the aim of this study was to determine the effect of ewe breed on the reaction time and semencharacteristics in the ram. for this purpose, from the native sheep breeds in iran, seven lory rams and fourewes (two lory and two ghezel breeds) were selected. seven rams were individually subjected to 4 weeklytrials in which one of the following two treatments was applied alternately. all of rams were...

Objectives were to estimate effects of sire breed (Dorset, Finnsheep, Romanov, Texel, and Montadale), dam breed [Composite III (CIII) and northwestern whiteface (WF)], mating season (March and May), and their interactions on reproductive traits of mature F1 ewes in spring mating seasons. A total of 1,099 F1 ewes produced 1,754 litters of 2,995 lambs from exposures to Suffolk rams during March a...

Ability to select service sires that minimize partial or complete losses of pregnancy could have major economic impacts in sheep production systems. This study tested the null hypothesis that survival of potential progeny did not vary with breed type of service sire or among individual rams. Data included 980 ewes on 10 farms; each ewe was pregnant to 1 of 67 rams of 12 breeds. Number of concep...

Effects of breed and sward surface height on ewe liveweight and body condition changes and on lamb liveweight gains during grazing in the spring and autumn were studied. The output per hectare in each season was also calculated. A total of 112 Gallega ewes (35Æ6 kg live weight) and 204 Latxa ewes (47Æ5 kg live weight) with their lambs were used during the spring (March–June) to study the effect...

The number of lambs sold per ewe mated in the breeding flock has a considerable impact on sheep operation profitability. This depends primarily on fertility, prolificacy (# of lambs), and lamb survival, mothering ability, milk production of the ewe and lamb growth rate. Optimal reproduction does vary by environment and management system – some sheep operations don’t want a lambing rate over 200...

Three experiments were conducted, using 1,488 ewes during seasonal anestrous and during the normal estrous period, to evaluate the influence of breed on response to exogenous hormones. Treatment was intravaginal, progestogen pessaries Days 1 to 16, 10 mg crystalline progesterone on Day 16, followed by 750 IU PMS on Day 17. In the anestrous ewes a second PMS injection was given on Day 32 in one ...

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...

The number of lambs sold per ewe mated in the breeding flock has a considerable impact on sheep operation profitability. This depends primarily on fertility, prolificacy (# of lambs), and lamb survival, mothering ability, milk production of the ewe and lamb growth rate. Optimal reproduction does vary by environment and management system – some sheep operations don’t want a lambing rate over 200...

Ewe productivity is synonymous with annual litter-weight weaned (LWW) per ewe exposed to rams for breeding, and LWW is largely a function of number of lambs born (NLB) and weaned (NLW). Selecting for LWW should increase litter size and numbers of ewe-ram co-twins. Thus, we used historical records to determine whether sex of co-twin affected lifetime productivity of twinborn ewes. United States ...