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

A common feeding practice during the dry period is to switch dairy cows to an energy-dense diet 3 wk prepartum, but this practice may lead to the overconsumption of energy and increase the risk of metabolic disease postpartum. The aim of this trial was to compare the metabolic status of transition Holstein dairy cows fed a 77% forage diet (77F; NEl = 1.46 Mcal/kg; NDF = 41%) vs. those fed an 87% forage diet (87F; NEl = 1.41 Mcal/kg; 48% NDF). Approximately 60 d before calving, cows were dried off, housed in a free stall barn, and fed the 87F diet. Three weeks before expected calving, cows were randomly assigned to either the 77F treatment and switched to this diet (n = 45) or assigned to the 87F treatment and stayed on the dry cow ration until parturition (n = 42). After parturition, all cows were fed a common lactation diet (NEl = 1.59 Mcal/kg; 36% NDF). Dry matter intake was measured daily from 2 wk before to 2 wk after calving. Blood was sampled daily for 10 d postpartum. Subclinical ketosis was diagnosed using a threshold of β-hydroxybutyrate (BHBA) ≥ 1.0 mmol/L after calving. The percentage of cows pregnant and odds of being pregnant for each treatment group were determined at 60, 90, and 120 d in milk through ultrasound by the herd veterinarian. Cows on the 87F diet consumed less DM prepartum than those on the 77F diet (12.7 ± 0.3 kg/d vs. 15.4 ± 0.3 kg/d, P < 0.001), but no difference in DMI was detected after calving (19.7 ± 5.5 kg/d; P = 0.87). Although the calculated prepartum required energy intake was the same for the 2 treatments (15.3 ± 1.2 Mcal/d; P = 0.16), cows on the 77F diet consumed 4.5 Mcal/d more than those on the 87F diet (22.5 ± 0.5 Mcal/d vs. 18.0 ± 0.5 Mcal/d; P < 0.001). Postpartum concentration of BHBA was less for cows fed the 87F diet prepartum (0.49 ± 0.02 mmol/L vs. 0.59 ± 0.02 mmol/L; P = 0.02), and fewer animals on this diet were diagnosed subclinical ketosis (SCK; 49% vs. 17%; P = 0.001). Milk production tended to be less for cows fed the 87F diet prepartum (47.3 ± 0.4 kg/d vs. 48.8 ± 0.4 kg/d; P = 0.10) for the first 22 wk of lactation, which was significant for d 7 to 28 of lactation (44.6 ± 1.1 kg/d vs. 47.6 ± 1.0 kg/d; P = 0.05). Although sample size was small to draw strong conclusions on reproductive performance, at 120 d in milk, cows on the 87F diet were 0.3 times more likely to be pregnant (P = 0.03). These results indicate that feeding an 87F diet before calving can reduce rates of SCK in transition dairy cows.

Feeding a higher forage diet prepartum decreases incidences of subclinical ketosis in transition dairy cows

