPTIONS, SELF-CONSCIOUSNESS, MENTAL INDIVIDUALITY. It would be very difficult for any one with even much more knowledge than I possess, to determine how far animals exhibit any traces of these high mental powers. This difficulty arises from the impossibility of judging what passes through the mind of an animal; and again, the fact that writers differ to a great extent in the meaning which they attribute to the above terms, causes a further difficulty. If one may judge from various articles which have been published lately, the greatest stress seems to be laid on the supposed entire absence in animals of the power of abstraction, or of forming general concepts. But when a dog sees another dog at a distance, it is often clear that he perceives that it is a dog in the abstract; for when he gets nearer his whole manner suddenly changes, if the other dog be a friend. A recent writer remarks, that in all such cases it is a pure assumption to assert that the mental act is not essentially of the same nature in the animal as in man. If either refers what he perceives with his senses to a mental concept, then so do both. (44. Mr. Hookham, in a letter to Prof. Max Muller, in the 'Birmingham News,' May, 1873.) When I say to my terrier, in an eager voice (and I have made the trial many times), "Hi, hi, where is it?" she at once takes it as a sign that something is to be hunted, and generally first looks quickly all around, and then rushes into the nearest thicket, to scent for any game, but finding nothing, she looks up into any neighbouring tree for a squirrel. Now do not these actions clearly shew that she had in her mind a general idea or concept that some animal is to be discovered and hunted? It may be freely admitted that no animal is self-conscious, if by this term it is implied, that he reflects on such points, as whence he comes or whither he will go, or what is life and death, and so forth. But how can we feel sure that an old dog with an excellent memory and some power of imagination, as shewn by his dreams, never reflects on his past pleasures or pains in the chase? And this would be a form of self-consciousness. On the other hand, as Buchner (45. 'Conferences sur la Theorie Darwinienne,' French translat. 1869, p. 132.) has remarked, how little can the hardworked wife of a degraded Australian savage, who uses very few abstract words, and cannot count above four, exert her self-consciousness, or reflect on the nature of her own existence. It is generally admitted, that the higher animals possess memory, attention, association, and even some imagination and reason. If these powers, which differ much in different animals, are capable of improvement, there seems no great improbability in more complex faculties, such as the higher forms of abstraction, and selfconsciousness, etc., having been evolved through the development and combination of the simpler ones. It has been urged against the views here maintained that it is impossible to say at what point in the ascending scale animals become capable of abstraction, etc.; but who can say at what age this occurs in our young children? We see at least that such powers

https://www.jstage.jst.go.jp/article/ase1887/22/257/22_257_458/_pdf

The descent of man and selection in relation to sex

What makes a face attractive and why do we have the preferences we do? Emergence of preferences early in development and cross-cultural agreement on attractiveness challenge a long-held view that our preferences reflect arbitrary standards of beauty set by cultures. Averageness, symmetry, and sexual dimorphism are good candidates for biologically based standards of beauty. A critical review and meta-analyses indicate that all three are attractive in both male and female faces and across cultures. Theorists have proposed that face preferences may be adaptations for mate choice because attractive traits signal important aspects of mate quality, such as health. Others have argued that they may simply be by-products of the way brains process information. Although often presented as alternatives, I argue that both kinds of selection pressures may have shaped our perceptions of facial beauty.

/pdf/the-evolutionary-psychology-of-facial-beauty-2ztdp2t50v.pdf

The evolutionary psychology of facial beauty.

Why do females prefer elaborate male mating displays in species where they receive little more from males than their sperm? Here we review three hypotheses for the evolution of mating preferences: direct selection, the runaway process and the parasite mechanism. There is growing support for direct selection, in which preferences evolve because of their direct effects on female fitness rather than the genetic effects on offspring resulting from mate choice.

The evolution of mating preferences and the paradox of the lek

Identifying pain in farm animals.

Modern freestall barns for dairy cattle have been constructed with considerations for dairy cow cleanliness; partitions and other stall features such as neck rails are designed to reduce manure contamination of bedding and decrease farm labor. However, cows prefer to lie in more open spaces, including on bedded packs and pasture. We created an "alternative" housing area by modifying a traditional freestall pen and including flexible partitions to create larger lying areas. We assessed cattle lying behaviour, including lying postures, in this alternative pen (ALT) compared to an open pack (OP) and freestalls (FS) with different stocking densities. We also assessed levels of manure contamination across systems. Cleanliness was highest in FS, but ALT provided substantial improvement compared to OP. Cattle spent more time lying down in OP and ALT compared to FS. There were few differences in postures (such as lying with limbs outstretched) between OP and ALT, but cows in both of these systems more often lay in extended positions compared to when they were housed in FS. Housing in OP and ALT was associated with reduced perching for cows with high body weight; perching has been linked to an increased prevalence of both hoof lesions and lameness. Thus, alternative lying areas can offer a solution for producers seeking to provide cattle with the advantages of a more open lying area, while improving hygiene relative to an open pack.

https://www.mdpi.com/2076-2615/11/6/1711/pdf

The Freestall Reimagined: Effects on Stall Hygiene and Space Usage in Dairy Cattle.

Changes in feeding and standing behavior of transition cows predict risk of sole hemorrhages and ulcers

Animal welfare is emerging as one of the key social concerns regarding animal agriculture. Concern for the welfare of farms animals is not new, but the last few years have seen increased interest in farm practices. One of the dairy industry's core strengths is the very positive view that many people have about dairy farming. Many consumers believe that cows spend their days grazing green pastures. This strength can also be regarded as a threat if some industry practices no longer match evolving public expectations. Every year there are fewer farms, and the ever decreasing proportion of society that works within this industry will never be able to able to 'educate' the large majority, at least not on all issues, all of the time. Moreover, the farmers themselves are part of this rapidly evolving society, and practices that were accepted by past generations as necessary may not seem so to the next generation of producers. Change will happen. During my presentation I will highlight some of our most recent work on engaging dairy farmers and the public as a means to help identify practices that do and do not come into harmony with public expectations.

Stakeholder views, including the public, on expectations for dairy cattle welfare

Since 1985, China has been the world’s largest egg producer. In 2020, 3.3 billion layer hens were reared in China, producing 29.8 million tons of eggs (around 40% of the world’s egg production, see Figure 1; FAO, 2022). Battery cage production became common in China in the 1980s and by 2017 approximately 90% of farms used cages (IEC, 2017). Internationally, concern for animal welfare has begun to encourage a shift towards less confined housing systems, including cage-free housing for hens (with or without access to the outdoors). Any transition to cage-free systems will depend upon a variety of factors including the values of consumers and the way these eggs are marketed. The effects of this transition on hen welfare will depend on the degree to which cagefree housing methods actually benefit the birds themselves. In this paper we review the development of cage-free farming in China in relation to consumer preferences and hen welfare. Our aims are to 1) describe the history of egg production in China, including changes in cage-free production, 2) describe current consumer preferences for eggs, including attributes associated with hen housing and welfare, 3) review the link between cage-free housing and hen welfare, 4) describe approaches to help improve hen welfare on cage-free farms, and 5) identify areas for future research.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9947321

Daniel M. Weary

Papers

Identifying pain in farm animals.

The Freestall Reimagined: Effects on Stall Hygiene and Space Usage in Dairy Cattle.

Changes in feeding and standing behavior of transition cows predict risk of sole hemorrhages and ulcers

Stakeholder views, including the public, on expectations for dairy cattle welfare

Cage-free eggs in China