A.J. Seykora

Crossbreds of Jersey × Holstein Compared with Pure Holsteins for Production, Fertility, and Body and Udder Measurements During First Lactation

Jersey x Holstein crossbreds (JxH; n = 76) were compared with pure Holsteins (n = 73) for 305-d milk, fat, and protein production; conception rate; days open; proportion of cows pregnant within fixed intervals postpartum; and body and udder measurements during first lactation. Cows were housed at 2 research locations of the University of Minnesota and calved from September 2003 to May 2005. The JxH were mated to Montbeliarde sires, and Holstein cows were mated to Holstein sires. Best Prediction was used to determine actual production (milk, fat, and protein) for 305-d lactations with adjustment for age at calving, and records less than 305 d were projected to 305 d. The JxH (274 kg) and pure Holsteins (277 kg) were not significantly different for fat production, but JxH had significantly less milk (7,147 vs. 7,705 kg) and protein (223 vs. 238 kg) production than pure Holsteins. The JxH had significantly fewer days open than pure Holsteins (127 vs. 150 d). Also, a significantly greater proportion of JxH were pregnant at 150 and 180 d postpartum than pure Holsteins (75 vs. 59% and 77 vs. 61%, respectively). The JxH had significantly less body weight (60 kg) at calving, but significantly greater body condition (2.80 vs. 2.71). Furthermore, JxH had significantly less udder clearance from the ground to the bottom of the udder than pure Holsteins (47.7 vs. 54.6 cm), and greater distance between front teats (15.8 vs. 14.0 cm) than pure Holsteins during first lactation.

Crossbreds of Jersey × Holstein Compared with Pure Holsteins for Body Weight, Body Condition Score, Dry Matter Intake, and Feed Efficiency During the First One Hundred Fifty Days of First Lactation

Jersey x Holstein crossbred (JxH) cows (n = 24) were compared with pure Holstein cows (n = 17) for body weight, body condition score, dry matter intake (DMI), and feed efficiency during the first 150 d of first lactation. Cows were housed in the University of Minnesota dairy facility at the St. Paul campus and calved from September 2004 to January 2005. The JxH cows were mated by artificial insemination with Montbeliarde bulls, and Holstein cows were mated by artificial insemination with Holstein bulls. Cows were weighed and body condition was scored every other week. Cows were individually fed a TMR twice daily, and feed refusals were measured once daily. The DMI of cows was measured daily and averaged across 7-d periods. Milk production and milk composition were from monthly Dairy Herd Improvement records. Best Prediction was used to calculate actual production (milk, fat, protein) for each cow from the 4th to 150th day of first lactation. The JxH cows had significantly less body weight (467 vs. 500 kg) and significantly higher body condition scores (2.90 vs. 2.76) than pure Holstein cows. The JxH cows had significantly less milk production (4,388 vs. 4,644 kg) during the 4th to 150th day of lactation than did pure Holstein cows. However, fat plus protein production during the first 150 d of lactation was not significantly different for JxH (302 kg) and Holstein (309 kg) cows. The JxH and pure Holstein cows did not differ significantly for daily DMI (22.0 vs. 22.7 kg, respectively), and the JxH (4.7%) and pure Holstein (4.5%) cows consumed similar DMI based on percentage of body weight. Consequently, feed efficiency for the 4th to 150th day of lactation did not differ for JxH and pure Holstein cows.

Genetic parameters of milk ELISA scores for Johne's disease.

The objective of this study was to estimate genetic parameters of antibody response to Mycobacterium avium ssp. paratuberculosis using routinely collected Minnesota Dairy Herd Improvement milk ELISA tests. After all edits, 25,809 tests from 21,514 Holstein cows in 282 Johnes positive herds were available for analysis. The Johnes test results were analyzed both as a binary trait (positive or negative) and as a linear trait as the transformed ELISA optical density [ln(OD)]. Significant fixed effects in the model were age at test date, days in milk, and laboratory negative control; random effects were herd test date, animal effect, and permanent environment effect. Transformed ELISA optical density increased with age at test day and days in milk. Heritability estimates ranged from 0.065 to 0.095. Percentage of variation explained by maternal effects ranged from 1.3 to 2.29%. Repeatabilities ranged from 0.380 to 0.433. Statistically significant correlations between the sire solutions for ln(OD) for 154 bulls with at least 30 daughters in the analysis and their USDA predicted transmitting abilities were as follows: fat yield, -0.199; protein yield, -0.179; productive life, -0.292; and Net Merit, -0.339. These correlations suggest that selection for productive life or Net Merit also will improve resistance to Johnes disease.

