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

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 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.

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.

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

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.

Effects of age and its relationship with body size on reproductive performance in Scottish Blackface ewes

1986 ◽  
Vol 43 (2) ◽  
pp. 279-283 ◽  
Author(s):  
R. G. Gunn ◽  
J. M. Doney ◽  
W. F. Smith ◽  
D. A. Sim
Keyword(s):  
Body Size ◽  
Reproductive Performance ◽  
Genetic Difference ◽  
Age Groups ◽  
Live Weight ◽  
Early Embryo ◽  
Ovulation Rate ◽  
Size Limitation ◽  
Pregnant Ewe ◽  
Effect Of Age

ABSTRACTOn a hill farm, the reproductive performance of Scottish Blackface ewes increases annually with increasing age up to 6 years and is positively related to pre-mating live weight. A group of Scottish Blackface ewe lambs was, from 5 months of age, preferentially managed over a 2-year period to accelerate the achievement of mature size, in order to study the relative importance of age and size to reproductive performance. Ovulation rate and early embryo mortality of these ewes at 31 months of age were compared with those of adult ewes of similar body size and condition at 79 months of age which had been reared conventionally in the same hill flock. Two comparisons were made, one between different age groups in the same year and the other retrospectively between different ages of the same age group. In the first comparison, the adult ewes had a slightly greater reproductive response which suggested a small effect of age per se but there was also the possibility of a genetic difference. In the second comparison, there was no difference in ovulation rate or potential lambing rate per pregnant ewe, but a trend towards greater wastage of twin-shed ova in the heavier and fatter younger ewes again suggested a small effect of age. At both ages, however, these ewes performed close to their adult genetic potential which suggested that the treatment of the young ewes was sufficient to overcome most of the limitations associated with age or size. Reproductive performance normally associated with young animals is therefore mainly an expression of their size relative to their maturity and the removal of the size limitation by higher levels of nutrition and more rapid growth can largely eliminate their poorer performance.

The effect of age of purebred large white and landrace boars at time of service on herd performance

1990 ◽  
Vol 1990 ◽  
pp. 59-59
Author(s):  
M. J. H. Francis ◽  
J. T. Mercer
Keyword(s):  
Reproductive Performance ◽  
Breeding Performance ◽  
Large White ◽  
The Past ◽  
Selection For ◽  
The Relationship ◽  
Effect Of Age

Practically, the effect of selection for growth and efficiency on breeding performance has been largely ignored in the past, despite changes in the age and weight of animals at puberty. It has been demonstrated that it is beneficial to delay service in gilts, both to improve their condition and allow them to complete more oestrous cycles prior to service. It seems likely that performance of boars might also be enhanced if they were worked later.This analysis was designed to examine the relationship between age and reproductive performance in the boar, with a view to developing guidelines for young boar management.

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