7707

• UCREFRP Catalog Number: 7707
• Author: Saul, G. E.
• Title: Effects of repetitive electroshocking on fish populations in experimental raceways and a small headwater stream in southern West Virginia
• USFW Year: 1981
• USFW - Doc Type: 41‎(12)‎
• Copyright Material: YES

.. 4320-B,

q~l

AGRICULTURE, Al\1MAL CULTURE Al\U ~'UfRITION

() '17tJ

ASSOClA nON OF GROWfH AND ENDOCRINE FUNCIlON IN
TIIE PREPUBERTAL BEEF CALF: L AGE AND SEX
DIFFEREJ\crs IN PITUITARY RESPONSIVEl\'F.SS TO GNRH.
n. AGE AND SEASON DIFFERENCES IN NEGATIVE
FEEDBACK MECH.AI\1SMS REGULATING lJJ SECJU:llON.
In. RELA TIONSHlP OF GROWTH AND PUBERTY IN BEEF
HEIFERS FED MO!\'ENSIN Order No. 8111610
MOSElJn', WIlJ..LUf MICHAEL.. PH.D. University qfWyoming,1980. UOpp.
Two uperiment$ were COI1l1\1cte4 \0 c1etennint lie and sex cWrerlUlccs :
Dirsenation Abstracts InterTUltionaJ Vol ~1 No. J] JU1l8 1981

same foundation stock.. Suain 5 is a randombred control and Strain 3 bad
been selected for early-year egg production in intenningled-straiD floor
pens for 15 years and subsequently in single-bird cages for five years. Three
laying-house environments involved in Experiment 1 were: single-bird
cages, separated-strain floor pens. and intermingled-strain floor pens. In
addition. Experiment 2 also included a thr~bird cage environment There
were 360 and 384 pullets per strain involved in Experiments 1 and 2.
respea.ively.
In order to measure the social status of pullets within flocks, a social
rank index (X) was devised. It is defineel as: X = Ih(D - S + N + 1). where
D = number dominated. S = number dominating. and N = group size.
Behavioral data obtained from eight separated-strain fiocks in Experiment 2
were analyzed to stuely the properties of the social rank index anel its
relationships with other measures of agonistic behavior and.with
productivity traits.
Social rank index appeared to be a better measurement of individual
social statuS than social tension index (total aggressive acts min.us total
submissive acts), because it tended to be more normally distributed..
Regression of the frequency of agonistic behaviors on social rank indei
indicat.ed that most agonistic interactions occurring in the flock were
associated with pullets near the top of the peck order delivering aggressive
acts towarel those near the bottom of the peck order.
Comparisons of the linear and three curvilinear regression moc1els
indicated a definite tendency toward curvilinear relationships between an
individual's social statUS and its productivity within the flock.. The egg
proc1uction of pullets at or near the bottom of the peck order was
disproportionately depressed.
Both experiments indicated that pullets of selected Suain 3 had social
dominance over control Suain 5 pullets when five months olel (before
sexual mawrity). but domin:mte by Suain 3 females diminished or
disappeared when strangers of the two strains were placed together when
17 months old. Nevertheless, because ofsocial inertia, Strain 3 pullets
maintained undiminished dominance over Strain 5 pullets for the entire
laying year when individuals were kept together from housing time onward.
Suain 3 pullets had more aggressive acts. more feeding activity. and
spent less time resting than did Strain 5 pullets in both separated- and
intenningled-strain housing environments. When pullets of the two strains
were kept together. the relative frequencies of their agonistic behaviors
were dwlged, but nonagonistic activities were not altered.
Genotype by environment interactions were detected as being
significant in Experiment 1 for egg and body weights, and in Experiment 2
for rate of lay. livability, egg weight, hen-housed rate of lay, egg mass, body
weight, and body weight gain. Although fewer genotype by en\ironment
interactions were found in Experiment 1. there was a distinct tendency for
the suains to differ (or fail to differ) in similar ways in each of the three
environments compared in the two experiments.
Pullets of the more aggressive anel socially dominant selected Strain 3
were generally superior in performance to unselected Strain 5 pullets when
they were intermingled in floor pens, but those differences tended to
disappear when pullets of the two strains were kept in separated-strain
fiocks. These results are taken as indirect evidence supporting the
conclusion that differences in stress associated with the social environment
may contribute to genotype by housing environment interactions for
performance traits.
linear and curvilinear regression analyses for pullets in single-bird
cages indicated that selected Suain 3 indivieluals were. on the average. near
their optimal body weights, but unselected control Suain 5 pullets were
overweight under conditions of unlimited feed availability.

