Female reproductive trait were studied in four pure breeds (the Finnsheep, Suffolk, Targhee and Minnesota 100), the F1 crosses between Finnsheep rams and females of the other three breeds and F2 and backcross ewes. Precocity of sexual development, defined as the percentage of ewe lambs lambing at 12 months of age, was measured in 709 ewe lambs in 4 years. Lambing and weaning rates were measured...

Sheep nematode control utilising refugia-based strategies have been shown to delay anthelmintic resistance, but the optimal indices to select individuals to be left untreated under extensive sheep grazing conditions are not clear. This experiment tested the hypothesis that high body condition can indicate ability of mature sheep to better cope with worms and therefore remain untreated in a targ...

A diallel cross involving three Moroccan breeds of sheep (Sardi, Beni Guil, and D'man) was analyzed by least squares procedures. A total of 456 ewes were mated to 22 rams and this resulted in 528 lambs born from 412 ewes. D'man ewes had by far the highest general performance as measured by total weight of lamb weaned, even though the average live weight per lamb was the lowest for the three bre...

This paper examines the environmental and management factors affecting lamb survival on high-performing sheep farms in New Zealand. Improved lambing percentage is the biggest contributor to higher profits on New Zealand sheep farms. Many sheep breeders have selected and bred ewes for increased fecundity over the last 4 decades. The increased proportion of ewes having triplets is of concern to f...

Merino and crossbred ewes were used to evaluate whether previously ram exposure in late winter could improve the response to further progestagen oestrus synchronization treatment in terms of luteal function and fertilization rate. We used 56 adult Merino and crossbred ewes randomly allocated in two groups, control (C; n= 27) and Male Effect (ME; n= 29), which had been isolated from rams for at ...

A 3-yr study was conducted to comprehensively evaluate Columbia, Suffolk, USMARCComposite (Composite), and Texel breeds as terminal sires in an extensive rangeland production system. The objective was to estimate breed-of-ram effects on ewe fertility, prolifi cacy, and dystocia, and sire breed effects on lamb survival and growth until weaning at approximately 132 d of age. Data were from 22 Col...

A 3-yr study was conducted to comprehensively evaluate Columbia, Suffolk, USMARC-Composite (Composite), and Texel breeds as terminal sires in an extensive rangeland production system. The objective was to estimate breed-of-ram effects on ewe fertility, prolificacy, and dystocia, and sire breed effects on lamb survival and growth until weaning at approximately 132 d of age. Data were from 22 Col...

A total of fifty multiparous ewes were selected immediately after lambing to study the relationship between udder morphology traits and milk production Najdi Naeimi (n=25/ breed) under intensive Saudi Arabia condition. Immediately lambing, lambs allowed suckle freely for 8 weeks; there weaned. During suckling period, typology, depth suspensory ligament in wear visually evaluated 3 weeks lambing...

St. Croix White hair sheep ewes lambing in July (n = 20) or November (n = 26) were used to evaluate the effect of ram exposure on uterine involution and postpartum luteal function. Ewes were exposed to an epididymectomized ram (EXPOSED) beginning on d 7 after lambing (d 0) or kept isolated from rams (CONTROL) through d 63. The width of each uterine horn was measured using transrectal ultrasonog...

Economic weights have been estimated in two breeds (Latxa and Manchega) using economic and technical data collected in 41 Latxa and 12 Manchega dairy sheep flocks. The traits considered were fertility (lambing per year), prolificacy (number of lambs), milk yield (litres) and longevity (as productive life, in years). A linear function was used, relating these traits to the different costs in the...