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 ...

A resource population of ewes derived from Dorset and Romanov grandparents was generated over 5 yr to provide genotypic and phenotypic data to estimate effects of each callipyge genotype on component traits of reproduction. Effects on ovulation rate were estimated from data recorded by examination of ovaries from serially slaughtered ewe lambs (n = 174) born in 1994 and 1995. Productivity and l...

Reproductive performance of four, five and six-year old crossbred ewes representing six combinations ofFinnsheep (F), Dorset (D), Rambouillet (R), and White Face Western (WFW) breeding were evaluated when lambing in the winter (February-March, 1977) and in the fall (October-November, 1977). The six breed combinations represented were 3fsF, 5fsWFW; %F, 1f2D, %R; %F, %D, 1f2R; %F, %R; 1f2D, 1f2R;...

A large sheep dataset including ewe and progeny records from 1982 through to 2006 was used in the present study. The data included the variables: sex of lamb, birth rank, weaning weight, year born and dam and sire. The aim was to firstly, determine if the age of the ewe’s dam, or the birth rank of the ewe affected her lifetime performance and secondly, to determine in twin-born lambs if the sex...

Although a number of common reproductive disorders in livestock involve bacterial infection, very little is known about their normal vaginal microbiota. Therefore, we sought to determine the species composition of sheep and cattle vaginal microbiota. Twenty Rambouillet ewes and twenty crossbred cows varying in age and reproductive status were sampled by ectocervicovaginal lavage. We amplified a...

Photoperiod is the proximate cue which times the reproductive period of the sheep and the role of daylength as a "zeitgeber" is evaluated in this report. Although sheep are regarded as a short-day breeding species, the reproductive period of the Suffolk ewe begins on daylengths which are on average 2.5 hours longer than those on which it ends. The reasons for this apparent anomaly are considere...

The influence of body weight at breeding on reproductive response to one and two artificial inseminations (AI) of fresh extended semen was assessed in 195 crossbred ewe lambs selected for early breeding and compared with 159 adult ewes, all housed indoors in a controlled environment. In six trials, ewe lambs and adult ewes in progestogen-induced estrus were inseminated 55 to 57 h after sponge r...

published data on the effects of ruminal bolus on the number of ovulatory follicles in ewes does not exist. the present study determined the effects of a ruminal bolus on trace element status, follicular dynamics and reproductive performance in ewes. eighty afshari cycling ewes were synchronized during breeding season using cidr for 14 days and assigned to 4 groups (n=20); group 1 received a si...

In this study 71 head of conceiving ewe and their progeny (91 head) from the flock of Lori-Bakhtiari sheep (360 head), in Sholi Station were randomly selected to determine the relationship between the immunoglobulin (IgG) concentration in the ewe's serum and colostrum, and lamb's serum. Ewe blood sample, colostrum of ewe and blood of the lamb was taken 2 weeks before parturition, 1 to 8 hours a...

The objective of this study was to carry out a sensitivity analysis on the impact of various production strategies and performance levels on the relative economic values (REVs) of traits in dairy sheep. A bio-economic model implemented in the program package ECOWEIGHT was used to simulate the profit function for a semi-extensive production system with the Slovak multi-purpose breed Improved Val...