scholarly journals LIFETIME REPRODUCTIVE EFFICIENCY OF FIRST-CROSS BEEF COWS UNDER CONTRASTING ENVIRONMENTS

1981 ◽  
Vol 61 (3) ◽  
pp. 539-554 ◽  
Author(s):  
H. T. FREDEEN ◽  
G. M. WEISS ◽  
J. A. NEWMAN ◽  
J. E. LAWSON ◽  
G. W. RAHNEFELD
Keyword(s):  
Environmental Stress ◽  
Data Base ◽  
Reproductive Performance ◽  
Beef Cows ◽  
Performance Criteria ◽  
Reproductive Efficiency ◽  
Pasture Management ◽  
Mating Opportunities ◽  
Sire Breed ◽  
Slight Advantage

A population of 1150 first-cross females representing the Hereford-Angus (control) and nine crosses produced by mating bulls of the Charolais (C), Simmental (S), and Limousin (L) breeds with cows of Hereford (H), Angus (A) and Shorthorn (N) breeding provided the data base for breed-cross comparisons of lifetime reproductive performance under two contrasting environments. These data comprised 6022 mating opportunities and 5053 pregnancies recorded during a period that commenced with the breeding season of 1971 and terminated at weaning in the fall of 1979.There were substantial location differences in all performance criteria with the relatively stringent range environment (Manyberries, Alberta) resulting in greater cow losses, lower conception and weaning rates, and less weight of calf weaned than occurred under semi-intensive pasture management (Brandon, Manitoba). Barren culls comprised the largest proportion of cow losses with sire breed ranking C < S < L and dam breed ranking A < H < N for the exotic crosses at both locations. The C cross also ranked lowest for total attrition and highest for percentage conception and percentage of calves weaned per mating opportunity at each location. At Manyberries, these elements of performance combined to give C cross dams a slight advantage in weight of calf weaned per mating opportunity (143 vs. 139 kg for S cross dams), but this ranking was reversed at Brandon (176 vs. 181 kg for S cross). First-cross dams out of A cows at Manyberries ranked above the N cross in weight of calf weaned (139 vs. 135 kg), but this position was reversed at Brandon (172 vs. 176 kg). These changes in ranking at the two locations (C vs. S and A vs. N) may have reflected differences in the degree of environmental stress imposed by the lactation process. All of the sire breed (C, S, L) and dam breed (H, A, N) combinations ranked above the HA control for weight of calf weaned per mating opportunity. However, for this measure of productivity the L vs. HA difference at Manyberries (125 vs. 124 kg) was negligible.

Reproductive efficiency of F1 and reciprocal backcross beef cows under contrasting environments

1991 ◽  
Vol 71 (4) ◽  
pp. 969-985 ◽  
Author(s):  
G. W. Rahnefeld ◽  
R. M. McKay ◽  
G. M. Weiss ◽  
H. T. Fredeen ◽  
J. A. Newman ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Beef Cows ◽  
Performance Criteria ◽  
Reproductive Efficiency ◽  
Mating Opportunities ◽  
The Difference ◽  
Reciprocal Backcross

