scholarly journals OESTRUS SYNCHRONIZATION, ARTIFICIAL INSEMINATION AND EARLY REBREEDING IN YANKASA SHEEP

2021 ◽  
Vol 9 (2) ◽  
pp. 107-111
Author(s):  
O. A, OSINOWO
Keyword(s):  
Artificial Insemination ◽  
Production System ◽  
Post Treatment ◽  
Natural Mating ◽  
Sheep Production ◽  
Lambing Rate

COMPONENTS of an intensive sheep production system including oestrus synchronization, artificial insemination and early rebreeding were investigated in two trials with Yankasa sheep. Treatment of ewes with progrestagen pessaries for 12 days resulted in good synchronization of first and second post-treatment oestrus. In Trial I, (January–February, 1982) 33 ewes were treated, of which 81.8% showed oestrus within 4 days after the end of progrestagen treatment while 72.7% showed a second oestrus within 21 days. In Trial II, (August – September, 1982), 48 eyes were treated, of which 87.5 and 77.1% showed first and second oestrus respectively over the same periods as in Trial I. Mean interval (± s.e.m) between first and second induced oestrus in both trials was 16.4 ±0.1 days (n = 61). About 90% of ewes exhibiting oestrus were detected 2 to 4 and 17 to 20 days after progrestagen treatment for first and second oestrus respectively.  Lambing reates of ewes to artificial insemination or natural mating at the second induced oestrus in Trial I were 50.0 and 91.7% respectively, Corresponding lambing rates in Trial II were 65.0 and 86.70%.  Rebreeding interval in ewes which lambed in Trial I was 59.1 ±0.8 days following commencement of progestagen treatment approximately one month after lambing. Lambing rate in this group was 78.6%.

Reproductive performance in the Sheep CRC Information Nucleus using artificial insemination across different sheep-production environments in southern Australia

2014 ◽  
Vol 54 (6) ◽  
pp. 715 ◽  
Author(s):  
K. G. Geenty ◽  
F. D. Brien ◽  
G. N. Hinch ◽  
R. C. Dobos ◽  
G. Refshauge ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Artificial Insemination ◽  
Reproductive Rate ◽  
Industry Standards ◽  
Frozen Semen ◽  
Production Environments ◽  
Natural Mating ◽  
Sheep Production ◽  
Reproductive Rates ◽  
Birth Type

The present paper covers reproductive performance in an artificial-insemination (AI) program of the Sheep CRC Information Nucleus with 24 699 lambs born at eight locations in southern Australia across five lambings between 2007 and 2011. Results from AI with frozen semen compared well with industry standards for natural mating. Conception rates averaged 72%, and 1.45 lambs were born per ewe pregnant for Merino ewes and 1.67 for crossbreds. Lamb deaths averaged 21% for Merino ewes and 15% for crossbreds and 19%, 22% and 20% for lambs from ewes that were mated to terminal, Merino and maternal sire types, respectively. Net reproductive rates were 82% for Merino ewes and 102% for crossbreds. From 3198 necropsies across 4 years, dystocia and starvation-mismothering accounted for 72% of lamb deaths within 5 days of lambing. Major risk factors for lamb mortality were birth type (single, twin or higher order), birthweight and dam breed. Losses were higher for twin and triplet lambs than for singles and there was greater mortality at relatively lighter and heavier birthweights. We conclude that reproductive rate in this AI program compared favourably with natural mating. Lamb birthweight for optimum survival was in the 4–8-kg range. Crossbred ewes had greater reproductive efficiency than did Merinos.

Reproduction in young female sheep induced to breed at various ages

1978 ◽  
Vol 26 (3) ◽  
pp. 309-316 ◽  
Author(s):  
R. M. H. Al-Wahab ◽  
M. J. Bryant
Keyword(s):  
Artificial Insemination ◽  
Hormone Treatment ◽  
Young Female ◽  
Post Treatment ◽  
Natural Occurrence ◽  
Natural Mating ◽  
Female Sheep

AbstractTwo hundred and thirteen Suffolk × (Cadzow Improver × Scottish Blackface) young female sheep were mated either after the natural occurrence of puberty or at 140, 182 and 224 days of age in Year 1 and 140 and 182 days of age in Year 2 after treatment with progestagen (MAP) and 750 i.u. PMS; 90 to 100% of sheep ovulated after hormone treatment. Few sheep were found with embryos or live lambs in Year 1, possibly because of inadequacies in artificial insemination. In Year 2, after natural mating, the incidences of cleaved ova, live embryos 26 days after mating and live lambs born were 82, 33 and 23% respectively for sheep mated at 140 days; 100, 31 and 23% respectively for sheep mated at 182 days; and 100, 62 and 31% respectively for sheep mated after puberty. The occurrence of a second post-treatment ovulation in sheep without embryos at 26 days increased with age at treatment.

