ENVIRONMENTAL AND GENETIC EFFECTS ON PREWEANING PERFORMANCE OF CALVES FROM FIRST-CROSS COWS. I. CALVING EASE AND PREWEANING MORTALITY

1982 ◽  
Vol 62 (1) ◽  
pp. 35-49 ◽  
Author(s):  
H. T. FREDEEN ◽  
G. M. WEISS ◽  
J. A. NEWMAN ◽  
G. W. RAHNEFELD ◽  
J. E. LAWSON
Keyword(s):  
Beef Cattle ◽  
The Other ◽  
Paired Comparisons ◽  
Calving Ease ◽  
Postnatal Mortality ◽  
Calf Mortality ◽  
Terminal Sire ◽  
The Relationship ◽  
Calving Difficulty ◽  
Sire Breed

Calving ease and calf mortality were studied for 4034 calves produced in second and later parities at two locations, Brandon and Manyberries, by contemporary populations of first-cross dams mated to four terminal sire breeds, Charolais (C), Chianina (Chi), Limousin (L) and Simmental (S). The dams represented 10 F1 crosses, the Hereford × Angus (HA) and nine crosses produced by mating C, L and S Bulls with Hereford, Angus and Shorthorn cows. Calving difficulty and mortality were higher among males (P < 0.0001) than females. Calving ease was not influenced by location, but postnatal mortality, particularly of males, was substantially less at Brandon (P < 0.0001). Differences in calving ease among terminal sire progeny groups were not significant when the four breeds were mated to HA dams, but all paired or three-way comparisons involving the Limousin indicated the highest proportion of unassisted births (P < 0.0001) and the lowest incidence of difficult births (P < 0.006) for this sire breed. Terminal sire differences in postnatal mortality were not present among progeny from the HA dams, nor were they observed in the paired comparisons involving progeny of the Chi vs. those of the other three terminal sire breeds. For this trait, however, the paired comparisons among progeny from C, S and L sires indicated a ranking of C > S > L (P < 0.04). Breed of dam's dam (Hereford, Angus, Shorthorn) had no influence of calving ease or mortality, but breed of dam's sire (C, L, S) was important with progeny from L-sired dams having the highest incidence of unassisted births (P < 0.01) and the highest incidence of postnatal mortality (P < 0.06). The proportion of unassisted births increased as the experiment progressed (P < 0.001) and may have been associated with advancing age of the dams. There was, however, a large location × year interaction for this trait (P < 0.002) with Manyberries recording substantially greater calving difficulty than Brandon during the first 3 yr. Interactions involving calf sex, year of birth, breed of terminal sire and location were identified for calving ease. Calf mortality generally increased with increasing calving difficulty but the relationship between calving ease and mortality was influenced by the degree of precalving environmental stress on the dam. Key words: Beef cattle, crossbreeding, calving ease, mortality

scholarly journals CALVING AND PREWEANING PERFORMANCE OF CROSSBRED PROGENY OF SOME FOREIGN AND DOMESTIC BEEF CATTLE BREEDS

1985 ◽  
Vol 65 (3) ◽  
pp. 583-593 ◽  
Author(s):  
J. A. NEWMAN ◽  
A. K. W. TONG ◽  
H. T. FREDEEN ◽  
G. W. RAHNEFELD
Keyword(s):  
Beef Cattle ◽  
Cattle Breed ◽  
Gestation Length ◽  
Beef Cow ◽  
Calving Ease ◽  
Postnatal Mortality ◽  
Beef Cattle Breeds ◽  
Calving Difficulty ◽  
Calving Traits ◽  
Intermediate Performance

