THE OBJECTIVE OF THIS STUDY WAS TO COMPARE THE GOODNESS OF FIT OF FOUR LACTATION CURVE MODELS: Wood's Gamma model (WD), Wilmink (WL), and Pollott's multiplicative two (POL2) and three parameters (POL3) and to determine the environmental factors affecting the complete lactation curve of F1 dairy sheep under organic management. A total of 5,382 weekly milk yields records from 150 ewes, under orga...

Two-hundred-fifty-six crossbred and Targhee ewes which lambed in February and March were randomly assigned to a 38or 73-day postpartum weaning group and within weaning group to a control, an 8or a 16-day progestogen treatment. Treatment was an intravaginal progestogen pessary for 7 days after weaning or for 15 days beginning 8 days before weaning with a 10 mg injection of progesterone on the da...

BACKGROUND The effect of different thawing procedures for ram semen frozen in minitubes and mini straws on the fertility of sheep was tested in a field trial. METHODS Altogether, 719 Norwegian Crossbred ewes, aged between six months and six-and-a-half years from 8 farms, were inseminated vaginally in natural oestrus with frozen-thawed semen. Minitubes were thawed at 70 degrees C for 8 sec (T7...

Reproductive performance and body weights of four and five-year old crossbred ewes representing five combinations of Finnsheep (F), Dorset (D) and Rambouillet (R) breeding were evaluated when lambing in the summer Oune-July, 1976). The five breed combinations represented were 1f2D, 1f2R; %D, %R; %F, 1f2D, %R; %F, %D, 1f2Rand %F, 3f4R. Breeding effectiveness of purebred and crossbred rams of Ham...

Selection for fertility in a fall lambing system was applied for 5 yr (1.45 generations) in a crossbred sheep population. Three flocks were involved: a fall-lambing selected (S) flock of 125 ewes and 10 rams, a fall-lambing environmental control (EC) flock of 55 ewes and five rams, and a spring-lambing genetic control flock of 45 ewes and five rams used to produce replacements for EC. Estimated...

using melatoninin ewes of iran black breed, this study aimed to compare the reproduction and production performances in lambing program of two and three times per years for duration of two years. a hundred ewes allocated to two parallel groups: group a (ewes in three lambing managing system using melatonin) and group b (ewes in two lambing managing system without using melatonin). to induce the...

The aim of the research was to evaluate the influence of sex, breeding group, litter size and age of lambs when placed in lambing pens for their growth rate during rearing. The average daily gain of lambs was evaluated based on their weighing data each week after their placement into lambing pens. Lambs of Improved Valachian, Tsigai and Lacaune breed (n=26) had been gradually integrated to the ...

a number of 5558 lambing records of 2245 mehraban ewes, collected during years 1995 to 2010 were utilized to estimate the variance components and heritability for the number of lambs per lambing,  making use of b-spline random regression models. the fixed factors affecting the studied trait were identified using general linear model analysis as well as sas software, where flock-year-season and ...

BACKGROUND Artificial insemination (AI) can serve as a powerful tool to the sheep owners for making rapid genetic progress of their flock. The AI in sheep is mostly performed using fresh semen with two reasons i) lambing rate following trans-cervical AI with frozen semen is limited by the inability of frozen-thawed sperm to transit the cervix and ii) the need of circumventing the cervical barri...

The difficulty of cervical penetration severely limits the use of transcervical AI (TAI) in sheep, and trauma from cervical manipulation (CM) may reduce fertility after TAI. We investigated the effects of cervical dilation using exogenous oxytocin (OT) to facilitate TAI and its effects on reproductive variables after laparoscopic AI (LAI). Estrus was synchronized by inserting pessaries impregna...