An Evaluation Of Factors Affecting Repeatability Of Litter Size Of Semi-Intensively Managed Ewes In Sub-Humid Zone Of South Western Nigeria

2005 ◽  
Vol 53 (3) ◽  
Author(s):  
AR Abdullah ◽  
BO Emikpe ◽  
R Aboujaoude
Keyword(s):  
Litter Size ◽  
Factors Affecting ◽  
Humid Zone ◽  
Intensively Managed

scholarly journals Factors Affecting Days to Conception, Litter Size and Litter Weight of Intensively Managed Canarian Hair Sheep

2010 ◽  
Vol 37 (2) ◽  
pp. 261-264
Author(s):  
L. A. Bermejo ◽  
M. Mellado ◽  
J. Mata ◽  
J. R. Arévalo ◽  
L. De Nascimento ◽  
...  
Keyword(s):  
Litter Size ◽  
Hair Sheep ◽  
Factors Affecting ◽  
Litter Weight ◽  
Intensively Managed

Factors affecting reproductive performance and estimates of genetic parameters of litter size in Horro sheep

2002 ◽  
Vol 139 (1) ◽  
pp. 79-85 ◽  
Author(s):  
S. ABEGAZ ◽  
G. DUGUMA ◽  
E. NEGUSSIE ◽  
U. GELMESA ◽  
F. TEREFE ◽  
...  
Keyword(s):  
Animal Model ◽  
Litter Size ◽  
Age Structure ◽  
Reproductive Performance ◽  
Genetic Improvement ◽  
Genetic Parameters ◽  
Factors Affecting ◽  
Optimal Weight ◽  
Annual Means ◽  
Lambing Rate

Conception and lambing rate, and litter size were studied on data from a flock of Horro sheep. The CATMOD and GLM procedures of SAS were used for the analysis of these traits. A sire, direct additive genetic and a repeatability animal model were employed to obtain estimates of heritability and repeatability for litter size. The results obtained showed that year of mating, age and weight of ewes at mating and number of previous parities had significantly (P<0.01) affected the rate of conception and lambing while weight of rams at mating has shown no significant effect (P>0.05). An increase in both conception and lambing rates was observed with the increase in weight of ewes up to about 36 kg and declined thereafter. Ewes which previously had no or one parity had lower conception and lambing rates compared with ewes in later parities. However, a decline in both conception and lambing rates was also observed in old ewes. Year of lambing, parity and weight of ewes at mating had a highly significant (P<0.01) effect on litter size. The overall mean litter size in the flock was 1.34 with annual means ranging from 1.18 to 1.55. Litter size increased with parity from 1.26 in primiparous ewes to 1.44 for ewes of parities five and above. With respect to weight of ewes at mating, litter size increased by 2.5% for each kg increase in weight at mating. The estimates of direct heritability (h2) for litter size were 0.17, 0.11 and 0.06 under the sire, direct animal and repeatability models. Repeatability was estimated to be 0.12. Since heritability and repeatability estimates of litter size are low, genetic improvement by selection may not bring sizeable impact in increasing litter size. Therefore flock management for optimal age structure and optimal weight of ewes at mating should receive due consideration to improve rates of conception, lambing and litter size in Horro sheep.

Crossbred sheep production I. Factors affecting production from the crossbred ewe flock

1964 ◽  
Vol 6 (1) ◽  
pp. 73-84 ◽  
Author(s):  
B. C. Yalçin ◽  
Maurice Bichard
Keyword(s):  
Body Weight ◽  
Litter Size ◽  
Selective Breeding ◽  
Live Weight ◽  
Correction Factors ◽  
Secondary Product ◽  
Factors Affecting ◽  
Fleece Weight ◽  
Sheep Production

