Some components of reproductive performance of sheep in Victoria

1970 ◽  
Vol 21 (6) ◽  
pp. 945 ◽  
Author(s):  
PD Mullaney ◽  
GH Brown
Keyword(s):  
Reproductive Performance ◽  
Relative Number ◽  
Relative Contribution ◽  
Effect Of Age ◽  
Age Estimates ◽  
Age Structures

Estimates are given of the relative contribution of each component of reproductive performance - the relative number of ewes having no, one, or two lambs - in the effect of age on the number of lambs born per ewe joined for Merino and Corriedale sheep in Victoria. For Merinos, the proportion of ewes giving birth to more than one lamb increased by 0.05 from ages 3 to 6, followed by a decline of 0.02 at age 8. For Corriedales, this proportion increased by 0.06 from age 3 to age 6. The proportion of ewes having no lamb was greater at the maiden lambing (age 3, Merinos; age 2, Corriedales) than at any other age. Estimates of the effect of age on these components are used to assess the reproductive performance of flocks of different age structures.

Genetic and phenotypic parameters for wool characteristics in fine-wool Merino, Corriedale, and Polwarth sheep. I. Influence of various factors on production

1969 ◽  
Vol 20 (6) ◽  
pp. 1161 ◽  
Author(s):  
PD Mullaney ◽  
GH Brown ◽  
SSY Young ◽  
PG Hyland
Keyword(s):  
Reproductive Performance ◽  
Performance Data ◽  
Reproductive Status ◽  
Wool Production ◽  
Wool Quality ◽  
Effect Of Age ◽  
Age Structures

Estimates are given of the change in the level of production of 10 fleece characteristics of four Merino, one Polwarth, and three Corriedale flocks, in Victoria associated with variation in property, breed, season, property x season, age, and reproductive status. There was a decrease with age of characteristics associated with wool weight, and a decline in general wool quality. The decline was approximately linear for most characteristics from ewes of 3 years of age. Lactation was generally more severe than pregnancy in reducing wool production. The estimates of the effect of age on wool characteristics are used to assess the likely quantity and quality of wool produced by flocks of different age structures. These estimates may be used in conjunction with reproductive performance data to plan for maximum wool production.

Cumulative reproductive performance effect on overall lifetime productivity in Merino sheep

2018 ◽  
Vol 58 (8) ◽  
pp. 1470
Author(s):  
J. S. Richards ◽  
M. A. Sladek ◽  
G. J. Lee
Keyword(s):  
Reproductive Performance ◽  
New South ◽  
Dental Health ◽  
Age Groups ◽  
The South ◽  
Performance Effect ◽  
South West ◽  
South Wales ◽  
The Impact ◽  
Effect Of Age

Reproduction is an important driver of profitability in commercial sheep flocks. Historically, Merino flocks have been run with a fixed age structure, ignoring individual merit and casting for age at a specific age. More recently, research has focussed on utilising the variation within age groups by keeping productive older ewes longer and culling less productive ewes earlier. Previous studies have also examined the effect of age on reproduction and the impact of reproduction status on productivity, but little research has been conducted on cumulative effects of reproductive performance on later productivity, reproduction and health. The present study examined the impact of higher lifetime reproduction on other key production and fitness traits in older ewes run under commercial conditions. Data were collected from two commercial wool-producing properties in the South West Slopes and the Central West Plains of New South Wales during 2009–2011. Reproduction, fleece measurements, bodyweight and condition and dental health were recorded during the study. The results showed that age had a bigger effect on productivity and dental health than did cumulative lifetime reproduction. Environment and genetics determined the level of impact, with minimal loss in productivity from increased age of animals occurring in the South West Slopes flock, whereas the Central West Plains flock would appear to require closer monitoring of productivity as ewes aged. The data collected did not allow separation of the genetic and environmental influences within the study. Retaining animals with a higher reproductive performance past normal culling age does not necessarily result in reduction of productivity or ewe health, but this must be monitored.

scholarly journals Effect of age and backfat thickness on reproductive performance of 100 kg Large White sows

1985 ◽  
Vol 34 (3) ◽  
pp. 365-365
Author(s):  
R. GUEBLEZ ◽  
J. M. GESTIN ◽  
Geneviève LE HENAFF
Keyword(s):  
Reproductive Performance ◽  
Backfat Thickness ◽  
Large White ◽  
Effect Of Age

The influence of age on reproductive performance on sheep in Australia

1969 ◽  
Vol 20 (5) ◽  
pp. 953 ◽  
Author(s):  
PD Mullaney ◽  
GH Brown
Keyword(s):  
Survival Rate ◽  
Reproductive Performance ◽  
Reproduction Rate ◽  
Age Structures

