Effect of constant-release melatonin implants on the onset of oestrous activity and on reproductive performance in the ewe

1991 ◽  
Vol 52 (3) ◽  
pp. 489-497 ◽  
Author(s):  
L. A. Durotoye ◽  
R. Rajkumar ◽  
C. M. Argo ◽  
R. Nowak ◽  
G. E. Webley ◽  
...  
Keyword(s):  
Breeding Season ◽  
Reproductive Performance ◽  
Early Summer ◽  
Late Spring ◽  
Multiple Births ◽  
Melatonin Treatment

ABSTRACTVarious types of constant-release melatonin implants were designed and administered to adult ewes during seasonal anoestrus. Implants were given between May and July in a series of four experiments. Treatment of ewes with melatonin implants resulted in advancement of the onset of oestrous activity. Melatonin treatment also resulted in improved reproductive performance, increased numbers of lambs born per ewe bred and caused more multiple births. Results from this study show, therefore, that constant-release melatonin implants administered during late spring or early summer advance the onset of the breeding season and improve reproductive performance in ewes.

Effects of melatonin implantation on the fertility potentials of Kivircik and Charollais ewes and rams during the non-breeding season

2017 ◽  
Vol 20 (3) ◽  
pp. 501-506 ◽  
Author(s):  
M. Cevik ◽  
C. Yilmazer ◽  
A. Kocyigit
Keyword(s):  
Pregnancy Rate ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Reproductive Potential ◽  
Testicular Volume ◽  
Melatonin Treatment ◽  
Scrotal Circumference ◽  
Estrus Response

AbstractThis study examined the effect of melatonin implantation during the non-breeding season on the reproductive performance of ewes and the testicular dimensions of rams. In seasonally anestrus Kivircik and Charollais ewes and rams were subjected to melatonin. Estrus response was significantly higher in treated than control ewes of both breeds (p<0.001). The pregnancy rate was significantly lower (p<0.001) in the control than in the treated animals. The twinning rate was significantly lower in melatonin implanted Kivircik than Charollais ewes (p<0.05). The testicular dimensions after 42 days of melatonin treatment increased in both breeds. Scrotal length (SL) increased in Kivircik and Charollais rams (p<0.01). The increase in scrotal circumference (SC) was more marked in the Charollais (P<0.01) than in the Kivircik rams. There was a large increase in testicular volume (TV) in both Kivircik (p<0.01) and Charollais (p<0.001) rams. This study shows that melatonin implants can be applied to induce estrus in ewes approximately four months earlier than breeding season. Melatonin implantation in the non-breeding season significantly increased testicular dimensions in Kivircik and Charollais rams thus increasing their reproductive potential.

Effect of treatment with melatonin implants in conjunction with teaser rams on the reproductive performances of Poll Dorset x Merino ewes joined in early summer in the south-west of Western Australia

1992 ◽  
Vol 32 (8) ◽  
pp. 1045 ◽  
Author(s):  
KP Croker ◽  
MA Johns ◽  
AH Williams ◽  
SR McPhee ◽  
LD Staples
Keyword(s):  
Reproductive Performance ◽  
Reproductive Activity ◽  
Early Summer ◽  
The Other ◽  
Control Group ◽  
Melatonin Treatment ◽  
South West ◽  
Effect Of Treatment ◽  
First Time ◽  
Teaser Rams