Donald (1962) has recently pointed out the paucity of available data on production from British sheep, though some information is available for hill sheep (see for example Donald, 1958; Purser and Roberts, 1959; Purser and Young, 1959; Dalton, 1962). Most of these refer mainly to the Scottish Blackface and Welsh Mountain breeds. Hill sheep form approximately 40% of the national flock of over 11 million breeding ewes. Another 40% of ewes are found in crossbred flocks mainly kept on the lowlands; these produce fat lambs and hoggets with wool as a secondary product. Very little information has so far been published on these crossbred ewes, exceptions being work reported by Bywater (1945) and Rennie (1957). This is the first of three papers to be presented with the object of providing such information, and is based mainly on the work of Yalçin (1963). It is hoped that these papers will be of use on two counts:1. To provide a documentation of one specific cross, the Border Leicester × Cheviot ewe and her Suffolk-cross lambs under North of England grassland conditions.2. To analyse the usefulness of keeping production records within such flocks as aids to good commercial management, to culling and to selective breeding.In this paper the traits studied are body weight, fleece weight and litter size of the ewes, and the weights of the lambs between birth and slaughter or weaning. Estimates were obtained for the effects upon some of these traits of age and live-weight of ewe, and of sex, year and type of birth and rearing of the lambs. The usefulness of such correction factors is considered within recording schemes. In subsequent papers the effects on production of differences between crossbred ewes and between the rams used as fat lamb sires will be considered.

The biological efficiency of meat production in sheep

1970 ◽  
Vol 12 (3) ◽  
pp. 393-401 ◽  
Author(s):  
R. V. Large
Keyword(s):  
Growth Rate ◽  
Litter Size ◽  
High Growth ◽  
High Growth Rate ◽  
Biological Efficiency ◽  
Meat Production ◽  
Final Size ◽  
Artificial Rearing ◽  
Factors Affecting ◽  
Digestible Organic Matter

SUMMARYThe biological efficiency of meat production (E) is defined as the weight of carcass produced per 100 units of digestible organic matter (DOM) consumed. The factors affecting this relationship, for ewes and lambs, are discussed and the results of experiments are used to demonstrate the effect of number of lambs per year and size of ewe on the value of E. Calculations are made to show the effect on E of other factors such as the growth rate of the lambs and the weight at which the lambs are slaughtered. The general conclusions are that the highest values for E will be obtained from small breeds of ewes producing large litters and crossed with a large breed of ram, leading to a high growth rate and final size in the lamb. A relatively small increase in litter size in the small breeds of ewe (i.e. from one to two lambs) may result in a level of efficiency as high as that achieved by a larger breed with a large litter size (i.e. three to four lambs) without having to resort to techniques such as the artificial rearing of lambs.

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&lt;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.

scholarly journals FACTORS AFFECTING LITTER SIZE IN THE SCOTCH HALF-BRED EWE

Reproduction ◽  
1968 ◽  
Vol 17 (3) ◽  
pp. 485-493 ◽  
Author(s):  
J. E. NEWTON ◽  
J. E. BETTS
Keyword(s):  
Litter Size ◽  
Factors Affecting

Gestation period, litter size and birth weight in the goat

1983 ◽  
Vol 36 (1) ◽  
pp. 105-110 ◽  
Author(s):  
E. A. Amoah ◽  
M. J. Bryant
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Live Weight ◽  
Regression Equation ◽  
Gestation Period ◽  
General Linear ◽  
Factors Affecting ◽  
Interactive Model

ABSTRACTData from 265 female goats (does) from seven herds in Year 1 and 130 does from four herds in Year 2 were analysed using a general linear interactive model for factors affecting gestation period (GP), litter size (LS) and birth weight (BW) of offspring (kids). Gestation period could be described by the regression equation GP = α – 0·890LS –1·072S where S is the proportion of male kids in the litter and the constant (a) depends on breed and herd and was 154·240 (s.e., 0·843) days for British Saanen does in Herd 1. The model established for LS was a quadratic regressional relationship LS = a – 0·000103 (MW - 60))2 + 0-0172 (MW -60) where MW was live weight of the doe at mating and a at MW = 60 kg depends on herd and period of kidding. For early-kidding does in Herd 1 a was 2·277 (s.e., 0·090) kids. The expression BW —α 0·363LS + 0·057P is a simplified multiple regressional form involving BW, LS and parity (P) where a varies according to breed, herd and age of the doe. The estimate of a for kids from British Saanen, 1-year-old does in Herd 1 was 3·879 (s.e., 0·632) kg.

scholarly journals Descriptive characterization of a nigerian heterogeneous rabbit population - factors affecting litter traits.