A. L. Basolo teStS the: hypothesis that, in the: swordless platytish. Xiphophonts rruu:ul4rus, female: mate choice: arises from a prc:c:xisting sensory bias (1). Basolo shows thar ti:males c::xhibir a mating pn:fi::rc:nce for males with an at:C1chc::d, arrificia.!, colored sword whc:n given a choice: bc:rwo:n thc:sc: males and males with an arrificia.!,rransparc:nr sword as a controL Because: swordlessness is the: ancc:srral sran: of the:Xiphophorus clade:, Basolo argues thar the: results of her c:xpc:rimc:nrindican: rh.ar fanale: pn:fc:rc:nce: for swords predateS the: evolurion of the: sword and concludes thar coc:volutionary modds of sc::x112l sc:lc:aion arc: inadequarc:. Basolo provides no d.irca evidence in supporr of a prc:cxi.sringfc:male:sc:nsorybias, bur rejc:a:s the: coc:volutionary hypothc:sc:s of mare-choice: evolution. Fc:male: platyfish may have: ahibited a preference: for artificially sworded males be:Cluse: thc:sc:males wc:rc:novcl (2). The: approprian: control for t:his possibility would be: males with some: other shapes aa:u:hed rhar do nor n:sc:mble:any marking on males, a blue:rriangie:, for c::x:ample:. If fc:maJ.esprefer males with a triangle: co those: withoUt, then ti:males arc:clc::arlyamaca:d ro novcl males. If t:hisresr shows that fi:malc:sarc:nor aancred co novcl males, then ir would be:nc:a:ssary co demonstran: rh.ar fc:m.alesarc:ac:raacd ro the: sword per sc: and nor the: com:cxt in which the: sword is displayai This is an importanr distinction, beaus rhing a sword co areas other than the: lower edge of the:Cludal fin. The: mOStconvincing supporr for the:sensory-bias hypothesis would come: from a dc:monsrr:u:ionthatmalc:sshow a mating ?,cf...u;ua: for fc:males bearing swords. This counrc:rinruirivc: prediction daM:s from the: hypothesis rhar a female:sc:osorybias c:volvc:s in response: co some: c:nvironmc:nal stimulus. Basolo gives the: c::x:ample: that fc:maJ.c:s may have: c:volved a search image for a favorite food and thc:n prcfc:m:d co mate with males that sporrc:d an appc:ndage resembling this food. In such a scc:nario, malc:swould be:just as liIa:1yco c:volve:the: sensory bias, as they arc: also subjc:a to sc:lc:crionto dca:cr food. The: prediaion rh.ar males pn:fc:r fc:males with swords should be:tested with a swordk:ss species whose: fc:malc:sahibit a sword ptd\:...<.ucc:, as the: swords of sworded speci~ 1~ may be: usc:d by males as an indiClror of gc:nder (3). Even if males prefc:rrc:dfanales with swords, fanale: swords would not be: e:xpc:aed to have: c:volved.,as sworded females arc: not likc:lyto have: c:xpc:riencc:da mating advanc.gc:. This is beaus<: fc:maJ.e: gc:st:1tionin thc:sc:live:-bearing spc:ciesprobably mc:ansthat females arc: the: limiting sex.. Is the: sc:nsory-bias hypothesis tenable:: One: must ask why a female:might want to mate with a male: associated with some:thing that looks good to eat. It cannOt be: argued that males with swords arc: more: easily de:tc:Cte:dby fe:malesbeause: of limitS to female: visual perce:ption; X mtU:ulatus males and males of the: sworded species X hd1eri both perform complex courrship displays at very close: range: to fc:m.ales(3, 4). Pe:rhaps some: constraint on the: dc:vclopmc:nt of nc:ural circuitry causes fc:males ro court attractive: obje:CtSeven though they provide: no information about mate: type:or quality. As pointed our by Basolo, this is nor the:same:as a novcl-male: dfc:ct, as such a hypothesis doc:s not c:xplain the: wtion of sword gc:nes in a population. Nc:vc:rthe:less, narural sc:lc:crionwould likely favor a srrarcgy of informc:d mate choice: over arbitrary mate choia:. FUrther testS of the: sensory-bias hypothesis would be: usc:ful., but the:premise: of the:hypothesis must first: be:carc:fullyexamined. JACK DA Sn..VA DqxutmDIl of Biology, McGi1I Univcsity, M~ QudJ«, H3A 1B1, Canada

Male swords and female preferences.

Personality is associated with feeding behavior and performance in dairy calves

Short communication: effects of bedding quality on the lying behavior of dairy calves.

In natural environments, cattle use trees and other abrasive surfaces to scratch and groom themselves. Modern indoor dairy cattle housing systems often lack appropriate grooming substrates, restric...

https://royalsocietypublishing.org/doi/pdf/10.1098/rsbl.2018.0303

Daniel M. Weary

Papers

Feeding a higher forage diet prepartum decreases incidences of subclinical ketosis in transition dairy cows

Male swords and female preferences.

Personality is associated with feeding behavior and performance in dairy calves

Short communication: effects of bedding quality on the lying behavior of dairy calves.

Cows are highly motivated to access a grooming substrate