Charolais-, Simmental- and Limousin-sired calves are compared for calving traits and preweaning growth based on observations of 3939 calves born in 48 western Canadian beef cow herds of Hereford, Angus and Shorthorn breeding during the period 1970–1972. Hereford cows produced calves with longer gestation lengths, higher birth weights, slower preweaning growth, and lower weaning weights than Angus cows. Shorthorn cows produced progeny with the shortest gestation lengths and intermediate performance in other traits. Limousin sires produced calves with the longest gestation lengths, the least calving difficulty, the lightest birth weights, the lowest birth-to-weaning mortality, and the slowest preweaning growth. Charolais-sired and Simmental-sired calves did not differ significantly in gestation length, postnatal mortality or preweaning growth rate, but Simmental-sired calves were lighter at birth and calved more easily. Breed-of-sire effects interacted with breed-of-dam effects for birth weight and with sex-of-calf effects for calving ease and most measurement traits, but these interactions did not generally involve a re-ranking of sire breeds. The economic impact of the results is briefly discussed. Key words: Beef cattle, breed effects, preweaning traits

BREED OF TERMINAL SIRE EFFECTS ON CARCASS CHARACTERISTICS OF THREE-WAY CROSS BEEF CATTLE REARED AT TWO LOCATIONS

1983 ◽  
Vol 63 (3) ◽  
pp. 523-549 ◽  
Author(s):  
G. W. RAHNEFELD ◽  
H. T. FREDEEN ◽  
G. M. WEISS ◽  
J. A. NEWMAN ◽  
J. E. LAWSON
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Degrees Of Freedom ◽  
Carcass Characteristics ◽  
Carcass Weight ◽  
Paired Comparisons ◽  
Breed Differences ◽  
Terminal Sire ◽  
Sire Breed ◽  
Carcass Cuts

Carcass characteristics of 3673 steers and heifers born over a 6-yr period (1973–1978) at Brandon, Manitoba (farm conditions) and Manyberries, Alberta (range conditions) were compared. Calves weaned at Manyberries were fed and evaluated at Lacombe. The progeny produced were out of 10 specific F1 crosses of dams mated to bulls of the Charolais (C), Simmental (S), Limousin (L) and Chianina (Chi) breeds. Dam crosses included the Hereford × Angus (HA) and crosses sired by C, S and L sires out of H, A and Shorthorn (N) dams. Terminal sire breed differences in the paired comparisons involving progeny of the Chi (the comparisons with maximum degrees of freedom) indicated that their carcass weight per day of age averaged 1.1% greater than C, 3.6% greater than S and 6.4% greater than L at both locations [Formula: see text]. Simmental progeny had significantly heavier (P = 0.0001) hide weights as a percentage of liveweight and significantly lower (P = 0.0001) dressing percentages than the progeny from C, L and Chi sires. Limousin and Chi-sired progeny had the lowest percentage of hide weight and the highest dressing percentage. Limousin progeny averaged 5.2% greater rib eye area/wt (cm2/kg) than Chi progeny P = 0.0001). Chianina progeny had the lowest proportions (percent of hot carcass weight) of long loin, rib, brisket and flank and the highest proportions of round and the combined trait of rib, round and long loin (P < 0.05). Chianina progeny had the highest percentage of lean in the rib, chuck and long loin while L-sired progeny had the highest percentage lean in the round. Chianina progeny had the highest and L progeny the lowest percentage bone in the rib, chuck, round and long loin. Limousin progeny had the highest lean:bone ratios but least percent lean per day of age at the long loin and round. At both locations significant terminal sire breed by year interactions were observed for all traits. The interactions of breed of dam by year, by sex, and by breed of sire and the interaction of year by sex were nonsignificant. Key words: Cattle, breeds, carcass, cuts, composition

Evaluation of Hereford and first-cross cows on three pasture systems. II. Growth of Hereford and Brahman sired calves out of mature cows

1994 ◽  
Vol 122 (1) ◽  
pp. 131-138 ◽  
Author(s):  
H. Hearnshaw ◽  
P. F. Arthur ◽  
P. J. Kohun ◽  
R. Barlow
Keyword(s):  
Average Daily Gain ◽  
The Other ◽  
Weaning Weight ◽  
South Wales ◽  
Medium Quality ◽  
The Mean ◽  
Main Effects ◽  
Calving Difficulty ◽  
Daily Gain ◽  
Sire Breed