Estimates are given for various traits associated with reproduction rate at each age from 3 to 9, 2 to 7, and 3 to 6 years for Merino, Corriedale, and Polwarth ewes respectively. The number of lambs born per ewe joined for Merino ewes decreased steadily with age, while the number of lambs weaned per ewe joined and the survival rate of both single and twin lambs rose to a peak at 4–5 years, with a subsequent fall; the reproduction rate for Corriedale and Polwarth ewes increased with age to the oldest age of 6 years. The estimates are used to predict the reproduction rate of flocks with different age structures, the conclusion being that the average number of lambs born per ewe joined would decrease progressively with increase in flock age, and the average number of lambs weaned per ewe joined would increase with the age of the oldest group of ewes up to 6 years for Merino flocks, and with the oldest group to at least 6 years for Corriedale and Polwarth flocks.

scholarly journals Effect of age at photostimulation on reproductive performance of Beijing-You Chicken breeders

2019 ◽  
Vol 98 (10) ◽  
pp. 4522-4529 ◽  
Author(s):  
Lei Shi ◽  
Yanyan Sun ◽  
Hong Xu ◽  
Yifan Liu ◽  
Yunlei Li ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Effect Of Age

The effect of age and diet on the reproductive performance of Sudan Nilotic ewes

2005 ◽  
Vol 143 (5) ◽  
pp. 421-426 ◽  
Author(s):  
M. ATTA ◽  
O. A. EL KHIDIR
Keyword(s):  
Reproductive Performance ◽  
Research Centre ◽  
Southern Sudan ◽  
Oil Cakes ◽  
Body Weights ◽  
Sorghum Grains ◽  
Mortality Proportion ◽  
Production Research ◽  
Similar Body ◽  
Effect Of Age

Two flocks of 42 multiparous (M) and 27 primiparous (P) Nilotic ewes (Southern Sudan) were used in an experiment conducted at the Animal Production Research Centre, Khartoum N., Sudan, to study the effect of age and diet on reproductive performance. Each age group (M and P) was subdivided into two diet groups, fed either a sorghum (So) or a molasses (Mo)-based diet. The two diets were approximately isoenergetic (12·2 and 11·4 MJ ME/kg DM for So and Mo diets, respectively) and isonitrogenous (217 g CP/kg). These diets were formulated from sorghum and groundnut cake or molasses and urea as main sources of energy and protein, respectively. Each of the four diet groups of ewes was further divided into 6 subgroups (replicates) of similar body weights housed and fed together for two successive gestation periods. The results showed that the diet treatments had no significant effect on age and weights at first oestrous (210, 238 days and 22, 20 kg) and at first lambing (407, 418 days and 30, 28 kg) of the PSo and PMo groups, respectively. Age of the ewes and the diet treatments had no significant effects (P>0·05) on feed intake, conception weight, litter size, lamb birth weight, gestation period, postpartum anoestrous period, lambing interval, sex ratio of offspring as well as conception, fertility, abortion and lambing proportions. Primiparous ewes (P) had significantly (P<0·05) higher pre-weaning lamb mortality proportion, whereas the sorghum-based diet groups had higher (P<0·05) gestation body gain and lambing weights.It was concluded that Nilotic ewes, compared with the other African sheep breeds reviewed, reach sexual maturity at an earlier age and are highly prolific due to their short postpartum anoestrous period. The results also highlight the importance of molasses and urea as efficient and good substitutes for sorghum grains and oil cakes, respectively, in the diets of ewes.

Vital statistics for an experimental flock of Merino sheep. II. The influence of age on reproductive performance

1965 ◽  
Vol 16 (4) ◽  
pp. 699 ◽  
Author(s):  
HN Turner ◽  
CHS Dolling
Keyword(s):  
Survival Rate ◽  
Reproductive Performance ◽  
Vital Statistics ◽  
Multiple Births ◽  
Reproduction Rate ◽  
Relative Importance ◽  
Merino Sheep ◽  
Age Structures

Estimates are given for various characteristics associated with reproduction rate, at each age of ewe from 2 to 10 years. In general, reproduction rate rose with increasing age to a peak, with a subsequent fall, the 10-year-old figure, however, being in most cases above the 2-year-old one. The peak occurred at 5–6 years for number of ewes lambing per ewe joined, at 6 years for survival rate of both single and twin lambs and for number of lambs weaned per ewe joined, at 7 years for number of lambs born per ewe joined, and at 7–8 years for number of multiple births per ewe joined. The estimates are used to predict the reproduction rate of flocks with different age structures, the conclusion being that the average number of lambs weaned per ewe joined would increase with the age of the oldest group of ewes even up to 8–9 years. Data from other sources are summarized for comparison. If survival rate can be improved, particularly for lambs from multiple births, then the older ewes will show an even greater advantage. Formulae are given which enable various criteria for reproduction rate, such as lambs weaned per ewe joined, to be broken into components whose relative importance can be assessed.

scholarly journals Reproductive Performance, Retention Rate, and Age at the Third Parity According to Growth Rate and Age at First Mating in the Gilts with a Modern Genotype

