scholarly journals Impact of slick hair trait on physiological and reproductive performance in beef heifers consuming ergot alkaloids from endophyte-infected tall fescue1

2019 ◽  
Vol 97 (4) ◽  
pp. 1456-1467 ◽  
Author(s):  
Rebecca K Poole ◽  
Thomas L Devine ◽  
Kyle J Mayberry ◽  
Joan H Eisemann ◽  
Matt H Poore ◽  
...  
Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 849
Author(s):  
Aitor Fernandez-Novo ◽  
Sergio Santos-Lopez ◽  
Jose Luis Pesantez-Pacheco ◽  
Natividad Pérez-Villalobos ◽  
Ana Heras-Molina ◽  
...  

In beef herds, increasing animal welfare, improving reproductive performance and easing animal management are key goals in farm economics. We explored whether delaying the removal of the intravaginal progesterone device by 24 h in heifers synchronized with a 5d Co-synch 72-h protocol could improve reproductive efficiency of fixed-time artificial insemination (FTAI). In experiment 1, we examined the total synchronization rate (TSR) in cycling Holstein heifers. Heifers (13.4 ± 0.69 mo.) were randomly assigned to the standard 5d Co-synch 56-h protocol (5dCo56; n = 10), 5d Co-synch 72-h (5dCo72; n = 17), or the modified 5d Co-synch 72-h protocol, in which removal of the progesterone device was delayed by 24 h (6dCo48; n = 19). In experiment 2, 309 cycling beef heifers on 18 commercial farms were subjected to the 5d Co-synch 72-h or 6-d Co-synch 48-h protocol and conception rate (CR) studied. In experiment 1, the three protocols led no differences on TSRs of 80.0% (5dCo56), 88.2% (5dCo72), and 89.5% (6dCo48). In experiment 2, the CR from the beef heifers, observed during two consecutive reproductive seasons did not differ: 59.7% for 5dCo72 and 62.0% for 6dCo48 (p = 0.907). Therefore, delaying removal by 24 h provides satisfactory results without reducing reproductive efficiency of heifers.


2017 ◽  
Vol 5 (2) ◽  
pp. 26
Author(s):  
Janice G. P. Bowman ◽  
Bok F. Sowell

One hundred-one crossbred beef heifers (average weight 256.1 kg) were used to evaluate the effects of diet during an 84-day period, on growth and reproductive performance. The four treatments were: 1) grass hay; 2) grass hay + 0.9 kg/day barley; 3) grass hay + 1.8 kg/day barley; and 4) alfalfa hay. Heifers were assigned randomly to 12 pens by weight (three pens/treatment). Prior to feeding, barley was cracked through a roller-mill. Heifers consuming alfalfa hay or grass hay + 1.8 kg barley gained 39% faster (0.68 and 0.74 kg/day, respectively; P = 0.01) than heifers consuming grass hay alone (0.51 kg/day). Heifers consuming grass hay + 0.9 kg barley were intermediate in average daily gain (ADG; 0.63 kg/day). Hay intake was 16% greater (P < 0.10) by heifers consuming alfalfa hay, grass hay, and grass hay + 0.9 kg barley compared with those consuming grass hay + 1.8 kg barley (average 8.1 vs 7.0 kg/day). Using costs (USD) of $0.066/kg, $0.099/kg, and $0.0935/kg for grass hay, alfalfa hay, and barley, respectively, feed cost/day was greatest (P < 0.01) for alfalfa hay ($0.81/day), intermediate for the grass hay + barley diets (average $0.63/day), and lowest for grass hay ($0.53/day). Cost/kg gain was less (P < 0.10) for grass hay + 1.8 kg barley compared with alfalfa hay. No diet differences (P > 0.70) were found in reproductive performance of the heifers. Feeding replacement heifers alfalfa hay resulted in performance equivalent to feeding grass hay + 1.8 kg barley, but the alfalfa hay diet had a higher cost.


1995 ◽  
Vol 44 (2) ◽  
pp. 189-197 ◽  
Author(s):  
R.L. Larson ◽  
L.R. Corah ◽  
M.F. Spire ◽  
R.C. Cochran

2018 ◽  
Vol 96 (suppl_2) ◽  
pp. 201-201
Author(s):  
S A Springman ◽  
T L Meyer ◽  
M E Drewnoski ◽  
R N Funston

1994 ◽  
Vol 74 (1) ◽  
pp. 73-76 ◽  
Author(s):  
B. D. King ◽  
R. N. Kirkwood ◽  
C. L. Guenther ◽  
R. D. H. Cohen ◽  
G. A. Bo ◽  
...  

Live weight, average daily gain (ADG) and reproductive performance were compared between heifers implanted with zeranol at birth, 100 and 200 d of age (n = 54) and those not implanted (n = 50). Zeranol implantation resulted in increased (P < 0.05) ADG from birth to weaning, weaning weight, ADG from weaning to breeding, breeding weight and calving weight but did not affect (P > 0.05) calf birth weights, incidence of dystocia, calf survival or gestation lengths. Zeranol implants did not affect (P > 0.05) the incidence or magnitude of the pre-ovulatory LH surge or the number of heifers that ovulated between 48 and 168 h after cloprostenol injection. Pregnancy rate 42 d after bull entry did not differ between the two groups (P > 0.10), tended toward a difference at 72 d (P < 0.10), and was different at 133 d (P < 0.05), with implanted heifers having a lower pregnancy rate than non-implanted heifers. Between day 72 and day 133 after bull entry there was a 10% embryonic or fetal mortality rate in zeranol-implanted heifers, which differed from the 0% loss in non-implanted heifers (P < 0.05). We conclude that serial implants of zeranol from birth reduced the pregnancy rate in heifers and that this effect was due to early fetal loss. Key words: Zeranol, embryonic/fetal mortality, bovine, pregnancy rate, ultrasonography


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