SUMMARYThe preweaning growth of the progeny of mature cows grazing high, medium or low quality pasture was evaluated. The cows were 5–9 years of age at the beginning of the study and were either purebred Hereford (H x H), first-cross Brahman x Hereford (B x H), Simmental x Hereford (S x H) or Friesian x Hereford (F x H). Hereford and Brahman bulls were mated to these cows for three mating seasons commencing in 1982, at Grafton, New South Wales, Australia. Records on 634 calves born over three consecutive years were used.Most traits were subject to significant sire breed or dam breed effects or their interactions with one or more of the other main effects (pasture, year of birth of calf, cow age and sex of calf). The incidences of calving difficulty and stillbirths were exceptions. Stillbirths (mean of 3·8%) were not affected by any of the effects studied, while calving difficulty was affected only by sex of calf effect (males, 3·9%; females, 0·8%). The mean calving date of Brahman-sired calves was 11·4 days later (P < 0·05) than that of Hereford-sired calves. Differences between Brahman-sired and Hereford-sired calves for weaning weight were not significant for S x H (Brahman, 237 kg; Hereford, 232 kg) and FxH (Brahman, 238kg; Hereford, 238kg) dams. For HxH dams however, calves sired by Brahman were heavier at weaning (205 kg) than those sired by Hereford (193 kg) bulls, while for B x H dams the reverse was true (Brahman, 222 kg; Hereford, 231 kg). For calves with B x H dams average daily gain (ADG) was the same (957 g/day) for each sire breed, while for the other dam breeds, Brahman-sired calves had a higher ADG than Hereford-sired calves (862 v. 779, 1014 v. 946 and 1022 v. 950 g/day for H x H, S x H and FxH, respectively). Calves sired by Brahman bulls had > 90% eyelid pigmentation while Hereford-sired calves had 44–74%. On high quality pasture, the weaning weights and ADG of calves of F x H and S x H dams were higher than those of B x H and HxH dams. On medium quality pasture, weaning weight of calves of crossbred dams (B x H, S x H and FxH) were similar but higher than those of H x H dams. On low quality pasture, mean weaning weight of calves of B x H was higher than those of S x H and F x H dams, which in turn, were higher than that of H x H dams.

The influence of terminal sire breed on carcass composition and eating quality of crossbred lambs

1997 ◽  
Vol 64 (1) ◽  
pp. 77-86 ◽  
Author(s):  
M. Ellis ◽  
G. M. Webster ◽  
B. G. Merrell ◽  
I. Brown
Keyword(s):  
Subcutaneous Fat ◽  
Quality Characteristics ◽  
Carcass Composition ◽  
The Other ◽  
Eating Quality ◽  
Intermuscular Fat ◽  
Fat Level ◽  
Terminal Sire ◽  
Sire Breed

