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Associations between the time of conception and the shape of the lactation curve in early lactation in Norwegian dairy cattle.

Andersen F, Østerås O, Reksen O, Toft N, Gröhn YT - Acta Vet. Scand. (2011)

Bottom Line: Lactation curves characterized by a low intercept and a steep ascending slope and a steep descending slope were associated with early conception across all parities.The peak milk yield was not associated with time of conception.A practical application of the study results is the use of the shape of the lactation curve in future herd management.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Production Animal Clinical Sciences, Norwegian School of Veterinary Science, Oslo, Norway. fredrik.andersen@nvh.no

ABSTRACT

Background: This study was carried out to determine if an association exists between the shape of the lactation curve before it is influenced by the event of conception and the time from calving to conception in Norwegian dairy cattle. Lactation curves of Norwegian Red cows during 5 to 42 days in milk (DIM) were compared between cows conceiving between 43 and 93 DIM and cows conceiving after 93 DIM.

Methods: Data from 23,049 cows, represented by one lactation each, with 219,538 monthly test days were extracted from the Norwegian Dairy Herd Recording System, which represents 97% of all Norwegian dairy cows. Besides veterinary treatments, these records also included information on daily milk yield at monthly test days. The data were stratified by parity groups (1, 2, and 3 and higher) and time to conception periods (43-93 DIM and >93 DIM). The sample was selected using the following selection criteria: conception later than 42 DIM, calving season July to September, no records of veterinary treatment and the level of energy fed as concentrates between 8.69 and 12.83 MJ. The shape of the lactation curves were parameterized using a modified Wilmink-model in a mixed model analysis. Differences in the parameters of the lactation curves with different conception times were evaluated using confidence intervals.

Results: Lactation curves characterized by a low intercept and a steep ascending slope and a steep descending slope were associated with early conception across all parities. The peak milk yield was not associated with time of conception.

Conclusions: A practical application of the study results is the use of the shape of the lactation curve in future herd management. Groups of cows with impaired reproductive performance may be identified due to an unfavorable shape of the lactation curve. Monitoring lactation curves and adjusting the feeding strategy to adjust yield therefore may be useful for the improvement of reproductive performance at herd level.

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Lactation curves from 5 to 42 DIM of lactations with calving season July to September, average of 8.69 MJ to 12.53 MJ of daily energy from concentrates and no records of veterinary treatments throughout lactation, of Norwegian dairy cattle during the period 2005 to 2007. 6,883 first parity lactations with early conception (43 to 93 DIM) (▬▬), 5,875 first parity lactations with late conception (after 93 DIM) (▬▬), 3,131 second parity lactations with early conception (43 to 93 DIM) (▬ ▬), 2,520 second parity lactations with late conception (after 93 DIM) (▬ ▬), 2,574 third or later parity lactations with early conception (43 to 93 DIM) (▪ ▪ ▪) and 2,006 third or later parity lactations with late conception (after 93 DIM) (▪ ▪ ▪).
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Figure 2: Lactation curves from 5 to 42 DIM of lactations with calving season July to September, average of 8.69 MJ to 12.53 MJ of daily energy from concentrates and no records of veterinary treatments throughout lactation, of Norwegian dairy cattle during the period 2005 to 2007. 6,883 first parity lactations with early conception (43 to 93 DIM) (▬▬), 5,875 first parity lactations with late conception (after 93 DIM) (▬▬), 3,131 second parity lactations with early conception (43 to 93 DIM) (▬ ▬), 2,520 second parity lactations with late conception (after 93 DIM) (▬ ▬), 2,574 third or later parity lactations with early conception (43 to 93 DIM) (▪ ▪ ▪) and 2,006 third or later parity lactations with late conception (after 93 DIM) (▪ ▪ ▪).

Mentions: The estimates from the models were used to generate different lactation curves of early and late conceivers (Figure 2). These values and their standard errors were also used directly as parameters for the milk yield at the onset of lactation (β0), the ascending slope (β1) and descending slope (β2), which were compared between TIME_CC classes using confidence intervals (Table 2). Finally the β-values were used for calculation of peak milk yield (-β1/β2) and the day of peak milk yield (β0+(β1×ln(peak milk yield))+ (β2×peak milk yield)).