2010 ◽  
Vol 18 (2) ◽  
pp. 111
Author(s):  
S.O. Oseni ◽  
B.A. Ajayi
Keyword(s):  
Litter Size ◽  
Reproductive Traits ◽  
Daily Weight Gain ◽  
Average Weight ◽  
Font Size ◽  
Factors Affecting ◽  
Litter Traits ◽  
Nigerian Population ◽  
Size At Birth

<span style="font-size: small;"><span style="font-size: 13px; line-height: 14px;">Thi study evaluated the effect of female body weight at conception (FWC), season of mating (SM), type of mating (TM) and litter size at birth (LSB) on the litter performance in a heterogeneous Nigerian population of rabbits. Data on 116 litters from 10 bucks and 48 does across three parities were analysed. Reproductive traits evaluated included LSB, number born alive (NBA), litter sizes and weights at 7, 14 and 21 d post-kindling, pre-weaning survival rate (SR) and daily weight gain of kits from kindling to weaning (DWG). A fi xed linear model that included FWC (light and heavy does), TM (homospermic and heterospermic matings), LSB classes (low, medium and large) and SM (rainy or dry) was used. Results showed that heavier does at concenption showed higher performance for LSB and NBA (P&lt;0.05) than lighter does. Average weight of kits at kindling and at 28 d, as well as kit SR and DWG, were signifi cantly higher in low-sized litters, when compared with intermediate- and large-sized litters (P&lt;0.05). LSB, NBA and litter size at weaning were higher in litters produced by heterospermically mated does compared with homospermically mated does. Season of mating affected LSB and NBA (P&lt;0.05), being signifi cantly larger the litters in the rainy season.</span></span>

scholarly journals Effects of breed, management system, milk yield and body weight on onset of postpartum ovarian cyclicity in cows

2016 ◽  
Vol 32 (1) ◽  
pp. 27-34
Author(s):  
SN Saha ◽  
MGS Alam ◽  
M Shamsuddin ◽  
M Khatun
Keyword(s):  
Body Weight ◽  
Ovarian Function ◽  
Ovarian Activity ◽  
Factors Affecting ◽  
Lower Body Weight ◽  
Holstein Friesian ◽  
Body Weights ◽  
Intensively Managed ◽  
Ovarian Cyclicity ◽  
Zebu Cows

To determine the factors affecting onset of postpartum ovarian cyclicity (PPOC) milk progesterone concentrations were measured in 84 cows. About 30% showed cyclicity within 120 days of parturition. Intensively managed cows started cyclicity earlier (P>0.05) than extensively managed animals. Holstein-Friesian crossbred cows started ovarian cyclicity earlier (80.2 ± 17.5 days) with higher proportion (37.9%) than local zebu cows (84.8 ± 21.0 days) and about 13.3%, respectively (P>0.05). The cows yielding 4-12 kg milk/day required 73.5 ± 10.0 days to start ovarian function earlier than those producing 1-2 kg/day (84.8 ± 21.0 days) (P>0.05). Cows with lower (<200 kg) and higher (>300 kg) body weights started ovarian activity by 81.6 ± 16.6 and 76.3 ± 17.4 days, respectively (P>0.05). Cows with lower body weight showed PPOC at lower rate (5.2%) than those of medium (38.3%) and higher body weight (33.3%) (P<0.05). The delayed onset of PPOC prolonged the calving interval.Bangl. vet. 2015. Vol. 32, No. 1, 27-34

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