AbstractCarcass and eating quality characteristics of crossbred wether and female lambs sired by Charollais (C), Suffolk (S) and Texel (T) rams out of Mule ewes (Bluefaced Leicester ♂ × Scottish Blackface ♀ or Swaledale ♀J)were evaluated in a study carried out over a 3-year period in an upland flock. A total of 10 unrelated rams of each breed were used as sires. Lambs (no. = 280) were selected for slaughter at the same estimated subcutaneous fat level on four occasions within each year (i.e. at weaning in July and at approx. monthly intervals thereafter). Following slaughter, the left side of each carcass was physically dissected. A loin joint from lambs slaughtered in the 2nd and 3rd years of the study (no. = 184) was used to evaluate eating quality.Suffolk-sired lambs were heavier at slaughter (S: 42·2; C: 41·0; T: 40·7 (s.e. 0·35) kg) but had similar killing-out proportions compared with the other two breeds (S: 444; C: 450; T: 452 (s.e. 26) g/kg). Texel-sired lambs had higher lean proportion (S: 543; C: 550; T: 567 (s.e. 4·4) g/kg) and lower total carcass fat proportion (S: 240; C: 242; T: 233 (s.e. 5·3) g/kg) compared with S and C sired lambs. Bone proportion was similar for C and T lambs but was higher for S (S: 199; C: 191; T: 191 (s.e. 2·1) g/kg). Lean: bone (S: 2·75; C: 2·90; T: 2·99 (s.e. 0·037)) and lean:fat (S: 2·38; C: 2·40; T: 2·54 (s.e. 0·034)) ratios were higher for T-sired lambs. Female lambs were lighter (40·4 v. 42·2 (s.e. 0·24) kg), and had proportionately more intermuscular fat than wethers (122 v.118 (s.e. 1·3) g/kg) but the sex differences for other tissue proportions were small. Carcass weights and total carcass fat proportions increased and lean proportions decreased across the four slaughter dates. There were no effects of breed or sex on eating quality. However, samples from lambs slaughtered at weaning were judged to be more tender than those slaughtered later in the season.

CALVING EASE AND CALF MORTALITY IN FIRST-CROSS AND BACKCROSS COWS

1990 ◽  
Vol 70 (1) ◽  
pp. 45-54
Author(s):  
R. M. McKAY ◽  
G. W. RAHNEFELD ◽  
G. M. WEISS ◽  
H. T. FREDEEN ◽  
J. A. NEWMAN ◽  
...  
Keyword(s):  
Birth Weight ◽  
Beef Cattle ◽  
Key Words ◽  
Range Management ◽  
Intensive Management ◽  
Calving Ease ◽  
Extensive Range ◽  
Calf Mortality

Calving ease and calf mortality were evaluated for calves out of first-cross and backcross cows maintained under two contrasting environments. All calves were sired by Limousin bulls. The dam crosses at Brandon were HA, SN, CN, ACA, CCA, ASA, SSA, HCH, CCH, HSH, SSH, NCN, CCN, SSN, and NSN with H = Hereford, A = Angus, N = Shorthorn, C = Charolais, S = Simmental and a SSA cross was 3/4 Simmental-1/4 Angus. At Manyberries the dam crosses were HA, SN, ASA, SSA, HSH, SSH, NSN, and SSN. The calves were born between 1982 and 1986, inclusive, at Brandon, Manitoba (semi-intensive management) and Manyberries, Alberta (extensive range management). At Brandon, when calf birth weight was not a covariate, the significant dam cross contrasts for calving ease included less difficulty for SN cows than either the SSN or NSN cows, and for 3/4 A-1/4 European continental (E) cows than 1/4A–3/4E cows. When adjusted to a common calf birth weight the significant contrasts were HA cows had more difficulty than SN cows and the combination of SN and CN cows, SN cows had less difficulty than NSN cows, and 3/4A–1/4E cows had less difficulty than 1/4A–3/4E cows. At Manyberries, regardless of whether calf birth weight was excluded or included as a covariate, the SN cows had less difficulty than the SSN and the SSN cows had less difficulty than NSN cows. No significant dam cross comparisons were observed for calf mortality scores. Adjusting the calving ease scores to a constant calf birth weight did not significantly alter the magnitude of the contrasts but it did shift their probability levels. Location and sex of calf effects were not significant except for calving ease at Brandon where more difficulty was associated with male calves than female calves. Key words: Beef cattle, crossbreeding, backcrosses, calving, mortality

Genetic parameters for growth, reproductive performance, calving ease and suckling performance in beef cattle heifers

2004 ◽  
Vol 79 (1) ◽  
pp. 41-48 ◽  
Author(s):  
F. Phocast ◽  
J. Sapa
Keyword(s):  
Beef Cattle ◽  
Milk Yield ◽  
Reproductive Performance ◽  
Genetic Correlations ◽  
Sexual Precocity ◽  
Calving Ease ◽  
Cattle Breeds ◽  
Beef Cattle Breeds ◽  
Difficulty Score ◽  
Calving Difficulty