Short communication: Jersey × Holstein crossbreds compared with pure Holsteins for production, mastitis, and body measurements during the first 3 lactations

Jersey (JE)×Holstein (HO) crossbred cows (n=76) were compared with pure HO cows (n=73) for 305-d milk, fat, and protein production, somatic cell score (SCS), clinical mastitis, lifetime production, and body measurements during their first 3 lactations. Cows were in 2 research herds at the University of Minnesota and calved from September 2003 to June 2008. Best prediction was used to determine actual production for 305-d lactations as well as lifetime production (to 1,220 d in the herd after first calving) from test-day observations. During first lactation, JE×HO cows and pure HO cows were not significantly different for fat plus protein production; however, JE×HO cows had significantly lower fat plus protein production during second (-25 kg) and third (-51 kg) lactation than pure HO cows. Nevertheless, JE×HO cows were not significantly different from pure HO cows for lifetime production or lifetime SCS. The JE×HO cows were not significantly different from pure HO cows for SCS and clinical mastitis during first and second lactations; however, JE×HO cows tended to have higher SCS (3.79) than pure HO cows (3.40), but significantly lower (-23.4%) clinical mastitis during third lactation. The JE×HO cows had significantly less hip height, smaller heart girth, less thurl width, and less pin width than pure HO cows during the first 3 lactations. Furthermore, JE×HO cows had significantly less udder clearance from the ground and significantly greater distance between the front teats than pure HO cows during their first 3 lactations.

Birth traits of pure Holstein calves versus Montbeliarde-sired crossbred calves.

Pure Holstein calves and Montbeliarde-sired crossbred calves from multiparous Holstein dams were compared for gestation length, calf weight at birth, calving difficulty, and stillbirth in 2 research herds of the University of Minnesota. The Montbeliarde-sired calves from multiparous Holstein dams had significantly longer gestation lengths (283.2 d) than Holstein-sired calves from Holstein dams (278.4 d), and Montbeliarde-sired calves from multiparous Holstein dams had significantly greater calf weight at birth (48.3kg) compared with Holstein-sired calves from Holstein dams (43.3kg). However, calves sired by Montbeliarde bulls were not significantly different from calves sired by Holstein bulls for calving difficulty and stillbirth. In addition, Jersey x Holstein crossbred cows mated to Montbeliarde artificial insemination (AI) bulls were compared with pure Holstein cows mated to Holstein AI bulls for gestation length, calf weight at birth, calving difficulty, and stillbirth at their first 3 calvings. Gestation length was significantly longer for Jersey x Holstein cows bred to Montbeliarde bulls than for pure Holstein cows bred to Holstein bulls at first calving (280.3 versus 277.7 d) and second and third calving (282.2 versus 278.6 d); however, Jeresy x Holstein cows bred to Montbeliarde AI bulls were not significantly different from pure Holstein cows bred to Holstein AI bulls for calf weight at birth, calving difficulty, and stillbirth at the first 3 calvings.

Production, fertility, survival, and body measurements of Montbéliarde-sired crossbreds compared with pure Holsteins during their first 5 lactations