Melatonin pretreatment to improve the reproductive performance of first-cross Poll Dorset x Merino ewes joined in early summer was investigated in 2 experiments conducted in consecutive years. In experiment 1, melatonin pellets were administered subcutaneously to 1 of 3 groups of ewes; 14 days later they were joined with testosterone-primed wethers ('teasers'), followed after 15 days by entire rams (melatonin-teased group). The other groups were untreated and teased only. Experiment 2 consisted only of teased and melatonin-teased groups, with the ewes from experiment 1 being reallocated, as well as maiden ewes being joined for the first time. In this experiment melatonin pellets were inserted 38 days before the start of joining. Treatment with melatonin resulted in increased reproductive performances. The responses were characterised by an earlier (P<0.05) conception pattern in both experiments and higher (P<0.001) lambing percentages than controls in experiment 1. Up to 22% more lambs were born to melatonin-teased ewes than to teased ewes, and stimulatory effects were similar for ewes of different ages. In experiment 2, ewes that had received melatonin in both experiments tended (P>0.05) to have higher lambing percentages than teased ewes (up to 17% more lambs born), while ewes that had received melatonin in only experiment 1 tended (P>0.05) to have lower lambing percentages than ewes that were not treated with melatonin in either experiment (4-11%). The higher lambing performances of the melatonin-treated ewes were independent of ewe liveweights. Reproductive activity was also stimulated by the use of teasers alone in experiment 1. Conception patterns were advanced (P<0.01) and there was a trend for more (P>0.05) lambs to be born in the teased group than in the control group. The results show that both teasers and melatonin treatment will advance the conception patterns of first-cross Poll Dorset x Merino ewes joined in early summer, but the melatonin treatment also stimulated fecundity.

scholarly journals Effects of melatonin treatment on milk traits, reproductive performance and immune response in Sarda dairy sheep

2021 ◽  
Vol 20 (1) ◽  
pp. 632-639
Author(s):  
Giovanni Cosso ◽  
Maria Consuelo Mura ◽  
Luisa Pulinas ◽  
Giulio Curone ◽  
Daniele Vigo ◽  
...  
Keyword(s):  
Immune Response ◽  
Reproductive Performance ◽  
Dairy Sheep ◽  
Melatonin Treatment ◽  
Milk Traits

scholarly journals Effects of management system on beef heifer growth and reproductive performance

2020 ◽  
Author(s):  
Parker A Henley ◽  
Frank A Ireland ◽  
Igor F Canisso ◽  
J Lannett Edwards ◽  
Daniel W Shike
Keyword(s):  
Development Strategy ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Body Condition Score ◽  
Pregnancy Rates ◽  
Fescue Toxicosis ◽  
Soybean Hulls ◽  
Randomized Design ◽  
Condition Score ◽  
Calf Performance

Abstract This study evaluated the effect of heifer development system on body weight (BW), body condition score (BCS), fescue toxicosis symptoms, reproductive performance, and subsequent calf growth of fall-calving beef heifers. Angus × Simmental heifers [n = 399; 240 ± 20.0 kg initial BW; age = 252 ± 20 d] were stratified by BW and BCS and assigned to 1 of 12 groups in each of the 2 production years. The study utilized a stratified randomized design. Pens were randomly assigned to 4 treatments: drylot (DL) development (fed ad-libitum diet consisting of 90% hay and 10% DDGS on a dry matter basis), grazing endophyte-infected fescue supplemented daily (2.3 kg as-fed/heifer/d; 50:50 mix of soybean hulls and DDGS; E+/S), grazing endophyte-infected fescue and supplemented from the midpoint of treatment period until breeding (4.5 kg as-fed/heifer/d; 50:50 mix of soybean hulls and DDGS; E+/LS), and grazing novel endophyte-infected fescue with no supplement (NE+/NS). Treatments ceased on d 168 [time of artificial insemination (AI)] and heifers were commingled and managed as a group through second breeding season. Heifers in DL had greatest (P ≤ 0.05) BW and BCS from d 28 until d 254. Furthermore, E+/S heifers had greater (P ≤ 0.05) BW and BCS than both E+/LS and NE+/NS from d 28 until d 168. On d 56 and 84, E+/LS heifers had lower (P ≤ 0.05) BW and BCS compared to NE+/NS, but on d 148 treatments reranked and E+/LS remained at a greater (P ≤ 0.05) BW and BCS compared to NE+/NS through the first breeding season. Drylot heifers had greatest (P ≤ 0.05) percentage cycling and percentage of mature BW at AI (66.6%) and had greater (P ≤ 0.05) AI and overall pregnancy rates compared to E+/LS and NE+/NS. The E+/S (55%) and E+/LS (53.7%) heifers were developed to a greater (P &lt; 0.01) percentage of mature BW than NE+/NS (49.3%). A greater (P ≤ 0.02) percentage of DL and E+/S heifers were pregnant at the end of the first breeding season (89.3 and 85.1%; respectively) compared to NE+/NS (61.5%). In summary, DL heifers had the greatest BW and BCS at AI, percentage cycling, and AI pregnancy rate. However, this strategy did not result in differing overall pregnancy rates between DL, E+/S, and E+/LS and there were no differences in milk production, rebreeding reproductive performance, and calf performance between all treatments. Finally, the poorest AI and overall pregnancy rates of the NE+/NS heifers suggests this is not a viable development strategy for fall-born heifers.