AbstractThere is considerable concern about the consequences on fitness-related traits of using narrow breeding objectives for production traits. The aim of this study was to assess the potential consequences of selection for growth in French beef cattle breeds by estimating genetic correlations between growth, reproduction, calving and suckling traits of Charolais, Limousin and Blonde d’Aquitaine heifers. Data consisted of the records collected from 1985 to 2002 in progeny test stations that were used in the genetic evaluation of 284 Charolais, 125 Limousin and 118 Blonde d’Aquitaine AI sires. Seven traits were considered simultaneously in the analysis: weights at 18 months and after calving (for measuring heifer growth), sexual precocity and fertility (for measuring heifer reproductive performance), calving difficulty score and pelvic opening (for measuring calving ease) and milk yield (for measuring the suckling ability of the primiparous cow). REML (co)variance estimates were derived using linear multitrait sire models. Estimates of heritability were in the range of values given in the literature. They were very similar in the Charolais and Blonde d’Aquitaine breeds, and rather different for reproductive and suckling performance in the Limousin breed. Estimates were about 0·35 for heifer growth traits and about 0·15 for calving difficulty score in the three breeds. In the Charolais and Blonde d’Aquitaine breeds, estimates of heritability were 0·15 for sexual precocity and 0·05 for heifer fertility. These estimates were close to zero in the Limousin breed. Heritabilities of pelvic opening and milk yield were, respectively, 0·2 and 0·6 in the Limousin breed and around 0·3 in the other two breeds. Genetic correlations between traits concerning the same ability (as, for instance, weight at 18 months and weight at calving) were high and, in general, similar among breeds. Genetic correlations between heifer growth, reproductive traits, calving ease and suckling performance were nil or slightly favourable in the three breeds. Consequently, past selection mainly directed towards increasing growth seems not to have adversely affected the efficiency of female reproduction and the maternal abilities of French specialized beef cattle breeds.

GENETIC EFFECTS ON POSTWEANING GROWTH OF THREE-WAY CROSS BEEF CATTLE

1988 ◽  
Vol 68 (3) ◽  
pp. 647-654 ◽  
Author(s):  
G. W. RAHNEFELD ◽  
G. M. WEISS ◽  
H. T. FREDEEN ◽  
J. A. NEWMAN ◽  
J. E. LAWSON
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Growth Traits ◽  
Average Daily Gain ◽  
Genetic Effects ◽  
Genetic Interactions ◽  
Cross Breeding ◽  
Terminal Sire ◽  
Daily Gain ◽  
Sire Breed

Genetic effects on postweaning growth traits were evaluated for 3592 crossbred steers and heifers fed at two locations, Brandon, Manitoba and Lacombe, Alberta during a 6-yr period (1973–1978). The calves were sired by Chianina (Chi), Charolais (C), Limousin (L) and Simmental (S) bulls mated to 10 F1 dam-crosses representing the Hereford × Angus (HA) and nine dam-cross combinations produced by mating C, S and L sires with H, A and Shorthorn (N) females. Progeny rankings by terminal sire breed for weight on-test were C = Chi = S > L. For the trait 140-d postweaning average daily gain, progeny rankings were C > Chi = S, C = Chi > L and Chi > S > L. The progeny from the majority of "exotic" cross-dams were heavier on-test, and had higher postweaning average daily gain than progeny from HA dams. Ranking of dam-crosses according to their breed of sire (DS) for the trait weight on-test were S > C > L. The DS comparisons for postweaning average daily gain were C > S > L. The ranking of dam-crosses by breed of dam's dam, for on-test weight and postweaning average daily gain were N > H = A. Genetic interactions (terminal sire by breed cross of dam) were absent. Genotype environment interactions involving breed of terminal sire with year, sex and location were found for weight on-test and postweaning average daily gain. All resulted from changes in the magnitude of breed of sire differences, not from changes in sire rankings. Key words: Cattle, breeds, cross breeding, growth

