Biomedical subjects
P H Brooks
Publications and source records attributed to P H Brooks.
Supplementary biotin for sows: effect on claw integrity.
Eighty female pigs were fed, from 25 kg liveweight, either basal diets calculated to provide 32 micrograms available biotin/kg (control diet) or basal diets supplemented with 350 micrograms biotin/kg. Their claws were examined and lesions recorded at 170 days of age and when each of their first four litters was weaned. The incidence of horn 'defects' (superficial bruises, abrasions and cuts in the soft heel) remained at a low level throughout the trial. Neither the number of claws affected with lesions nor the number of lesions per sow differed between treatments at 170 days of age. Between 170 days of age and first weaning the incidence of hoof lesions increased greatly. At first weaning and for the remainder of the trial biotin supplemented sows had significantly fewer claw lesions per sow than controls (P less than 0.05 or greater). The predominant injuries to the foot were cracks which occurred mainly in two associated regions, the heel/toe junction and the heel, and the sidewall and adjacent white-line region of the toe. The differences in foot damage did not result in differences in culling rate. It was concluded that supplemention of the diet of breeding sows with biotin from an early stage of development made a significant contribution to the maintenance of their horn integrity.
Water intake of weaned piglets from three to seven weeks old.
One hundred and two large white cross landrace piglets weaned at 21 (+/- 1) days old were randomly allocated to one of two commercial early weaning diets for a four week growth trial. The piglets were housed in groups of between six and 10. After initial moderate restriction the piglets were fed ad libitum. Food intakes and weight gains were recorded weekly. Water consumption of individual pens of piglets was recorded daily. Dietary treatment had no significant effect on mean daily feed intake, daily liveweight gain or food conversion ratio. The relationship between water and food intake, piglet weight and daily gain was examined using regression and multiple regression analyses. Water intake was related to all these parameters, with daily feed intake being the best single predictor of water intake. The relationship was described by the equation: water intake (litres/day) = 0.149 + 3.053 feed intake (kg/day).
Cognitive research in mental retardation.
Virtually all investigators currently conducting cognitive research in mental retardation address directly or indirectly the question of cognitive modifiability. Within that context we have dichotomized the research for discussion purposes into two classes. The first class includes research aimed at the development of an empirically based cognitive model of mental retardation. Investigators who do this work believe that strategies for cognitive modifiability will follow directly from a thorough understanding of the structures and processes that comprise the cognitive system. The second class of cognitive research in mental retardation is composed of studies on intervention. This research is focused on identification of cognitive deficiencies and subsequent attempts to alleviate these deficiencies. In this paper we have briefly provided examples of research from both classes chosen from ongoing research at the John F. Kennedy Center for Research on Education and Human Development.
Supplementary biotin for sows: effect on reproductive characteristics.
Eighty female pigs were fed from 25 kg liveweight either basal diets calculated to provide 32 micrograms available biotin/kg (control diet) or basal diets supplemented with 350 micrograms biotin/kg. Reproductive performance was studied over four parities. Sows receiving supplementary biotin returned to oestrus 2.9 +/- 1.7 and conceived 6.1 +/- 1.4 days sooner than controls (P less than 0.05). Of those sows receiving supplementary biotin, more returned to oestrus and conceived within 10 days of weaning (83.2 per cent v 74.6 per cent and 80.6 per cent v 71.8 per cent respectively) and fewer were treated for anoestrus (7.3 per cent v 17.0 per cent) than those on the control diet. Supplementing diets increased the annual productivity of sows completing four parities by 1.42 +/- 1.02 pigs/sow/year (P less than 0.05) and increased the total weight of weaner produced/sow/year by 17.3 +/- 7.4 kg (P less than 0.05). It was concluded that the majority of commercial dietary formulations would require supplementation with biotin in order that sows may express their full reproductive potential.
Treatment of anoestrus in the pig.
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Monochorionic "twins" in multiparous sows.
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Biotin-supplementation of diets; the incidence of foot lesions, and the reproductive performance of sows.
The effect of biotin supplementation of diets for breeding sows was investigated in a herd where the sows exhibited symptoms resembling those of experimentally induced biotin deficiency. Twenty sows received diets supplemented with 250 mcg D-biotin per kg in pregnancy and 150 mcg D-biotin per kg in lactation. Over a six month period the supplemented sows showed a 28 per cent reduction in the number of foot lesions recorded. Twenty-two control sows showed no reduction in foot lesions. Sows on the supplemented diets produced more piglets at birth than controls, but the differences were not significant. However, second parity supplemented sows did produce significantly more live pigs than controls (1-64 +/- 0-77, P less than 0-05). The weaning to remating interval was significantly reduced from 15-31 +/- 2-85 days in the controls to 6-23 +/- 2-85 days in the supplemented sows (P less than 0-05) and the percentage of sows exhibiting oestrus within seven days of weaning was increased from 56 per cent to 89 per cent.
A plea for consideration of ecological validity in the experimental psychology of mental retardation: a guest editorial.
The point was raised that, despite considerable experimental effort, laboratory research concerning learning, memory, and cognition, more generally, has not produced a very remarkable increase in our understanding of retarded behavior. Our principal contention in this paper is that the experimental psychology of mental retardation, while basically seeking causal relations between theoretical constructs and retarded behavior, is suffering from some metatheoretical and methodological shortcomings. These include, basically, a prevalent failure to consider the ecological aspects of the phenomenon of mental retardation. Implications of ecological validity are important with respect to the basis upon which subjects are selected for experimentation, the rationale underlying manipulation of independent variables, the choice of dependent variables, and the definition of the boundaries that limit generalizations. Some suggestions were offered for the purpose of guiding experimental research toward more meaningful and socially relevant goals.
Are we making a science of missing the point?
Our basic point of contention with House concerns the form we ultimately expect our sceintific explanations of retarded behavior to take. It is our view that mental retardation, which is basically a social phenomenon, can be meaningfully understood only to the extent that ecological validity and other related issues are assigned prominence in our theories and experiments.
The effect of feed pattern in lactation and fasting following weaning on reproductive phenomena in the sow.
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The effect of feed level during the oestrous cycle on ovulation, embryo survival and anterior pituitary LH potency in the gilt.
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Lactational anoestrus in the sow.
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The effect of feed level during oestrus on ovulation rate in the gilt.
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The effect of the presence of a boar on the attainment of puberty in gilts.
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