scholarly journals Comparison of rebreeding policies for Ontario dairy herds

1997 ◽  
Vol 77 (4) ◽  
pp. 585-591 ◽  
Author(s):  
J. C. B. Plaizier ◽  
G. J. King ◽  
J. C. M. Dekkers ◽  
K. Lissemore
Keyword(s):  
Decision Support ◽  
Simulation Model ◽  
Milk Production ◽  
Reproductive Performance ◽  
Optimal Policy ◽  
Dairy Herds ◽  
Net Revenue ◽  
Dynamic Stochastic ◽  
Stochastic Simulation Model ◽  
Using Data

Net-revenues of rebreeding policies that differed in the maximum allowable days after calving for breeding were compared using data generated by a dynamic stochastic simulation model of Ontario dairy herds. Such comparisons benefit farmer decision support, as rebreeding decisions are important management choices. Rebreeding up to 168 d after calving only was least optimal. Hence, the rebreeding period should not be too short. At average and high herd fertility, a rebreeding policy under which cows with a mature equivalent milk production level lower than 80%, between 80 and 100%, and greater than 100% of the herd average were not rebred, bred up to 168 d after calving, and bred up to 250 d after calving, respectively, resulted in higher net-revenue than rebreeding policies that used a single cut-off for all cows. Differences in net-revenue between the optimal and the least optimal policy were $217.90 and $114.40 per cow per year for the lowest and highest simulated reproductive performance, respectively. At low herd fertility, rebreeding up to 364 d postpartum was optimal. However, at this level of performance emphasis should be given to improving fertility, rather than choice of rebreeding policy. Key words: Dairy cattle, simulation, economics, insemination policy, rebreeding policy

scholarly journals Estimating the economic impact of subclinical ketosis in dairy cattle using a dynamic stochastic simulation model

animal ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 145-154 ◽  
Author(s):  
P.F. Mostert ◽  
E.A.M. Bokkers ◽  
C.E. van Middelaar ◽  
H. Hogeveen ◽  
I.J.M. de Boer
Keyword(s):  
Dairy Cattle ◽  
Simulation Model ◽  
Economic Impact ◽  
Stochastic Simulation ◽  
Subclinical Ketosis ◽  
Dynamic Stochastic ◽  
Stochastic Simulation Model

scholarly journals Effect of milk production on reproductive performance in dairy herds

2018 ◽  
Vol 101 (8) ◽  
pp. 7575-7584 ◽  
Author(s):  
R. Rearte ◽  
S.J. LeBlanc ◽  
S.G. Corva ◽  
R.L. de la Sota ◽  
I.M. Lacau-Mengido ◽  
...  
Keyword(s):  
Milk Production ◽  
Reproductive Performance ◽  
Dairy Herds

scholarly journals Impact of frequency of milking on milk yield and fertility of Holstein cows undergoing extended lactations due to failure to conceive

2021 ◽  
pp. 113
Author(s):  
Jesús Mellado ◽  
Jessica Flores ◽  
Francisco G. Véliz ◽  
Ángeles de Santiago ◽  
José E. García ◽  
...  
Keyword(s):  
Observational Study ◽  
Milk Production ◽  
Milk Yield ◽  
Reproductive Performance ◽  
The Other ◽  
Holstein Cows ◽  
Dairy Herds ◽  
Northern Mexico ◽  
Total Milk ◽  
Services Per Pregnancy

The objective of this observational study was to determine the effect of two (2x) compared to three (3x) times a day milking in Holstein cows undergoing lactations ≥600 d on milk production and reproductive performance. Two large adjacent commercial dairy herds with similar size, facilities, and management in a hot area of northern Mexico (25° N) were used. Cows in one herd (n= 214) were milked two times a day (2x), the other herd was milked three times a day (3x; n=245) and both groups were milked for at least 600 days. For cows in first lactation, total milk yield did not differ between 3x and 2x cows (19796 ± 3354 vs. 19269 ± 3652 kg; p > 0.10) in lactations with an average of 696 and 650 days in milk (DIM), respectively. Multiparous 3x cows produced more total milk days than 2x cows (20942 ± 3920 vs. 18910 ± 2632 kg; p < 0.01) with greater (p < 0.01) DIM for 3x (685 ± 117 days) than 2x (631 ± 88 days) cows. Lactation persistence was greater (p < 0.05) in 2x (62 ± 9%) than 3x (60 ± 10%) cows. Overall conception rate (CR) did not differ between 2x and 3x cows (53.3% vs. 49.8%) but 3x cows required one more service (p < 0.01) to get pregnant than 2x animals.  Given that average milk yield throughout the complete lactation did not differ between 2x (29.8 ± 2.0 kg) and 3x (29.3 ± 2.9 kg) cows, it was concluded that two-times-a-day milking is equally effective as three-times-a-day milking to attain acceptable milk yield in lactations over 600 days. However, reproductive performance based on first-service CR and services per pregnancy was negatively affected by three-times-a-day milking.

scholarly journals Relationship of dairy heifer reproduction with survival to first calving, milk yield and culling risk in the first lactation

2020 ◽  
Vol 33 (8) ◽  
pp. 1360-1368 ◽  
Author(s):  
István Fodor ◽  
Zsolt Lang ◽  
László Ózsvári
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Reproductive Performance ◽  
Proportional Hazards ◽  
Cox Proportional Hazards ◽  
Dairy Herds ◽  
Cox Proportional Hazards Models ◽  
Holstein Friesian ◽  
Younger Age ◽  
Relationship Of

Objective: The aim of our study was to determine the associations of heifer reproductive performance with survival up to the first calving, first-lactation milk yield, and the probability of being culled within 50 days after first calving.Methods: Data from 33 large Holstein-Friesian commercial dairy herds were gathered from the official milk recording database in Hungary. The data of heifers first inseminated between January 1, 2011 and December 31, 2014 were analyzed retrospectively, using Cox proportional hazards models, competing risks models, multivariate linear and logistic mixed-effects models.Results: Heifers (n = 35,128) with younger age at conception were more likely to remain in the herd until calving, and each additional month in age at conception increased culling risk by 5.1%. Season of birth was related to first-lactation milk yield (MY1; n = 19,931), with cows born in autumn having the highest milk production (p<0.001). The highest MY1 was achieved by heifers that first calved between 22.00 and 25.99 months of age. Heifers that calved in autumn had the highest MY1, whereas calving in summer was related to the lowest milk production (p<0.001). The risk of culling within 50 days in milk in first lactation (n = 21,225) increased along with first calving age, e.g. heifers that first calved after 30 months of age were 5.52-times more likely to be culled compared to heifers that calved before 22 months of age (p<0.001). Calving difficulty was related to higher culling risk in early lactation (p<0.001). Heifers that required caesarean section were 24.01-times more likely to leave the herd within 50 days after first calving compared to heifers that needed no assistance (p<0.001).Conclusion: Reproductive performance of replacement heifers is closely linked to longevity and milk production in dairy herds.

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