Evaluation of Angus, Charolais and Hereford as terminal sire breeds on Hereford and first-cross cows. II. Carcase characteristics and retail yield of progeny

1995 ◽  
Vol 46 (6) ◽  
pp. 1245 ◽  
Author(s):  
PF Arthur ◽  
H Hearnshaw ◽  
D Johnston ◽  
PD Stephenson
Keyword(s):  
The Other ◽  
Muscle Area ◽  
Eye Muscle ◽  
Breed Differences ◽  
Kidney Fat ◽  
Dressing Percentage ◽  
The Individual ◽  
Terminal Sire ◽  
Sire Breed

The characteristics and retail yield of carcases of 482 Angus, Charolais and Hereford sired progeny out of straightbred Hereford (HxH), and first-cross Brahman x Hereford (BxH), Simmental x Hereford (SxH) and Friesian x Hereford (FxH) dams were evaluated. The cattle had been raised and slaughtered for either the vealer (both sexes), yearling domestic (both sexes) or the heavy export steer market. The data were analysed within market type, and at a constant age at slaughter (281, 478 and 829 days for vealer, yearling domestic and heavy export carcases respectively) and also at a constant hot P8 fat depth (4.6, 7.8 and 14.9 mm for the three markets respectively) and constant hot carcase weight (160, 200 and 343 kg for the three markets respectively). At a constant age, carcases of Charolais sired progeny were significantly (P < 0.05) heavier (8-16%, depending on market type), leaner, had larger eye muscle area and higher dressing percentage than those of Angus and Hereford sired progeny. This resulted in 12 to 17% (P < 0.05) more kg of boneless saleable meat (retail yield) from carcasses of Charolais sired progeny. At a constant hot P8 fat depth, the magnitude of the sire breed differences increased, whereas at a constant hot carcase weight, the differences became non-significant or were reduced in magnitude. At a constant age, progeny of BxH dams had higher ( P < 0.05) dressing percentage than those of the other dam breeds for all market types except the vealer market. Progeny of FxH dams had more (P < 0.05) channel and kidney fat than those of the other dam breeds, even at a constant hot P8 fat depth. Retail yield, as a percentage of the boned side, was highest for carcases of progeny of BxH dams and lowest for those of progeny of FxH dams (70.2% and 70.3% v. 69.1% and 69.2%, for vealer and yearling domestic carcases respectively, at a constant age). Sire and dam breed effects for the individual primal cuts, as percentages of the boned side, were not significant for most of the primal cuts, and where significant, the differences were very small.

ENVIRONMENTAL AND GENETIC EFFECTS ON PREWEANING PERFORMANCE OF CALVES FROM FIRST-CROSS COWS. II. GROWTH TRAITS

1982 ◽  
Vol 62 (1) ◽  
pp. 51-67 ◽  
Author(s):  
H. T. FREDEEN ◽  
G. M. WEISS ◽  
J. A. NEWMAN ◽  
G. W. RAHNEFELD ◽  
J. E. LAWSON
Keyword(s):  
Growth Rate ◽  
Sex Differences ◽  
Birth Weight ◽  
Beef Cattle ◽  
Key Words ◽  
Growth Traits ◽  
Genetic Effects ◽  
Genetic Interactions ◽  
Terminal Sire ◽  
Sire Breed