A population of 860 F1 and reciprocal backcross females representing Hereford (H), Angus (A), Shorthorn (N), Charolais (C) and Simmental (S) breeding were evaluated for reproductive efficiency under two contrasting environments (Brandon, Manitoba and Manyberries, Alberta). The F1 included the HA, CN and SN and the reciprocal back-crosses were HCH, CCH, ACA, CCA, HSH, SSH, ASA, SSA, NSN, SSN, NCN and CCN. All females were bred to Limousin bulls. The data collected from 1980 to 1986 comprised 3108 mating opportunities and 2523 pregnancies. For dam crosses common to both locations (HA, SN and specific dam crosses involving S) differences in performance criteria occurred with females at Manyberries recording greater cow losses, higher conception and weaning rates, and more weight of calf weaned than at Brandon. Combining these performance elements gave the females at Manyberries an advantage for weight of calf weaned per mating opportunity (162 ± 3.2 vs. 152 ± 3.0 kg). Barren culls comprised the largest proportion of cow losses at both locations with HA and NSN greatest and ASA lowest at Brandon, and SSH greatest and SN lowest at Manyberries, all significant at P ≤ 0.05. None of the differences for C cross females was significant (P > 0.05). Weaning rates per mating opportunity for dam crosses common to both locations indicated the ASA highest and the SSH lowest at both locations, the difference being 22.9% at Brandon and 13.2% at Manyberries. For the HA, CN and C backcross comparisons, the highest weaning rate per mating opportunity was recorded for the HA (73.3%) and the lowest for the CCA dam cross (62.4%). At both locations, the SN dams produced the most weight of calf weaned per mating opportunity with the lowest values recorded by the HA and NSN dam cross at Brandon and the HSH dam cross at Manyberries with the CN dam cross recording the highest values and the CCA and ACA the lowest. For all performance criteria calves out of F1 dams had an advantage over calves from backcross dams. Key words: Beef cattle, cow productivity, crossbreeding

The effect of body condition, feed level and temporary calf separation on the post-partum anoestrous period and LH and FSH levels in beef cows

1997 ◽  
Vol 1987 ◽  
pp. 26-26
Author(s):  
I.A. Wright ◽  
A.J.F. Russel ◽  
T.K. Whyte ◽  
A.J. McBean
Keyword(s):  
Dairy Cows ◽  
Reproductive Performance ◽  
Deleterious Effect ◽  
Post Partum ◽  
Beef Cows ◽  
Biological Efficiency ◽  
Reproductive Efficiency ◽  
Beef Cow ◽  
The Mean ◽  
Farm Livestock

Compared with other species of farm livestock the reproductive performance of beef cows is poor. Mating and calving periods are frequently extended to avoid having a large proportion of barren Cows. vs. For example the ‘average’ MLC recorded herd has a calving period of over 4months. This makes management of beef cow herds difficult and has a deleterious effect on biological efficiency and profitability.One of the major limitations to improvement of reproductive efficiency in beef cattle is the extended post-partum anoestrus. Beef cows have longer post-partum anoestrous periods than dairy cows. In one study of three different herds (Peters and Riley, 1982) the mean length of the anovulatory period ranged from 24 to 88 days.

scholarly journals Effects on Synchronization and Reproductive Efficiency of Delaying the Removal of the Intravaginal Progesterone Device by 24 h in the 5d Co-synch Protocol in Heifers

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 ◽  
...  
Keyword(s):  
Animal Welfare ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Reproductive Efficiency ◽  
Beef Heifers ◽  
Animal Management ◽  
Commercial Farms ◽  
Beef Herds ◽  
Farm Economics

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.

Prepartum body condition and weight influences on reproductive performance of first-calf beef cows

1994 ◽  
Vol 72 (5) ◽  
pp. 1119-1125 ◽  
Author(s):  
S. M. DeRouen ◽  
D. E. Franke ◽  
D. G. Morrison ◽  
W. E. Wyatt ◽  
D. F. Coombs ◽  
...  
Keyword(s):  
Body Condition ◽  
Reproductive Performance ◽  
Beef Cows

scholarly journals Calving sub-season and reproductive efficiency of beef cows

2010 ◽  
Vol 39 (10) ◽  
pp. 2182-2186
Author(s):  
Cristiane Reinher ◽  
Júlio Otávio Jardim Barcellos ◽  
Vanessa Peripolli ◽  
Ênio Rosa Prates ◽  
Maria Eugênia Andrighetto Canozzi
Keyword(s):  
Pregnancy Rate ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Climate Variations ◽  
Southern Brazil ◽  
Chi Square ◽  
Chi Square Test

