Identifying efficient dairy heifer producers using production costs and data envelopment analysis.

During November and December 2011, data were collected from 44 dairy operations in 13 Pennsylvania counties. Researchers visited each farm to collect information regarding management practices and feeding, and costs for labor, health, bedding, and reproduction for replacement heifers from birth until first calving. Costs per heifer were broken up into 4 time periods: birth until weaning, weaning until 6 mo of age, 6 mo of age until breeding age, and heifers from breeding to calving. Milk production records for each herd were obtained from Dairy Herd Improvement. The average number of milking cows on farms in this study was 197.8 ± 280.1, with a range from 38 to 1,708. Total cost averaged $1,808.23 ± $338.62 from birth until freshening. Raising calves from birth to weaning cost $217.49 ± 86.21; raising heifers from weaning age through 6 mo of age cost $247.38 ± 78.89; raising heifers from 6 mo of age until breeding cost $607.02 ± 192.28; and total cost for bred heifers was $736.33 ± 162.86. Feed costs were the largest component of the cost to raise heifers from birth to calving, accounting for nearly 73% of the total. Data envelopment analysis determined that 9 of the 44 farms had no inefficiencies in inputs or outputs. These farms best combined feed and labor investments, spending, on average, $1,137.40 and $140.62/heifer for feed and labor. These heifers calved at 23.7 mo of age and produced 88.42% of the milk produced by older cows. In contrast, the 35 inefficient farms spent $227 more on feed and $78 more on labor per heifer for animals that calved 1.6 mo later and produced only 82% of the milk made by their mature herdmates. Efficiency was attained by herds with the lowest input costs, but herds with higher input costs were also able to be efficient if age at calving was low and milk production was high for heifers compared with the rest of the herd.

The effect of sire selection on cow mortality and early lactation culling in adverse and favorable cow survival environments.

The objective of this study was to determine the extent that genetic selection can help reduce dairy cow mortality and early lactation culling in adverse cow survival environments. Two datasets were constructed. The first contained 100,911 mortality records and 171,178 sixty-day culling records from 1467 herds. Cows that left the herd (culled or died) from 21 days prior to a due date through 60 days in milk were considered a 60-day cull. Cows were classified as belonging to herds with adverse cow survival environments (≥ 4.4% mortality rate and ≥ 7.1% 60-day cull rate) or favorable cow survival environments (<4.4% mortality rate and <7.1% 60-day cull rate). The second dataset included 20,438 mortality records and 34,942 sixty-day culling records from 314 herds with a known herd management system. Cows from both datasets were stratified into quartiles based on their sire's predicted transmitting ability (PTA) for productive life and other traits. Cows in the first dataset were also stratified into high (>50th percentile) and low (≤ 50th percentile) groups based on their sire's PTA for daughter calving ease and daughter stillbirth rates. Mortality and 60-day culling in the first dataset were evaluated with logistic regression models with the independent effects of sire PTA quartile, cow survival environment (adverse or favorable), the interaction of sire PTA quartile with cow survival environment, lactation number, age within lactation number, and herd-calving-cluster. The second dataset was analyzed in the same manner, but with cow survival environment replaced by herd management system. The estimated proportion of lactations that ended in death declined from 9.0% to 6.8% and 60-day culling incidence from 7.6% to 4.9% as sire productive life PTA went from the lowest to highest quartile in adverse cow survival environments. The corresponding reduction in mortality (0.7%) and 60-day culling (0.9%) were also significant in favorable cow survival environments. Mortality and 60-day culling both declined by 2.0% from low to high sire productive life PTA quartile in complete confinement free-stalls, which was the most unfavorable herd management system for cow survival. Daughters of bulls with high somatic cell score PTA and low daughter pregnancy rate PTA had higher incidences of mortality and 60-day culling, and 60-day culling was higher for daughters of sires with high milk and protein yield PTA. Selection to reduce stillbirth risk was associated with less mortality and 60-day culling, whereas mortality risk was reduced in favorable cow survival environments with selection to lower the incidence of stillbirths and calving difficulty. In conclusion, this study provides evidence that sire selection can play an important role in reducing the incidence of mortality and early lactation culling, particularly in herds with adverse cow survival environments.