COMPARISON OF ARTIFICIAL INSEMINATION AND NATURAL MATING ON REPRODUCTIVE PERFORMANCE OF FIVE STRAINS OF SHEEP DURING THE ANESTROUS SEASON IN AN INTENSIVE SYSTEM

1979 ◽  
Vol 59 (4) ◽  
pp. 675-683 ◽  
Author(s):  
A. J. HACKETT ◽  
H. A. ROBERTSON ◽  
E. K. INSKEEP ◽  
J. N. B. SHRESTHA ◽  
M. S. WOLYNETZ
Keyword(s):  
Reproductive Performance ◽  
Artificial Insemination ◽  
Hormone Treatment ◽  
Corpora Lutea ◽  
Blood Samples ◽  
Natural Mating ◽  
Main Effects ◽  
Mating Method ◽  
Intensive System

Synchronized estrus and ovulation were induced during the anestrous season (April–May 1974) in 373 ewes of three synthetic (one sire and two dam) strains and two unselected (Suffolk and Finnish Landrace) purebred strains by treatment with 30 mg fluorogestone acetate (FGA) impregnated in polyurethane intravaginal sponges for 12 days. Following sponge removal each ewe received 500 IU pregnant mares’ serum gonadotrophin (PMSG) IM. Of these, 167 were bred by artificial insemination (AI) at 48 and 60 h post sponge removal with 0.2 ml raw unextended semen collected by electroejaculation (EE). Five days after AI, ewes were exposed to a follow up ram for 16 days for subsequent mating if a second estrus occurred. The remaining 206 were exposed to rams for a period of 22 days for natural mating. Blood samples were collected from 69 ewes, 9, 19 and 27 days post sponge removal and analyzed for progesterone to ascertain if corpora lutea were formed and whether the ewes recycled. The age of ram by mating method interaction significantly affected both fertility and fecundity mainly because some of the younger rams lacked libido and experience for natural mating. There were no significant differences in prolificacy due to any of the main effects tested. Among the 69 ewes examined for progesterone levels, 93% had formed corpora lutea after hormone treatment and 16% recycled. Only 16 of the 255 ewes that did not conceive to the synchronized estrus lambed to the subsequent estrus.

Performance of and factors affecting the small-holder sheep production system in Egypt

1996 ◽  
Vol 19 (2) ◽  
pp. 97-102 ◽  
Author(s):  
E.S.E. Galal ◽  
H.R.M. Metawi ◽  
A.M. Aboul-Naga ◽  
A.I. Abdel-Aziz
Keyword(s):  
Production System ◽  
Factors Affecting ◽  
Sheep Production ◽  
Small Holder

Ovarian regulation of sperm progression in the Fallopain tubes

Zygote ◽  
1994 ◽  
Vol 2 (4) ◽  
pp. 363-366 ◽  
Author(s):  
R. H. F. Hunter
Keyword(s):  
Artificial Insemination ◽  
Fallopian Tubes ◽  
Sperm Transport ◽  
Sperm Suspension ◽  
Essential Components ◽  
Natural Mating ◽  
The 1950S ◽  
1960S And 1970S

Successful liberation and apposition of gametes are essential components of fertility. Normal fertilisation depends upon the establishment of a pre-ovulatory sperm gradient in the female tract between the site of semen deposition and the site of fertilisation in the Fallopian tubes. As a consequence, sperm: egg ratios may be close to unity at the time of activation of most secondary oocytes under conditions of spontaneous mating. In the absence of a sufficient sperm gradient, newly ovulated eggs would be confronted by an excess of spermatozoa resulting in polyspermic fertilisation. Penetration of the vitellus by more than one spermatozoon is pathological in mammals (Beatty, 1957; Austin, 1963). Accordingly, systems that act to regulate sperm progression and competence before the time of ovulation assume a particular importance. During the 1950s, 1960s and 1970s, there was much controversy as to the rate of sperm transport into the Fallopian tubes. Because observations failed to focus on those spermatozoa that could fertilise eggs, the controversy was largely sterile. Nor were the disagreements well founded since some experiments employed artificial insemination whilst others used natural mating. These two quite distinct approaches to introducing a sperm suspension into the female tract could not reasonably form the basis of disagreements on the physiological events of cellular progression. More recent studies have been set in perspective by Overstreet (1983), Harper (1988), Yanagimachi (1988), Hunter (1988, 1991, 1995) and Drobnis & Overstreet (1992)After mating at the onset of oestrus, ram and bull spermatozoa require a minimum of 6–8 h to reach the Fallopian tubes in sufficient numbers to promote suc.cessful fertilisation (Hunter et al., 1980; Hunter & Wilmut, 1982). Spermatozoa displaced to the tubes in a small number of minutes are moribund or dead, not.