2017 ◽  
Vol 45 (1) ◽  
pp. 6
Author(s):  
Jamil Elias Ghiggi Faccin ◽  
Fernanda Laskoski ◽  
Paulo Emílio Lesskiu ◽  
Aline Fernanda Lopes Paschoal ◽  
André Luiz Mallmann ◽  
...  
Keyword(s):  
Growth Rate ◽  
Reproductive Performance ◽  
Retention Rate ◽  
Age And Growth ◽  
Experimental Unit ◽  
Large White ◽  
The Third ◽  
Breeding Herd ◽  
Farrowing Rate ◽  
Effect Of Age

Background: Gilts represent the largest category (18-20%) of female pigs in a breeding herd. Under field conditions, the amplitude of growth rate and age at the first mating of gilts are remarkably higher than the recommendations made by the genetic companies. There are several studies that have considered the management of these animals starting from their introduction to the herd till the mating. It has been noted that the genetic selection constantly promotes evolution that may change certain traits of these animals. However, there is a lack of the studies that evaluate the management strategies suitable for the modern sows. This study, therefore, aimed to evaluate the effect of age and growth rate of gilts at the first mating on productive performance and retention rate until the third farrowing.Materials, Methods & Results: The study was performed in a gilt development unit (GDU) with a breeding stock capacity of 1000 females and a goal of 90 gilts mating per week. The groups were retrospectively created according to age (<210 d and ≥210 d) and the growth rate (GR; <700 g/d and ≥700 g/d) at the first mating with a 2 × 2 factorial design. A real-time ultrasound examination was performed at approximately 28 days after artificial insemination to detect pregnancy. Afterward, the productivity data over three parities of 703 females were collected and analyzed at 28 commercial farms of destination. The analyses were performed using SAS, with individual gilts as the experimental unit. The total number of piglets born and the age at the third parity were analyzed using the PROC MIXED. The number of estrus at breeding, weaning-to-estrus interval and the number of piglets in the previous farrowing were included as covariates in the model of total piglets born. The farrowing rate and retention rate until the third parity were considered as binary responses and analyzed using logistic regression (PROC GLIMMIX). The effects of age, GR, and their interaction were included as fixed effect in all analyses. There was no effect of age and GR and their interaction (P > 0.05) on farrowing rate after first, second, and third mating. The total number of piglets born in the three first farrowing and over three parities were not affected (P > 0.05) by the age and GR at first mating. The retention rate until the third farrowing of gilts inseminated with more than 210 days of age was approximately 7% greater than in the gilts mated younger; however, no statistical difference (P > 0.05) was detected. An effect of the age at the first mating was observed in the age to reach the third farrowing. Gilts mated with less than 210 and more than 210 days reached the third farrowing, respectively, at 604.5 ±1.9 and 625.1 ± 2.7 days of age (P < 0.001).Discussion: With a minimum GR of 550 g/d, 180 days of age, and at least 130 kg of weight, gilts are eligible to be inseminated without impairing their litter size, farrowing, and retention rate until the third parity. The gilts having modern genotypes can have a high stillbirth rate if bred with an excessive body weight. It is worth to consider that the gilts inseminated with > 700g/d did not present overweight in this study. The reproductive performance expressed by farrowing rate and piglets born and the longevity expressed by the retention rate from the first pregnancy until the third parturition were not impaired by the groups of age and GR in Large White × Landrace crossbred (Camborough 23®). In addition, gilts inseminated earlier than 210 days but having the minimum required weight resulted in less non-productive days for the breeding herd, which represents an important financial rate to the system.

Genetic improvement of meat sheep. 4. Effect of age of dam on productivity of Dorset and Border Leicester sheep

1977 ◽  
Vol 17 (88) ◽  
pp. 735 ◽  
Author(s):  
IP Gregory ◽  
EM Roberts ◽  
JW James
Keyword(s):  
Genetic Improvement ◽  
Weaning Weight ◽  
Maximum Productivity ◽  
Clear Association ◽  
Meat Sheep ◽  
Effect Of Age ◽  
Age Structures

The effect of age of the dam on the number of lambs born (LBL) and weaned (LwL) and the weight of lambs weaned (WLWL) per ewe lambing and on the number of lambs weaned per lamb born (LwB) and lamb weaning weight (WWT) has been estimated for Dorset and Border Leicester sheep. In both breeds, LBL, LWL and WLWL showed a clear association with age of the dam, rising to a peak at a dam age of five years in the Dorsets and at between four and six years in the Border Leicester. The association between age of dam and WWT and LWB was less marked. WWT rose to a peak in both breeds at a dam age of five years and LWB rose to a peak at four and three years in the Dorsets and Border Leicester respectively. The estimates of ewe productivity were used to calculate the productivity of Dorset flocks of differing age structures. It was found that maximum productivity would be achieved with a flock aged from two to six years.

scholarly journals Effect of age at photostimulation on sexual maturity and reproductive performance in rooster breeders

2021 ◽  
Author(s):  
Lei Shi ◽  
Yunlei Li ◽  
Jingwei Yuan ◽  
Hui Ma ◽  
Panlin Wang ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Sexual Maturity ◽  
Effect Of Age
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