I!\'FLUENCE OF DIETARY MODIFICATIONS ON TIlE
INCIDE.~CE OF FATrY UVER HEMORRHAGIC SYNDROME IN
JAPANESE QUAIL A.l\'D LAYING HENS Order No. 8108828
M.+. TOO. D.1l.MENcrr A DIR.ECTO, PH.D. University of M WoUn - Columbia.
1980. 192pp.
Abstract Not Available.

in the feedback mech~ni"'".S regulating luteinizing hormone secrelion of the .
prepubertal calf. Another experiment was designed to determine whether
feeding monensin had an effect on age and weight at puberty which is
inelependent of increased body weight gains.
Age and sex differences in pituitaIy responsiveness of prepubertal beef
calves to gonadotropin releasing hormone (GnRH) were determined in the
.first study. A single injection of 125 p.g GnRH induced a sigr>ificantrise in
serum luteinizing hormone (UI) concentrations in fall and SPrin& born
heifers at 60 and 200 days of age and in fall bom bulls at 100 and 200 days
of age. The magnitude of the Ul peak. duration of the Ul peak and.area of
Ul response curve was similar between ages and season ofbinh in heifers.
D.uation of the ill peak and area of ill response curve were grea1er in
lQO-day-old bulls than 200-day-old bulls and heifers at bothaaes. The
magnitude of the ill peak was greater in bulls than heifers..
A second study was designed to examine the effectSo( age and sea50lI of
birth on the response of the hypothalamic:-pituitaIy-gonadalaxis 10. the
negative feedback. action of estradiol in the prepubertal beefhei(er. Fall
and spring born heifers, 60 and 200 days of age, were assigned 10 on&: of
three treatment groups: (1) control-intact; (2) ovariectomy; or. ....
(3) ovariectomy plus estradiol-17fJ <EU arlmini~('led in si1astic implants.
ill was measured in serum samples collected at 2O-min intervals for 4
hours the day before and 7. 2l. 35 and.49 days after ovarieaomy. Removal
of the ovaries resulted in elevated serum UI concentrations at both 60 and
200 days of age. A transition was made from basal Ul with a low ~uency
of pulsatile LH secretion prior to ovariectOmy to a panero characterized by
rllythmic LH pulses at hourlyinteIVals by .49 days after ovariecUmy. The
inhibition of the post-ovariectomy rise in serum ill by E2 replacement
therapy demonstrateS that ~ exerts negative feedback on pituiwy UI
secretion in the prepubertal beef heifer. Mean serum E2 concentrations
were three times greater than oontrol or ovariectomized heifers but the
latter were similar. Seasonal variation in the negative feedback action of~
on ill secretion may exist in 200-day-old but not in 6O-day-oldheifers. ...
In the final experiment one hundred forty crossbred beefheifers were
allotted to either a heavy (H) or light (L) group consisting of heifers with .
above and below the average weaning weights, respectively. Within weight
class, heifers were assigned to receive one of three feed treatments for 2D3
days: (1) roughage diet (R) fed SO% roughage and 20% concentrate; (2) R
plus monensin (Ml) fed to proc1uce same daily gains as R by reducing feed
intake 10%; (3) R plus monensin (M2) fed the same daily feed intake as R
but proc1ucing increased daily gains. ADO was greater (P < .001) in M2 than
Rand Ml, but the latter twO were similar. Monensin increased (P < .01)
rumina! propionic acid production while acectic and butyric acid were
decreased (P < .01). Within L heifers, condition scores were greater (p< .01)
in the M1 and M2 groups compared with R. In H heifers. condition score
was greater (P < .01) for the M2 group than either Ml or R. Hip height was
not affected by treatment, but H heifers were taller (p < .01) than L heifers.
During the feeding period, 92% of M2L and 100% of all other groUps
reached puberty. In the L group, pubertal age and weight were similar
across treatments. However. in the H group. M1 anel M2 heifers were 14
days younger (P < .06) at puberty than R heifers and M2 heifers were
heavier (P < .01) at puberty than Ml and R heifers.. Pregnancy rates were
not different between treatments. In conclusion. monensin decreased ageal
puberty indepenelent of increased ADO or body weight; however, tl1is
effect was only present in the H group. Itappears that H heifers possess an
inherently greater growth Potential than L heifers, and this increase cannot
be explained by differences in body weight .

EFFECTS OF REPE1lTIVE ELF.(:TROSH~G O~ ~H
POPlJ'LHIOXS IX' EXPERl\1E.'TAL RACEWAYS .-\.'1) _\
S!\1ALL HE.U>WATER STREA.\1 ~ SOl.'nIER.~ WEST
VlRGL'\1A Order ='0. 8110474
SAL'l.., GARY Ew., PH.D. Yirgini4 Polytechnic Institute and SIiJl( .
Univo:riry,1980. 152pp.. .,. ..
FIsheries scientists have utilized electrofishing extensively to sample anQ
assess aquatic populations. The physiological responsesoffish~posed to
electroshock ranges from sensor)' recognition. through electrotaxis and
electronarcosis, to death. This study examined the etfects of repetiti\'e
electroshocking over time on population survival, and the etfects of
mortality on the estimation of population size using single. .tenS\ilS.. multiple
census and depletion techniques. .. u' ..
Highly significant differences (P < 0.01) were seen ben;een the number
of shocks a population of fathead minnows (Pimephales promeJas) received
per day and the survi\'al of those fish. Populations recehing the two control