Mortality, culling by sixty days in milk, and production profiles in high- and low-survival Pennsylvania herds.

The objectives were to describe culling patterns and reasons for culling across lactation, estimate mortality and the proportion of cows leaving from 21 d before an expected calving date through 60 d in milk (DIM; CULL60) for Pennsylvania (PA) dairy herds, and to describe production measures for herds with high and low mortality and CULL60. Weekly culling frequencies and reasons for culling from 3 wk before a reported expected calving date through >or= 100 wk of lactation were calculated for all PA cows with at least 1 Dairy Herd Improvement test in 2005. It was estimated that at least 5.0% of PA dairy cows died in 2005, and that at least 7.6% were culled by 60 DIM. The majority of cows exiting the herd by 60 DIM either died (35.1%) or had a disposal code of injury/other (29.9%). A total of 137,951 test-day records from 20,864 cows in herds with high mortality (>8.0%) and CULL60 (>12.0%) and 136,906 test-day records from 12,993 cows in herds with low mortality (<1.4%) and CULL60 (<2.9%) were retained to describe differences among herds with high and low survival. Least squares means for weekly milk yield, fat and protein percentages, and somatic cell score (SCS) were estimated with a model that included fixed effects for herd environment (high or low survival) and week nested within herd environment and lactation; random effects were cow, herd-test-day, and error. Cows from herds with high mortality and CULL60 produced more milk in lactations 1 (+1.9 +/- 0.15 kg/d) and 2 (+0.9 +/- 0.16 kg/d), but less in lactations 4 (-0.7 +/- 0.22 kg/d), 5 (-1.4 +/- 0.29 kg/d), and >or= 6 (-0.7 +/- 0.32 kg/d) and had higher SCS (+0.24 +/- 0.02), more change in early-lactation fat percentage (-1.77% vs. -1.59%), and a greater frequency of fat-protein inversions (3.6 +/- 0.3%). There is an opportunity to manipulate management practices to reduce mortality and early-lactation culling rates, which will improve cow welfare and the efficiency of dairy production by capturing a greater proportion of potential lactation milk yield, increasing cow salvage values, and reducing replacement costs.

The effect of synchronization on genetic parameters of reproductive traits in dairy cattle.

Genetic evaluation and selection is one strategy for improving female reproductive performance. Many producers use synchronization of ovulation or estrus to manage reproduction. The objective of this study was to examine the effects of reproductive synchronization on genetic parameter estimates of days to first breeding (DFB), days open (DO), and pregnancy rate at 120 d postpartum (PR120). Data were collected from 64 producers participating in an artificial insemination progeny testing program and using Dairy Comp 305 herd management software to record reproductive treatments and events. Data included 18,359 records for DFB and 16,379 records for DO and PR120. Synchronization was classified by breeding codes at time of insemination. The traits DFB and DO were analyzed using a linear model with age at calving, herd-year-season, and parity as fixed effects and sire and residual as random effects. For PR120, a threshold sire model was used with fixed effects as in the DFB and DO models. Three models were applied to the complete data sets of all traits; a base model with no synchronization effect, an expanded model with a fixed synchronization effect, and an interaction model with a random sire by herd management interaction. Herd management categories were based on an individual herd's use of synchronization protocols. Also, data subsets were analyzed separately based on cow synchronization treatment and herd management categories. Synchronized records for DFB had on average 40% higher sire variance and 60% lower residual variance than nonsynchronized records. Heritability for DFB ranged from 0.01 to 0.09. Sire variance was 40% lower for DO and 25% lower for PR120 in first synchronized records than either later-synchronized or nonsynchronized records. Residual variances for DO varied by 3% among cow treatment categories and 14% for herd management categories. Heritabilities ranged from 0.03 to 0.07 for DO and 0.10 to 0.26 for PR120. Including a fixed effect for synchronization in the DO model reduced sire variance by 33% and residual variance by 10%. Sire by herd management interactions were less than 2% of the total variance for all traits. Accounting for synchronization, especially for DFB, may improve accuracy of genetic parameter estimates and animal evaluations.

