The objective of this work was to estimate the genetic variation of free fatty acids (FFA), glucose, growth hormone (GH), and insulin in juvenile male dairy calves and to assess the relationships, if present, with the fertility of their female offspring. This study used data from 1,498 (269.5 d of age +/- 11.1) male calves from a multiple ovulation and embryo transfer breeding scheme (data collected from 1997 to 2002). Calves were Danish Holstein (n = 1,047), Danish Jersey (n = 200), and Red Dane (n = 251), and were sampled following an overnight fast at approximately 9 mo of age. Plasma samples were assayed for basal FFA, glucose, GH, and insulin. Estimated breeding values of female fertility (high values indicating better fertility), based on progeny-test results for approximately 100 daughters per sire, were available for a subset (n = 810) of the male calves as adult sires. Data from Danish Holstein alone or Danish Holstein, Red Dane, and Danish Jersey combined (all breeds) were analyzed for each trait. In both data sets, the estimates of heritabilities of glucose (0.27 +/- 0.06), FFA (0.11 +/- 0.05), and insulin (0.21 +/- 0.06) were moderate, and that of GH (0.09 +/- 0.05) was low. Correlations of estimated breeding values for fertility traits with glucose and FFA breeding values were negative, indicating that male calves with high glucose or FFA had female offspring with reduced fertility. Selection for bull calves with lower concentrations of glucose and FFA following an overnight fast could result in female offspring with genetically better fertility. Glucose and FFA may therefore be of interest to enhance selection for improved female fertility, as a measurement in young bulls.

The immediate effect on dairy cow mobility, daily activity and milk yield following treatment for claw horn disease was examined in 306 lame cows located on four Cheshire dairy farms over twelve months. The daily activity and milk yield of all cows in these herds was recorded on computer using pedometers and in-parlour milk flow meters. Lame cows identified by stockmen were assessed subjectively by locomotion score, then restrained and their claws examined to identify the predominant lesion present. Those with locomotion scores ≥2.5 that presented with sole ulcer, haemorrhage and bruising, or white line disease were studied. Claws of the affected limb were trimmed by one paraprofessional claw trimmer using the five-step Dutch method and the affected claw unloaded either by trimming or application of a block to the healthy digit: those on the contra-lateral limb were trimmed similarly. The same observer repeated the locomotion score assessment seven days later: trimming reduced the proportion of lame cows (score ≥3) by 55% and those with poor gait (score ≤3 ≥2.5) by 49%, and the proportion of all cows not lame after trimming was 51% (χ 2 4.94: P≤0.001). Night time activity levels increased from 76 to 81 steps/hour on day 2 after treatment (P<0.05) but this was not maintained: daily milk yields fell by 2%. Using univariate mixed models, year and season, parity and farm all had significant effects on locomotion and activity levels. This treatment for claw horn disease in lame dairy cows improved their immediate health and welfare.

The decline of dairy cattle fertility worldwide remains a major concern, with conception rates to first service commonly below 40%. The length and severity of negative energy balance postpartum are unfavorably correlated with fertility, suggesting that the length and severity of negative energy balance and fertility are linked via several hormones or metabolites. These compounds therefore have the potential to predict fertility at a genetic level. The addition of a predictor trait for fertility into present fertility indices would accelerate genetic gain, particularly if it was expressed before adulthood. The objective of this work was to estimate the genetic variation in several metabolites and hormones in calves, and to determine their genetic relationships with fertility and production through sire predicted transmitting abilities (PTA; sires of calves sampled). Circulating concentrations of free fatty acids (FFA), glucose, growth hormone (GH), insulin, and insulin-like growth factor 1 (IGF-1) in male and female UK Holstein-Friesian dairy calves (average age +/- SD; 126 +/- 12.7 d) were analyzed during 2 studies: data set 1 (n = 496 females; 1996-2001; 7 commercial dairy herds) and data set 2 (n = 326 females, n = 256 males; 2002-2006; multiple ovulation and embryo transfer breeding scheme). Univariate mixed models were fitted to the data using ASREML. Basal concentrations of FFA, glucose, GH, insulin and total IGF-1 were all moderately heritable in both sexes (heritability range +/- SE; 0.09 +/- 0.05 to 0.66 +/- 0.14). The sire PTA for protein percentage had significant regression coefficients and approximate genetic correlations with FFA and insulin, and the sire PTA for calving interval had significant regression coefficients and approximate genetic correlations with GH. Additive genetic variance seems responsible for a moderate proportion of the phenotypic variation in important metabolites and regulatory hormones in male and female UK Holstein-Friesian dairy calves, therefore supporting further investigation into their use as juvenile predictors for fertility in the mature female.

The length and severity of negative energy balance postpartum is unfavourably correlated (genetically & phenotypically) with interval to first ovulation (de Vries & Veerkamp, 2000). During this period concentrations of free fatty acids (FFA), glucose, growth hormone (GH), insulin, insulin like growth factor 1 (IGF-1) and other hormones, all of which have links with many aspects of reproduction, are altered. A moderate heritability and genetic correlation between these parameters in the female and male (who is ultimately of most use for selection purposes) calf with female fertility could allow juvenile selection for fertility. With this in mind the objective of this study was to estimate the heritability of FFA, glucose, GH, insulin and IGF-1 concentration in male and female calves.

The immediate effect on dairy cow mobility, daily activity and milk yield following treatment for claw horn disease was examined in 306 lame cows located on four Cheshire dairy farms over twelve months. The daily activity and milk yield of all cows in these herds was recorded on computer using pedometers and in-parlour milk flow meters. Lame cows identified by stockmen were assessed subjectively by locomotion score, then restrained and their claws examined to identify the predominant lesion present. Those with locomotion scores ≥2.5 that presented with sole ulcer, haemorrhage and bruising, or white line disease were studied. Claws of the affected limb were trimmed by one paraprofessional claw trimmer using the five-step Dutch method and the affected claw unloaded either by trimming or application of a block to the healthy digit: those on the contra-lateral limb were trimmed similarly. The same observer repeated the locomotion score assessment seven days later: trimming reduced the proportion of lame cows (score ≥3) by 55% and those with poor gait (score ≤3 ≥2.5) by 49%, and the proportion of all cows not lame after trimming was 51% (χ 2 4.94: P≤0.001). Night time activity levels increased from 76 to 81 steps/hour on day 2 after treatment (P<0.05) but this was not maintained: daily milk yields fell by 2%. Using univariate mixed models, year and season, parity and farm all had significant effects on locomotion and activity levels. This treatment for claw horn disease in lame dairy cows improved their immediate health and welfare.