The purpose of this study was to examine the hypothesis that fenceline contact between beef calves and cows at weaning reduces indices of behavioral distress and associated temporary reductions in weight gain. One hundred Angus/Hereford-cross calves were randomly assigned to five treatments for 7 d in each of 3 yr to determine the effect of different weaning techniques on their behavior and subsequent growth. Treatments were 1) fenceline separation from dams on pasture (F-P), 2) total separation from dams on pasture (S-P), 3) total separation from dams in a drylot (corral) preconditioned to hay (S-D-P), 4) total separation from dams in a drylot not preconditioned to hay (S-D-NP), and 5) nonweaned controls on pasture (C-P). At the end of the 7-d postweaning period, all calves were placed on pasture in large groups. Calves were weighed weekly for 10 wk. In the days following weaning, F-P and C-P calves spent more time eating (grazing or eating hay) than S-P and S-D-NP calves (P < 0.05). The S-P calves spent more time walking (pacing) than calves in the other four treatments (P < 0.05), which did not differ. The S-P calves also spent less time lying down than CP, F-P, and S-D-P calves (P < 0.05); S-P and S-D-NP calves did not differ in lying time. The F-P calves vocalized less than S-P and S-D-NP calves (P < 0.05). In general, treatment differences were greatest during the first 3 d following weaning with d 2 (20 to 30 h after weaning) showing the greatest disparity. The F-P calves spent approximately 60% of their time within 3 m of the fence separating them from their dams during the first 2 d following weaning, whereas F-P cows spent about 40% of their time within 3 m of the fence during this period. Postweaning cumulative body weight gains of the F-P calves were greater than the gains recorded for the calves in the three totally separated treatments (which did not differ). The F-P calves gained 95% more weight than the average calf in the three totally separated treatments in the first 2 wk and were still heavier at 10 wk (21.4 vs 11.0 kg, respectively, at 2 wk and 50.0 vs 38.2 kg, respectively, at 10 wk; P < 0.05). It was concluded that providing fenceline contact between beef calves and cows for 7 d following weaning reduces behavioral indices of distress seen in the totally separated calves. In addition, fenceline contact with dams at weaning minimizes losses in weight gain in the days following separation. Totally separated calves did not compensate for these early losses in weight gain even after 10 wk.

Rams exhibiting relatively high levels of sexual performance (HP) repeat-breed the same female fewer times than low-performing (LP) rams. The objective of this study was to determine if HP and LP bulls differed in their tendency to repeat-breed individual females. Eighteen sexually experienced Angus bulls (20–60 months of age) were tested individually with 10 unrestrained, estrous females. The sexual behaviors of all cattle were recorded until the bull achieved six services (ejaculations). Bulls were tested on 2 days with at least 10 days between tests. Frequencies of recorded sexual behaviors were higher for LP than HP bulls (P<0.05), possibly because of the greater time spent in attaining six services. LP and HP bulls did not differ in the number of females serviced. LP bulls serviced the same number of individual females in both tests (4.0±0.3). However, HP bulls serviced a greater number of individual females (repeat-bred less) during Test 2 than Test 1 (4.7±0.3 and 3.0±0.3; P<0.05). There was no correlation between time to attain six services and the number of different females serviced (r=0.04), but the number of different females serviced positively correlated with age of the bull (r=0.53, P<0.05). Repeat-breeding of at least one female was observed in 33 of 36 tests (92%). Repeat-breeding at least one female twice in succession was observed in 24 of 36 tests (67%). There were 12 of 36 tests (33%) in which a female was serviced twice but not in succession. Females were serviced three times in succession in seven tests (19.4%). Sexual performance level did not influence mate preferences or the incidence of repeat-breeding during tests.

This study was designed to characterize conceptus development based on pre- and postnatal measurements of in vivo- and in vitro-derived bovine pregnancies. In vivo-produced embryos were obtained after superovulation, whereas in vitro-produced embryos were derived from established procedures for bovine IVM, IVF and IVC. Blastocysts were transferred to recipients to obtain pregnancies of single (in vivo/singleton or in vitro/singleton groups) or twin fetuses (in vitro/twins group). Ultrasonographic examinations were performed weekly, from Day 30 of gestation through term. Videotaped images were digitized, and still-frames were used for the measurement of conceptus traits. Calves and fetal membranes (FM) were examined and measured upon delivery. In vitro-produced fetuses were smaller than in vivo controls (P<0.05) during early pregnancy (Day 37 to Day 58), but in vitro/singletons presented significantly higher weights at birth than in vivo/control and in vitro/twin calves (P<0.05). From late first trimester of pregnancy (Day 72 to Day 93), placentomes surrounding in vitro-derived singleton fetuses were longer and thinner than controls (P<0.05). At term, the presence of giant cotyledons in the fetal membranes in the in vitro group was associated with a larger cotyledonary surface area in the fetal horn (P<0.05). The biphasic growth pattern seen in in vitro-produced pregnancies was characterized by conceptus growth retardation during early pregnancy, followed by changes in the development of the placental tissue. Resulting high birth weights may be a consequence of aberrant placental development due to the disruption of the placental restraint on fetal growth toward the end of pregnancy.