Accounting for pregnancy diagnosis in predicting days open.

The system for estimating days open for cows with no subsequent lactation was examined to determine if estimates should vary depending on pregnancy diagnosis. Pregnancy diagnosis information was unavailable when the original prediction system was developed, but collection was begun in 2002. New prediction equations were estimated from nearly 1.1 million Holstein lactations for 20-d intervals from 110 to 250 days in milk (DIM). Use of pregnancy diagnosis improved accuracy compared with the original system. The improvement was particularly evident for lactations of cows confirmed to be open in the 130-to-149 DIM interval, where predicted days open increased by > 96 d. For lactations of cows with a confirmed pregnancy, predicted days open decreased by 18 d for the same interval. Prediction errors decreased with increasing DIM. Jersey lactations averaged fewer days open, but in most cases Holstein solutions provided adequate predictions. Specific adjustments were generated for Jersey lactations with no breedings reported. Those adjustments reduced the predicted days open averaged across parity by an amount that increased from 9 to 27 d with DIM interval. The new prediction equations were implemented for November 2004 evaluations for daughter pregnancy rate.

Genetic evaluation of calving ease for Brown Swiss and Jersey bulls from purebred and crossbred calvings.

The objective of this study was to examine the feasibility of implementing routine national calving ease (CE) genetic evaluations of Brown Swiss (BS) and Jersey (JE) sires that include records of crossbred calvings. Records were available for 11,793 BS calvings, 3431 BS-sired crosses, 65,293 JE calvings, and 7090 JE-sired crosses. Evaluations were performed for each breed using only purebred calvings and using both purebred and crossbred calvings. In the latter evaluations, the sire-maternal grandsire model used for the routine evaluation of Holstein (HO) CE was modified to include a fixed breed composition effect to account for differences between purebred and crossbred calvings. Jersey cows had very little calving difficulty (0.5 to 0.7%) and JE bulls had a very small range of evaluations, suggesting that a routine JE evaluation would be of little value. Results from the BS evaluations suggest a routine evaluation would provide BS breeders with a useful tool for genetic improvement. Further examination of data showed that many BS calvings were in mixed herds with HO calvings. As a result, a joint evaluation for BS and HO bulls was developed. The BS data showed that there is similar genetic variability as found in the HO population, which suggests implementation of a routine evaluation including BS CE would be of value. It appears BS bulls may produce daughters with superior maternal calving ability compared with HO. Validation of the joint evaluation was performed by comparing results with the routine HO evaluation. Holstein solutions from the joint evaluation were comparable to results from the routine HO-only evaluation. Correlations among solutions and evaluations showed HO evaluations were not adversely affected by BS data and BS sires were reranked as compared with the BS-only evaluation.

Genetic parameters for test-day electrical conductivity of milk for first-lactation cows from random regression models.

Electrical conductivity (EC) of milk has been introduced as an indicator trait for mastitis during the last few decades. The correlation of EC to mastitis, easy access to EC data, and the low cost of recording are properties that make EC a good indicator trait for mastitis. In this study, EC was measured daily during the lactation and available from 2101 first-lactation Holstein cows in 8 herds in the United States. Data were analyzed with an animal model that included herd-test-day, age at calving and days in milk (DIM) as fixed effects, and random additive genetic and permanent environmental effects. A repeatability model and 5 random regression (RR) models with increasing order of Legendre polynomials were used. The goodness of fit for the different models was evaluated based on several tests. Our results indicate that the best model was a RR model with a fourth-order Legendre polynomial for both additive genetic and permanent environmental effects. Heritability estimates obtained with this model were from 0.26 to 0.36. Due to the relatively high heritability obtained for EC of milk, EC might be a potential indicator trait to use in a breeding program designed to reduce the incidence of mastitis.