Reproductive performance and productive traits of beef bulls selected for different levels of testosterone response to GnRH

1987 ◽  
Vol 27 (2) ◽  
pp. 317-328 ◽  
Author(s):  
T.B. Post ◽  
H.R. Christensen ◽  
G.W. Seifert
2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Aqeel H. Al Jothery ◽  
Lobke M. Vaanholt ◽  
Nimesh Mody ◽  
Anis Arnous ◽  
Jens Lykkesfeldt ◽  
...  

1992 ◽  
Vol 72 (1) ◽  
pp. 23-30
Author(s):  
J. W. Wilton ◽  
M. R. McMorris

The fertility of beef bulls which completed performance test in the Ontario Bull Test Program was measured by classification of success as breeders according to surveys of consignors to test, by classification of satisfaction in surveys of users of tested bulls and by measurement of calf crop percentages and birth dates of progeny relative to herdmates in the Ontario Beef Herd Improvement Program. Consignors classified 3.0% of the 2556 bulls with completed information as unsuccessful breeders. Users rated 61.5% of the 411 bulls with information from the participant survey as very satisfactory and 4.5% as very unsatisfactory. The effects of end of test weight, gain index, backfat and scrotal circumference on calf crop percentage (cows calving relative to cows exposed), percent of calves born in the first 3 wk of the calving season, percent of calves born in the first 12 wk and satisfaction score were generally small and nonsignificant as tested within breed for 122 Angus, 451 Charolais, 632 Hereford, 575 Limousin and 501 Simmental bulls. In general, gain on test and end-of-test measurements were not found to have any association with subsequent fertility of bulls tested. There was no evidence that increased scrotal circumferences were associated with increased measures of productive performance nor that increased fatness, within the range included in the Ontario Bull Test Program, decreased reproductive performance. Key words: Fertility, genetic evaluation, scrotal circumference, backfat


2007 ◽  
Vol 4 (2) ◽  
pp. 125
Author(s):  
N.B.P Utomo ◽  
M. Zairin Junior ◽  
T.L. Yusuf ◽  
I. Mokoginta ◽  
M. Bintang