The effect of melatonin treatment during the seasonal anoestrus on the superovulatory response and embryo production of high-prolificacy Rasa Aragonesa ewes before culling

2003 ◽  
Vol 2003 ◽  
pp. 82-82
Author(s):  
F. Forcada ◽  
J.A. Abecia ◽  
J.A. Valares
Keyword(s):  
Embryonic Development ◽  
Breeding Season ◽  
Litter Size ◽  
Direct Effect ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Melatonin Treatment ◽  
Embryo Production ◽  
Spring Equinox

The efficacy of melatonin implants inserted around the spring equinox to improve fertility and ovulation rate or litter size in Mediterranean ewes has been previously reported (Chemineau et al., 1996; Forcada et al., 2002a.), indicating the ability of the hormone to regulate the hypothalamic activity (Viguié et al., 1995). Moreover, a direct effect of melatonin on corpora lutea and embryonic development has been also reported (Wallace et al., 1988; Abecia et al., 2002). The use of prolific Rasa Aragonesa (RA) ewes (a Mediterranean breed) before culling as embryo donors has been previously tested in the breeding season (Forcada et al., 2002b.). The aim of this experiment was to improve embryo production during the seasonal anoestrus period in selected superovulated RA ewes at the end of their reproductive lives through the use of melatonin.

scholarly journals MANAGEMENT OF LATE SPRING-EARLY SUMMER PASTURE SURPLUSES IN HILL COUNTRY

1984 ◽  
pp. 199-206 ◽  
Author(s):  
G.W. Sheath ◽  
R.W. Webby ◽  
W.J. Pengelly
Keyword(s):  
Early Spring ◽  
Early Summer ◽  
Late Spring ◽  
First Year ◽  
Hill Country ◽  
Continuous Grazing ◽  
Summer Pasture ◽  
Animal Performances ◽  
Grazing Policy ◽  
Made In

Comparisons of controlling late spring to early summer pasture growth on either easy or steep contoured land with either a fast rotation or continuous grazing policy were made in self-contained farmlets for two years. Pasture control was maintained over more land by controlling steep land first and with continuous grazing. Animal performances (ewes, steers) were generally similar for the mid-November to early January treatment period, and subsequently until May shearing. In the first year better animal performances occurred in "steep control" farmlets during winter and early spring, but this was less evident in the second year. Priority control of steep land during late spring-early summer is recommended because of likely longer-term benefits in pasture composition,density and production. Quick rotation grazing through the period provides a better ability to recognise and manage pasture quantities and should be adopted if summer droughts are anticipated. For well fenced properties in summer-wet areas and with integrated stock grazing, continuous grazing during late spring-early summer may be equally suitable. Keywords: hill country, grazing management, pasture control

Development of a nutritional strategy for increasing lamb survival in Merino ewes mated in late spring/early summer

1998 ◽  
Vol 52 (3) ◽  
pp. 213-219 ◽  
Author(s):  
M.B Nottle ◽  
D.O Kleemann ◽  
V.M Hocking ◽  
T.I Grosser ◽  
R.F Seamark
Keyword(s):  
Early Summer ◽  
Late Spring ◽  
Nutritional Strategy ◽  
Lamb Survival
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