Two-breed crossbreds of Montbéliarde and Holstein (MO × HO) as well as 3-breed crossbreds of Montbéliarde and Jersey/Holstein (MO × JH) were compared with pure Holstein (HO) cows for production, somatic cell score (SCS), fertility, survival to subsequent calving, mortality, and body measurements during their first 5 lactations. Cows calved for the first time between 2005 and 2010 and were housed in either a confinement herd or a herd that had access to pasture for 165d of the year in the north central region of the United States. Body, hoof, and udder measurements of cows were also objectively measured. The MO × HO crossbred cows were not different from pure HO cows for fat-plus-protein production during any lactation. However, the MO × JH crossbred cows had 5% lower fat-plus-protein production compared with pure HO cows in the confinement herd. On the other hand, the MO × JH crossbred cows were not different for fat-plus-protein production in the third to fifth lactation compared with pure HO cows in the seasonal pasture herd. Across the 2 herds, the MO × HO and MO × JH crossbred cows had 21% higher first-service conception rate, 41 fewer days open, and 12% higher pregnancy rate compared with the pure HO cows. Furthermore, the MO × HO (5%) and MO × JH (12%) crossbred cows had lower mortality rates than the pure HO cows (18%). Because of superior fertility and lower mortality rates, the MO × HO and MO × JH crossbred cows, combined, had greater survival to second (+13%), third (+24%), fourth (+25%), and fifth (+17%) lactation compared with pure HO cows. For body measurements, MO × HO were similar to pure HO cows for hip height and heart girth, but MO × HO cows had more body condition and greater body weight (+39kg) across the first 5 lactations. The MO × JH cows had more body condition but 5cm shorter hip height and 28kg less body weight than pure HO cows across the first 5 lactations. Foot angle was steeper and hoof length was shorter for MO × HO cows, but MO × JH cows were similar to pure HO cows for hoof measurements.

Short communication: Jersey × Holstein crossbreds compared with pure Holsteins for body weight, body condition score, fertility, and survival during the first three lactations

Crossbred cows (n=80) resulting from the use of Jersey (JE) semen on their pure Holstein (HO) dams were compared with pure HO cows (n=77) for body weight, body condition score, fertility, and survival during their first 3 lactations. Cows were in 2 research herds of the University of Minnesota and calved from September 2003 to June 2008. The JE × HO crossbred cows had significantly less body weight during the first (-56 kg), second (-67 kg), and third (-82 kg) lactations than pure HO cows. However, JE × HO cows had significantly greater body condition score during the first (2.94 vs. 2.84), second (2.97 vs. 2.84), and third (2.99 vs. 2.87) lactations than pure HO cows. For fertility, JE × HO cows had fewer days to first breeding during the first (-10.6d), second (-8.4d), and third (-12.3d) lactations than pure HO cows. Crossbred cows were not significantly different from pure HO cows for number of services during first lactation; however, JE × HO cows had significantly fewer services (2.2) than pure HO cows (2.7) during the second lactation. Also, JE × HO cows had significantly fewer days open than pure HO cows in the first (-24 d), second (-42 d), and third (-42 d) lactations. For survival, JE × HO cows were not significantly different from pure HO cows for percentage of cows calving a second time; however, a tendency existed for a higher percentage of JE × HO cows (63.8%) than pure HO cows (49.4%) to calve a third time, and a higher percentage of JE × HO cows calved a third time within 28, 34, and 40 mo of first calving than pure HO cows.

Montbéliarde-sired crossbreds compared with pure Holsteins for dry matter intake, Production, And body traits during the first 150 days of first lactation

Montbéliarde (MO)-sired crossbred cows (n=57) were compared with pure Holstein (HO) cows (n=40) for dry matter intake (DMI), production, hip height, body condition score (BCS), and body weight (BW) during the first 150 d of first lactation. Also, production for 305 d was compared for first lactation. The MO-sired crossbred cows were composed of MO × HO cows (n=33) and MO × Jersey/HO cows (n=24). Cows were individually fed a total mixed ration twice daily. The DMI was measured for the first 150 d of lactation, except from d 1 to 3 postpartum to permit cows to acclimate to stalls in a confinement barn. Hip height was measured once between 20 and 172 d postpartum, and BCS and BW were recorded every other week. The MO-sired crossbred cows did not differ from the pure HO cows for 150-d DMI, 150-d fat plus protein production, or for 305-d fat plus protein production. Hip height was similar for MO × HO and pure HO cows, but MO × Jersey/HO cows had shorter hip height than the pure HO cows. Despite the lack of difference for DMI, the MO-sired crossbred cows had significantly greater BCS (3.30 vs. 2.74) and BW (551 vs. 528 kg) than the pure HO cows. The MO-sired crossbred cows (122 d) had fewer days open than the pure HO cows (150 d). The higher BCS of the MO-sired crossbred cows, especially during early lactation, may have provided an advantage for fertility. Differences for DMI between breed groups were not studied for the latter half of first lactation or for multiparous cows.