Some consequences of high flock prolificacy in an intensive grassland sheep production system

1975 ◽  
Vol 20 (2) ◽  
pp. 219-232 ◽  
Author(s):  
T. G. Boaz ◽  
W. M. Tempest
Keyword(s):  
Perinatal Mortality ◽  
Breeding Season ◽  
Litter Size ◽  
Growth Rates ◽  
Production System ◽  
Late Pregnancy ◽  
Optimal Level ◽  
Fleece Weight ◽  
Sheep Production ◽  
Lamb Growth

SummaryAn intensive sheep production system using flocks of 100 Scottish Halfbred (SHB), 100 Welsh Speckleface (WSF) and 100 Finn Blackface (FBF) ewes maintained by 8, 4 and 6 ha grassland respectively for a 5-year period, was investigated to establish the consequences of high flock prolificacy and the measures taken to achieve it, including PMS administration. Mating occurred in late October/November at ewe: ram ratios of 25 or 33: 1. Ewes were housed in winter and fed silage, with supplementary cereals in late pregnancy. Lambs in excess of 2 (SHB) and 1 (WSF and FBF) per ewe were artificially reared and fattened indoors; ewes and lambs at grass were rotationally grazed (with forward creep grazing by the lambs). Prolificacy in the SHB breed was 225 lambs born per 100 ewes mated for untreated ewes and 237 for hormone-treated ewes; 119 and 155 respectively for WSF ewes; and 255 for FBF ewes (all untreated). Lambs sold per 100 ewes mated were: for SHB, 200 and 177; WSF, 102 and 107; FBF, 201.Good ewe condition and heavy live weights at mating were associated with appetite problems on silage in late pregnancy; PMS injection with a failure to secure conception rates above 80% at the critical oestrus and a markedly lower prolificacy for ewes conceiving at later oestruses; mating in the middle of the breeding season and March/April lambing with slow lamb growth rates on grass in July and August. Hormone-induced high prolificacy was associated with a greater proportion of large multiple litters than natural high prolificacy, and consequent smaller lamb birth weights and more perinatal mortality. There was a significant negative regression relating fleece weight with litter size. The results suggest the existence of an optimal level of prolificacy for the system employed.

Factors affecting reproductive performance of white-tailed deer subjected to fixed-time artificial insemination or natural mating

2013 ◽  
Vol 25 (3) ◽  
pp. 581 ◽  
Author(s):  
Miguel Mellado ◽  
Claudia G. Orta ◽  
Eloy A. Lozano ◽  
Jose E. García ◽  
Francisco G. Veliz ◽  
...  
Keyword(s):  
Litter Size ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Arid Environment ◽  
Factors Affecting ◽  
Litter Weight ◽  
Subsequent Period ◽  
Natural Mating ◽  
Game Hunting

The objectives of this study were to examine the effects of several factors affecting fawning rate, litter size, litter weight and neonatal fawn mortality in white-tailed deer inseminated either transcervically or by means of laparoscopy. Oestrus synchronisation with a controlled internal drug release (CIDR)-based protocol and fixed-time artificial insemination (FTAI) was conducted in 130 white-tailed deer (Odocoileus virginianus texanus) during three reproductive seasons (2007–2009; 271 services) in a game-hunting ranch in a hot–arid environment (26°4′ N, 101°25′ W). Ninety additional non-treated does were exposed to bucks for natural mating. Fawning rate did not differ between AI methods (40.0 vs 45.0% for transcervical and laparoscopic AI, respectively). Overall fawning rate (proportion of all does fawning after FTAI and a subsequent period of buck exposure) did not differ between transcervical (89.5%), laparoscopic (80.3%) or natural (88.9%) insemination. Litter size per fawning doe was higher (P<0.05) in naturally-served does (1.65±0.48) than in transcervically-inseminated does (1.40±0.51) or in laparoscopically-inseminated does (1.48±0.50). The main conclusion was that no enhancement of fawning rate or litter size occurred as a result of intrauterine deposition of semen by laparoscopy compared with the transcervical insemination technique.

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