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Biomedical subjects

F S McClaugherty

Publications and source records attributed to F S McClaugherty.

8 recordsLinked to original sources
PubMed1991

Effects of ewe breed and management system on efficiency of lamb production: I. Ewe productivity.

Performance of 1/2-Suffolk, 1/2-Rambouillet (Western) and 1/2-Suffolk, 1/4-Rambouillet, 1/4-Finnsheep (1/4-Finn) ewes was compared in three different lamb production systems over 3 yr. System 1 (56 ewes) involved late fall lambing over 84 d. System 2 (51 ewes) involved January and February lambing for 60 d. System 3 (47 ewes) involved March and April lambing for 45 d. Pregnancy rates for yearling ewes were lower in System 1 in yr 1 (50.7% vs 87.4% for Systems 2 and 3) but differed little among systems for older ewes or in remaining years. Average pregnancy rates for 2-yr-old and older ewes were 89.5, 94.0 and 85.7% for Systems 1, 2 and 3, respectively. When the pregnancy rate was adjusted to a 45-d lambing season, means for older ewes were 78.6, 89.5 and 85.7% for System 1, 2 and 3, respectively. Ewe breeds did not differ in their pregnancy rates. Prolificacy (lambs born per ewe lambing) was higher for 1/4-Finn ewes (1.83 +/- .06 vs 1.55 +/- .07) and was higher in System 3 (1.86 +/- .06) than in Systems 1 (1.60 +/- .07) or 2 (1.63 +/- .05). Body weight at breeding in postyearling ewes was less in System 3 (64.3 kg); than in Systems 1 or 2 (average of 73.1 kg). Breeds did not differ in weight at 1 or 2 yr of age, but Western ewes were 2.1 +/- 1.1 kg heavier as 3-yr-olds.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Husbandry↗
PubMed1991

Effects of ewe breed and management system on efficiency of lamb production: II. Lamb growth, survival and carcass characteristics.

Lamb growth, survival and carcass characteristics were compared for progeny of either 1/2-Suffolk, 1/2-Rambouillet (Western) ewes or 1/2-Suffolk, 1/4-Rambouillet, 1/4-Finnsheep (1/4-Finn) ewes produced over 3 yr in three different management systems. System 1 lambs were born in late fall and fed to slaughter on a concentrate diet. System 2 lambs were born in January and February and grazed pure stands of alfalfa or ladino clover after weaning. System 3 lambs were born in March and April and remained with their dams on native bluegrass-white clover pasture throughout the grazing season. Lambs were slaughtered as males reached 55 kg and as females reached 50 kg. One-half of the males in System 1 were left intact; all males in Systems 2 and 3 were castrated. Lamb survival did not differ among systems. Lambs from yearling 1/4-Finn ewes had higher survival rates than lambs from yearling Western ewes, but at older ewe ages, progeny of the ewe groups did not differ in survival. Lambs in System 1 grew fastest (mean lifetime gains of 310 +/- 4 g/d) and were youngest at slaughter (156 +/- 3 d), and lambs in System 3 were oldest at slaughter (234 +/- 2 d). System 2 lambs differed considerably among years in growth rate and slaughter age (mean slaughter ages of 191, 230 and 193 d across years), primarily in response to differences in rainfall. Lifetime gains and slaughter ages of lambs did not differ between ewe breeds. Ram lambs grew 15% faster than wethers and were leaner. Differences among systems in carcass traits were small. System 1 lambs tended to be fattest and System 2 lambs leanest. Progeny of 1/4-Finn ewes had higher subjective scores for carcass fatness (e.g., feathering, flank fatness) and conformation but did not differ from progeny of Western ewes in objective measures of fatness (e.g., backfat, yield grade).

Animal Feed↗
PubMed1985

Breed group differences in testicular growth patterns in spring-born ram lambs.