<p>This experiment was conducted to determine the dietary Vitamin E requirement for reproduction of broodstock zebrafish Danio rerio.  Four isonitrogenous (39% crude protein) and isocaloric (3,260 kcal digestible energy/kg diet) practical diets, namely diets A, B, C, and D with different levels of Vitamin E were fed to zebrafish broodstock.  The broodstock were cultivated in aquaria.  Diet A contained low dosage of Vitamin E (5 mg Vitamin E /kg diet), while diets B (62 mg Vitamin E /kg diet), C (125 mg Vitamin E /kg diet), and diet D (187 mg Vitamin E /kg diet), combined respectively with 1% n-3 fatty acids and 2% n-6 fatty acids.  Fish were fed ad satiation for 60 days using these diets.  During feeding period, gonad maturation stages were examined.  The dietary with different level of Vitamin E affected egg size, chemical content, total number of larvae, normal larvae, and survival rate of larvae produced, fecundity, fertilization rate, and hatching rate.  On the other hand, fish fed on experimental diets did not show any significance differences in the gonad somatic index, fecundity, fertilization rate, and hatching rate.  Fish fed on diet D produced the highest fecundity (633.65 ± 71.86 eggs/grams of fish), fertilization rate (92.3 ± 7.7%), and hatching rate (80.31 ± 9.8%).  The total lipid content of eggs were significant, ranging from D (39.7%), C (33.5%), B (32.1%), and A (29.5%).  At a dosage of 1% of dietary n-3 fatty acids and 2% n-6 fatty acids, zebrafish require 187 mg Vitamin E/kg feed in the diet for reproduction.  .</p> <p>Keywords:  vitamin E, reproductive performance, Danio rerio</p> <p> </p> <p>ABSTRAK</p> <p>Penelitian ini ditujukan untuk mengetahui kebutuhan Vitamin E pada pakan induk ikan zebra (Danio rerio) untuk reproduksi.  Empat pakan perlakuan yang iso-protein (39%) dan iso-kalori (3.260 kcal digestible energy/kg pakan), dinamakan pakan A, B, C, dan pakan D dengan kandungan Vitamin E yang berbeda diberikan kepada induk ikan zebra.  Induk ikan dipelihara pada akuarium.  Pakan A mengandung Vitamin E terendah (5 mg Vitamin E/kg pakan), sedangkan pakan B mengandung Vitamin E 62 mg Vitamin E/kg pakan, pakan C asam mengandung Vitamin E 125 mg /kg pakan, dan pakan D mengandung Vitamin E 187 mg /kg pakan.  Semua pakan perlakuan mempunyai kombinasi asam lemak n-3 berbanding n-6 sebesar 1:2.  Ikan diberi pakan secara ad satiation selama 60 hari pemeliharaan.  Selama masa pemberian pakan, tingkat kematangan gonad diperiksa secara teratur.  Perbedaan kandungan vitamin E dalam pakan mempengaruhi fekunditas, derajat pembuahan telur, serta derajat penetasan telur.  Pakan perlakuan tidak mempengaruhi nilai gonad somatik indeks dan kelangsungan hidup larva umur 3 hari.  Pemberian pakan D menghasilkan fekunditas (633.65 ± 71.86  telur/gram induk), derajat pembuahan telur (92.3 ± 7.7%), serta derajat penetasan telur (80.31 ± 9,8%) terbaik.  Total kandungan lemak pada telur berbeda nyata, yaitu pada pakan D (39.7%), C(33.5%), B(32.1%), dan pakan A(29.5%).  Pada kandungan 1% asam lemak n-3 dan 2% asam lemak n-6, ikan zebra membutuhkan 187 mg Vitamin E/kg pakan untuk reproduksi yang normal. </p> <p>Kata kunci:  Vitamin E, penampilan reproduksi, Danio rerio</p>


2020 ◽  
Vol 10 (4) ◽  
pp. 565-570
Author(s):  
Setsumi Molapo Motsoene ◽  
Edward Webb ◽  
Motselisi Aloycia Mahlehla ◽  
Thato Chabeli ◽  
Paseka Kompi

2005 ◽  
Vol 17 (4) ◽  
pp. 479 ◽  
Author(s):  
G. M. Schuenemann ◽  
J. L. Edwards ◽  
F. M. Hopkins ◽  
N. R. Rohrbach ◽  
H. S. Adair ◽  
...  

During a 2-year study, yearling beef bulls were used to determine the effects of grazing on endophyte-infected tall fescue on endocrine profiles, semen quality and fertilisation potential. Bulls were allotted to graze tall fescue pastures infected with Neotyphodium coenophialum (E+; n = 20 per year) or Jesup/MaxQTM (Pennington Seed, Atlanta, GA, USA; NTE; n = 10 per year). Bulls were grouped by scrotal circumference (SC), bodyweight (BW), breed composites and age to graze tall fescue pastures from mid-November until the end of June (within each year). Blood samples, BW, SC and rectal temperatures (RT) were collected every 14 days. Semen was collected from bulls every 60 days by electroejaculation and evaluated for motility and morphology. The developmental competence of oocytes fertilised in vitro with semen from respective treatments was determined. Bulls grazing E+ pastures had decreased BW gain (P < 0.01), increased overall RT (P < 0.01) and decreased prolactin (P < 0.01) compared with animals grazing NTE pastures. Neither percentage of normal sperm morphology nor motility differed between bulls grazed on the two pasture types. Semen from E+ bulls demonstrated decreased cleavage rates (P = 0.02) compared with semen from NTE bulls. However, development of cleaved embryos to the eight-cell and blastocyst stages did not differ between the two groups. In conclusion, semen from bulls grazing E+ tall fescue resulted in decreased cleavage rates in vitro, which may lower reproductive performance owing to reduced fertilisation ability.


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