It was evaluated in this work the effect of calving sub-season on the pregnancy rate of 7,726 multiparous Hereford beef cows grazing on natural pastures in southern Brazil, from 1994 to 2007. Calving sub-season periods were divided in 20-day intervals from August 12th to 31st; from September 1st to 20th; from September 21st to October 10th; from October 11th to 31st; from November 1st to 20th. Calving in each sub-season and pregnancy rate (PR) were analyzed by the Chi-square test. Overall means of each sub-season were 92.7% (from August 12th to 31st), 90.6% (from September 1st to 20th), 82.1% (from September 21st to October 10th), 77.7% (from October 11th to 31st), and 70.6% (from November 1st to 20th). Calving sub-season significantly influenced pregnancy rate. Cows which calved in the initial sub-season showed higher pregnancy rates than cows which calved from the fourth calving sub-season. However this difference did not occur in 1999 and in 2007 since calving rates did not statistically differ among the five sub-seasons. In 1998 and 2004, calving rates were lower and the effects of calving sub-season on pregnancy rates were higher, possibly due to climate variations. In general, pregnancy rate decreases as calving occurs later in the year, particularly in years when the weather adversely affects pasture growth.

Effects of postpartum fat supplementation and source on the reproductive performance of lactating young beef cows grazing cool-season grass pastures

2019 ◽  
Vol 35 (2) ◽  
pp. 185-198
Author(s):  
F. Añez-Osuna ◽  
G.B. Penner ◽  
J. Campbell ◽  
D. Damiran ◽  
M.E.R. Dugan ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Beef Cows ◽  
Cool Season ◽  
Fat Supplementation ◽  
Cool Season Grass

Reproductive Performance of Beef Cows Fed Whole Soybeans Before the Breeding Interval

2008 ◽  
Vol 24 (6) ◽  
pp. 639-647 ◽  
Author(s):  
N.M. Long ◽  
G.M. Hill ◽  
J.F. Baker ◽  
W.M. Graves ◽  
D.H. Keisler ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Beef Cows

Calm Temperament Improves Reproductive Performance of Beef Cows

2014 ◽  
Vol 49 (6) ◽  
pp. 1063-1067 ◽  
Author(s):  
R Kasimanickam ◽  
M Asay ◽  
S Schroeder ◽  
V Kasimanickam ◽  
JM Gay ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Beef Cows

Geographic determinants of copper and molybdenum concentrations in serum at the end of the grazing season and associations with reproductive performance in beef cows from western Canada

2011 ◽  
Vol 91 (3) ◽  
pp. 423-431 ◽  
Author(s):  
Leanne Van De Weyer ◽  
Cheryl Waldner
Keyword(s):  
Reproductive Performance ◽  
Important Determinant ◽  
Beef Cows ◽  
Western Canada ◽  
Serum Concentrations ◽  
Soil Color ◽  
Grazing Season ◽  
Cu Deficiency ◽  
The Mean ◽  
Feed Samples

Van De Weyer, L. M. and Waldner, C. L. 2011. Geographic determinants of copper and molybdenum concentrations in serum at the end of the grazing season and associations with reproductive performance in beef cows from western Canada. Can. J. Anim. Sci. 91: 423–431. Serum concentrations of Cu and Mo were measured at the end of the summer grazing season in an observational field study of 783 breeding females from 66 cow-calf herds located in western Canada. The mean Cu concentration was 0.82 ppm (S, 0.30 ppm) and the mean Mo concentration was 0.056 ppm (S, 0.055 ppm). Serum Cu concentration differed across ecoregions (P=0.013). Serum Mo concentrations varied by ecoregion (P =0.002), soil type (P =0.011), soil color (P=0.018), and total precipitation during the growing season (P =0.004). Copper and Mo serum concentrations at the end of the grazing season were not associated with reproductive outcomes. Herd location is an important determinant of the risk of primary and secondary Cu deficiency and can inform the need for trace mineral testing of feed samples as well as supplementation.

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