Environmental and genetic effects on preweaning growth traits were evaluated for 4034 calves born and 3732 calves weaned in second and later parities from contemporary populations of first-cross dams maintained at two locations, Brandon and Manyberries. The calves were sired by Chianina (Chi), Charolais (C), Limousin (L) and Simmental (S) bulls mated to 10 F1 dam crosses representing the Hereford × Angus (HA) and nine dam-cross combinations produced by matings of C, S and L sires with H, A and Shorthorn (N) females. Sex differences were important (P < 0.0001) with males averaging 7% heavier at birth and 5% higher in measures of postweaning growth than females. Location differences were negligible for birth weight (1.2%), but preweaning growth rate was 10–13% greater at Brandon (P < 0.0001) than at Manyberries. Year differences were large for all traits measured (P < 0.0001) and, with the exception of birth weight, were related to differences in annual weaning date. Progeny rankings by terminal sire breed were Chi > C (2.5%), Chi > S (4.2%), and Chi > L (11.4%) for birth weight (all P < 0.0001) and Chi = C = S > L by 6% (P < 0.0001) for all measures of preweaning growth. Ranking of the dam crosses by their breed of sire (DS) were C > S > L for birth weight (P < 0.0001) and S > C > L for preweaning growth (P < 0.0002). The paired DS comparisons indicated S > L by 9.1% and C > L by 2.7% for growth rate. Ranking of the dam crosses by their breed of dam (DD) were H = N > A (P < 0.0001) for birth weight and [Formula: see text] for preweaning growth traits. A location × dam cross interaction was evident for the Charolais × Shorthorn dam cross (P < 0.01). Progeny from all dam crosses except the LH and LA at Manyberries grew more rapidly than their contemporary controls (HA progeny) with the Simmental crosses averaging 11–14% higher than the HA. Genetic interactions involving breed of sire and breed of dam were absent. Key words: Beef cattle, crossbreeding, preweaning growth

scholarly journals 45 Effect of terminal sire breed on grazing performance, parasitism, and market grade of crossbred lambs: year 2

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 69-70
Author(s):  
Curtis Patton ◽  
Camren l Maierle ◽  
Andrew R Weaver ◽  
Scott P Greiner ◽  
Scott A Bowdridge
Keyword(s):  
Soybean Meal ◽  
The Other ◽  
Previous Model ◽  
Project Duration ◽  
Organic Farm ◽  
Significant Difference ◽  
Carcass Conformation ◽  
Terminal Sire ◽  
Sire Breed ◽  
Cell Volumes

Abstract Improvements in growth and carcass conformation through terminal sire crossbreeding systems may improve lamb value in a pasture-based system. Therefore, the aim of this study was to replicate the previous model of this experiment and compare the effects of different terminal sires on parasitism, growth, composition and marketability of grazing lambs and lambs at weaning. Suffolk SU (n = 2) and Texel TX (n = 3) sires were mated to commercial ewes at the WVU Organic Farm. April-born lambs were managed as one group until weaning in mid-June. One group containing TX (n = 28) and SU (n = 22) was sold at weaning, the other group was sorted into 3 replicates per sire breed. Lambs were rotationally grazed for 62-d with paddock movements every 10-d. Lambs were supplemented at a rate of 2% of bodyweight with a 16% CP corn-soybean meal supplement. Weights and FAMACHA were collected at weaning and then weekly for the duration of the study. Fecal egg counts (FEC) and packed cell volumes (PCV) were collected bi-weekly. Lambs were dewormed when FAMACHA score was a 3 or greater. Ultrasound measures of rib eye area (REA) and fat depth were obtained at study conclusion and lambs were marketed at the same graded auction as the group sold at weaning. There was no significant difference in FEC and PCV data values during project duration (P = 0.32) (P = 0.19). Fewer deworming treatments were necessary in TX-sired lambs at 19% (7/36) whereas SU-sired lambs required 42% (15/36) (P = 0.04). REA and fat depth measurements were not significant between sired breeds (P = 0.21) (P = 0.50). Texel-sired lambs received a $0.26/Kg greater premium than the SU-sired lambs at weaning. Texel-sired lambs received a $0.29/Kg greater premium than the SU-sired lambs after the conclusion of grazing. These data demonstrate that Texel-sired lambs required fewer dewormer treatments and received premiums when marketed at a graded auction.

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