Associations between the time of conception and the shape of the lactation curve in early lactation in Norwegian dairy cattle.

Andersen F, Østerås O, Reksen O, Toft N, Gröhn YT - Acta Vet. Scand. (2011)

Lactation curves from 5 to 42 DIM of lactations with calving season July to September, average of 8.69 MJ to 12.53 MJ of daily energy from concentrates and no records of veterinary treatments throughout lactation, of Norwegian dairy cattle during the period 2005 to 2007. 6,883 first parity lactations with early conception (43 to 93 DIM) (▬▬), 5,875 first parity lactations with late conception (after 93 DIM) (▬▬), 3,131 second parity lactations with early conception (43 to 93 DIM) (▬ ▬), 2,520 second parity lactations with late conception (after 93 DIM) (▬ ▬), 2,574 third or later parity lactations with early conception (43 to 93 DIM) (▪ ▪ ▪) and 2,006 third or later parity lactations with late conception (after 93 DIM) (▪ ▪ ▪).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3044102&req=5

Figure 2: Lactation curves from 5 to 42 DIM of lactations with calving season July to September, average of 8.69 MJ to 12.53 MJ of daily energy from concentrates and no records of veterinary treatments throughout lactation, of Norwegian dairy cattle during the period 2005 to 2007. 6,883 first parity lactations with early conception (43 to 93 DIM) (▬▬), 5,875 first parity lactations with late conception (after 93 DIM) (▬▬), 3,131 second parity lactations with early conception (43 to 93 DIM) (▬ ▬), 2,520 second parity lactations with late conception (after 93 DIM) (▬ ▬), 2,574 third or later parity lactations with early conception (43 to 93 DIM) (▪ ▪ ▪) and 2,006 third or later parity lactations with late conception (after 93 DIM) (▪ ▪ ▪).
Mentions: The estimates from the models were used to generate different lactation curves of early and late conceivers (Figure 2). These values and their standard errors were also used directly as parameters for the milk yield at the onset of lactation (β0), the ascending slope (β1) and descending slope (β2), which were compared between TIME_CC classes using confidence intervals (Table 2). Finally the β-values were used for calculation of peak milk yield (-β1/β2) and the day of peak milk yield (β0+(β1×ln(peak milk yield))+ (β2×peak milk yield)).

Bottom Line: Lactation curves characterized by a low intercept and a steep ascending slope and a steep descending slope were associated with early conception across all parities.The peak milk yield was not associated with time of conception.A practical application of the study results is the use of the shape of the lactation curve in future herd management.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Production Animal Clinical Sciences, Norwegian School of Veterinary Science, Oslo, Norway. fredrik.andersen@nvh.no

ABSTRACT

Background: This study was carried out to determine if an association exists between the shape of the lactation curve before it is influenced by the event of conception and the time from calving to conception in Norwegian dairy cattle. Lactation curves of Norwegian Red cows during 5 to 42 days in milk (DIM) were compared between cows conceiving between 43 and 93 DIM and cows conceiving after 93 DIM.

Methods: Data from 23,049 cows, represented by one lactation each, with 219,538 monthly test days were extracted from the Norwegian Dairy Herd Recording System, which represents 97% of all Norwegian dairy cows. Besides veterinary treatments, these records also included information on daily milk yield at monthly test days. The data were stratified by parity groups (1, 2, and 3 and higher) and time to conception periods (43-93 DIM and >93 DIM). The sample was selected using the following selection criteria: conception later than 42 DIM, calving season July to September, no records of veterinary treatment and the level of energy fed as concentrates between 8.69 and 12.83 MJ. The shape of the lactation curves were parameterized using a modified Wilmink-model in a mixed model analysis. Differences in the parameters of the lactation curves with different conception times were evaluated using confidence intervals.

Results: Lactation curves characterized by a low intercept and a steep ascending slope and a steep descending slope were associated with early conception across all parities. The peak milk yield was not associated with time of conception.

Conclusions: A practical application of the study results is the use of the shape of the lactation curve in future herd management. Groups of cows with impaired reproductive performance may be identified due to an unfavorable shape of the lactation curve. Monitoring lactation curves and adjusting the feeding strategy to adjust yield therefore may be useful for the improvement of reproductive performance at herd level.

Show MeSH