Three groups of spring-born ram lambs were used to assess breed group differences in testicular growth patterns through 5 mo of age. Group 1 included 20 3/4-Finnish Landrace (Finn), 1/4-Rambouillet rams and 31 1/8-Finn, 7/8-Rambouillet rams. Group 2 included 23 3/4-Finn, 1/4-Dorset rams and 19 1/8-Finn, 7/8-Dorset rams. Group 3 included 21 black-faced (BF) rams (six Hampshire and 15 Suffolk) and 46 whitefaced (WF) rams (nine Dorset, 20 Barbados Blackbelly X Dorset, 10 Finn X Dorset and six Dorset X Finn). Scrotal circumference (C) was measured at 19, 43, 72, 100, 128 and 153 d in Group 1; at 20, 48, 76, 93 and 153 d in Group 2 and at 40, 60, 81, 103, 124 and 158 d in Group 3. Breed group X age interaction was tested to assess breed group differences in testicular growth patterns, and logistic curves were used to describe increases in scrotal circumference with age. In Group 1, 3/4-Finn and 1/8-Finn rams were similar in estimated final scrotal circumference at 150 d of age (260 and 259 mm, respectively), but rapid testicular growth began earlier in 3/4-Finn rams. The estimated age at which the growth rate in scrotal circumference was maximum was 81 d for 3/4-Finn rams and 93 d for 1/8-Finn rams. No differences were observed in testicular growth in Group 2 rams. However, in Group 3, smaller WF rams matured more rapidly than larger BF rams. Growth in scrotal circumference was most rapid at 99 d in BF rams and 88 d in WF rams. Within WF rams, Barbados Blackbelly X Dorset and Finn X Dorset rams matured earlier than Dorsets. In all groups, the primary breed difference was associated with age differences during the period of rapid testicular growth.

Age Factors↗
PubMed1984

A comparison of Dorset and Finnish Landrace crossbred ewes.

Data from 644 exposures and 552 lambings were used to analyze reproductive traits of 1/2-Finnish Landrace, 1/2-Dorset ewes (1/2 Finn); 1/4-Finnish Landrace, 3/4-Dorset ewes, (1/4 Finn) and Dorset ewes. Ewes were exposed to Hampshire or Suffolk rams for spring lambing from 1973 to 1978. The analytical model included fixed effects of ewe birth year (EBY), ewe breed (BR), lambing year within EBY and EBY X BR interaction and random effects of ewe within EBY and BR. Conception rate differed (P less than .01) for 1/2-Finn (.94), 1/4-Finn (.88) and Dorset (.80) ewes. Litter size was highest (P less than .01) for 1/2-Finns (1.97), followed by 1/4-Finns (1.74) and Dorsets (1.44). The 1/2-Finn ewes ranked first for number and weight of lambs weaned, and for number and weight marketed as feeder lambs. Birth weights were heavier (P less than .001) for lambs with Dorset dams (3.88 kg) than for lambs with 1/4-Finn (3.24 kg) or 1/2-Finn (3.08 kg) dams. Preweaning average daily gains and adjusted 90-d weights were also larger (P less than .001) for lambs with Dorset dams (.26 kg/d and 28.3 kg, respectively) than for lambs with 1/4-Finn (.24 kg/d and 25.4 kg) or 1/2-Finn (.24 kg/d and 25.1 kg) dams. However, Dorset ewes lambed an average of 10.5 d later than Finn-cross ewes, and actual weaning weights (unadjusted for age) did not differ significantly among lambs from Dorset (27.2 kg), 1/4-Finn (26.9 kg) and 1/2-Finn ewes (26.7 kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Breed differences in testicular growth and gonadotropin secretion in prepubertal ram lambs.

Scrotal circumference (SC) and plasma concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured in 19 Finnish Landrace (Finn) and 29 Rambouillet crossbred ram lambs raised in confinement and in 21 Finn and 19 Dorset crossbred ram lambs raised on pasture. SC was larger (P<0.05) for Finn crossbreds than for Rambouillet crossbreds only at 70 and 100 days of age. Finn crossbreds had more (P<0.05) plasma LH and FSH than did Rambouillet crossbreds at 20 and 44 days but not at 70 days. SC was larger for Dorset crossbreds than for Finn crossbreds at the same age, but SC was larger (P<0.05) for Finn crossbreds than for Dorset crossbreds at the same weight. Finn and Dorset crossbreds differed (P<0.10) in plasma LH and FSH concentration at 77 days only (Finn>Dorset).

Journal Article↗
PubMed1981

Accuracy of estimation of testis weight from in situ testis measures in ram lambs.

At a mean age of 93 +/- 5 days and a mean weight of 29 +/- 5 kg, 44 crossbred ram lambs were castrated to evaluate the accuracy of the estimation of testis weight from in situ testis measures (scrotal circumference and testis diameter). Means and standard deviations for testis weight (both testes), scrotal circumference and average in situ testis diameter were 134 +/- 57 g, 20.2 +/- 3.1 cm and 3.7 +/- .7 cm, respectively. Testis weight (W) was predicted from scrotal circumference (C) and average in situ diameter (D(o)) as W=.131C(1.90) D(o)(.88) (R(2)=.949). When adjusted to the same scrotal circumference and in situ diameter, testes of 3/4-Finnish Landrace rams were heavier (P<.05) than testes of 7/8-Dorset rams. However, the additional accuracy obtained by using equations specific to each crossbred group was small.

Journal Article↗