scholarly journals The response to genetic merit for milk production in dairy cows differs by cow body weight

2021 ◽  
Author(s):  
D.P. Berry ◽  
R.D. Evans
1998 ◽  
Vol 1998 ◽  
pp. 188-188 ◽  
Author(s):  
S.E.M. Snijders ◽  
K. O'Farrell ◽  
M. P. Boland ◽  
P. Dillon ◽  
M. Diskin ◽  
...  

Efficient milk production in Ireland in both spring and autumn calving herds is very much dependent on compact calving. This requires an early resumption of ovarian activity, high submission rate, and pregnancy rate to service. Since 1984 there has been an increase in the genetic merit of Irish dairy herds. High genetic merit animals have reduced reproductive performance due to the demands of high milk yield (Nebel and McGilliard, 1993) and the loss of body weight and body condition (Butler and Smith, 1989). However, little comparative data on the reproductive performance of dairy cows of different genetic merit are available. The objective of this study was therefore, to determine the relationship between genetic merit of dairy cows and follicular growth patterns, milk production, body weight loss, insulin and glucose levels in early lactation.


1998 ◽  
Vol 1998 ◽  
pp. 188-188
Author(s):  
S.E.M. Snijders ◽  
K. O'Farrell ◽  
M. P. Boland ◽  
P. Dillon ◽  
M. Diskin ◽  
...  

Efficient milk production in Ireland in both spring and autumn calving herds is very much dependent on compact calving. This requires an early resumption of ovarian activity, high submission rate, and pregnancy rate to service. Since 1984 there has been an increase in the genetic merit of Irish dairy herds. High genetic merit animals have reduced reproductive performance due to the demands of high milk yield (Nebel and McGilliard, 1993) and the loss of body weight and body condition (Butler and Smith, 1989). However, little comparative data on the reproductive performance of dairy cows of different genetic merit are available. The objective of this study was therefore, to determine the relationship between genetic merit of dairy cows and follicular growth patterns, milk production, body weight loss, insulin and glucose levels in early lactation.


1999 ◽  
Vol 1999 ◽  
pp. 76-76
Author(s):  
C.P. Ferris ◽  
F.J. Gordon ◽  
D.C. Patterson ◽  
C.S. Mayne

In a previous short term study, Ferris et al. (1997) demonstrated that similar levels of nutrient intake and animal performance could be obtained by either increasing silage feed value and reducing concentrate feed level, or by reducing silage feed value and increasing concentrate feed level. The principles established in this study were incorporated into this trial to examine two systems of milk production over a full lactation, including both the winter and grazing periods.Forty high genetic merit dairy cows (PTA95 fat + protein = 38.2 kg), in their second or subsequent lactation, were used in a continuous design full lactation study. Animals had a mean calving date of 1 November and were allocated to one of two systems of milk production, HF or HC, within 36 hours of calving. During the winter, animals on system HF were offered a silage with high feed value characteristics, supplemented with 5.5 kg of concentrate (crude protein concentration of 280 g/kg DM) through an out-of-parlour feeding system.


2002 ◽  
Vol 2002 ◽  
pp. 220-220 ◽  
Author(s):  
M.D. Cooper ◽  
D. R. Arney ◽  
C. J. C. Phillips

The effects of high milk yields on the behaviour and welfare of the dairy cow are unclear. A high milk yield increases the need to consume sufficient fodder in an attempt to meet high nutrient demands. The failure to meet the demands may result in persistent hunger in the dairy cow having to modify her behaviour by employing various coping strategies. These modifications may help the cow overcome a state of hunger but at the expense of being unable to express other important behaviours. The objective of this study was therefore to determine whether the behaviour and welfare of the genetically high yielding dairy cow is being compromised by the increased nutritional demands of milk production, and to investigate the possibility that an increased amount of time spent in food-directed behaviours may have a detrimental effect on the time available to perform other important behaviours.


Reproduction ◽  
2002 ◽  
pp. 419-427 ◽  
Author(s):  
JG Gong ◽  
WJ Lee ◽  
PC Garnsworthy ◽  
R Webb

Although it has become increasingly clear that fertility in modern dairy cattle is declining in association with increased milk yields, the underlying mechanism is poorly understood. The first ovulation post partum is delayed in dairy cows undergoing selection for genetic merit for milk yield in association with lower circulating insulin concentrations. The aim of this study was to investigate whether feeding a diet to increase circulating insulin concentrations can overcome this delay in the first ovulation post partum. The experiment was a 2 x 2 factorial design (n = 10 per group) involving diet and genetic merit for milk yield. The dietary treatment started on the day of calving and lasted for 50 days. Plasma samples were collected each day and ovarian ultra-sonography was performed three times a week during the experimental feeding period. Milk yield was recorded each day, and body weight and body condition score were determined each week. Milk samples were collected three times a week from day 50 to day 105 post partum, and reproductive performance data were recorded for all the cows as part of the routine farm practice. The dietary treatment induced significant differences in plasma insulin concentrations in both high and low genetic merit cows. Although high genetic merit cows produced more milk, lost more body weight and had lower body condition scores during the experiment, no significant effect of diet was observed on these measurements. The high insulin inducing diet increased the proportion of cows ovulating within 50 days of calving and reduced the intervals from calving to first ovulation, and tended to reduce the intervals from calving to first service and to conception. These fertility parameters were also more favourable in low than in high genetic merit cows, but no interaction between diet and genetic merit was observed for any of these parameters. Genetic merit, but not diet, also affected the number of services required per conception and the conception rate. In conclusion, these results have confirmed that genetic selection for high milk yield is associated with a decrease in reproductive performance in dairy cows. More importantly, this study has demonstrated that it is possible to alleviate this problem by nutritional manipulation.


1986 ◽  
Vol 66 (1) ◽  
pp. 85-95 ◽  
Author(s):  
J. D. ERFLE ◽  
F. D. SAUER ◽  
S. MAHADEVAN ◽  
R. M. TEATHER

In two experiments, lactating cows (26 in exp. 1; 32 in exp. 2) were fed an 11.3% crude protein (CP) diet, a 14.7% CP diet containing untreated soybean meal (SBM) or a 14.6% CP diet containing formaldehyde-treated SBM (FSBM), all three fed as a complete blended diet with control corn silage (CCS) (exp. 1); a 12% CP diet, a 13.4% CP diet containing SBM or a 13.3% CP diet containing FSBM, all fed as a complete blended diet with urea-treated corn silage (UCS) (exp. 2). In both experiments concentrates and CCS or UCS were mixed (50:50 dry matter) daily and fed ad lib for a 16-wk period. The increase of CP over the low CP negative control by addition of untreated SBM resulted in a significant (P < 0.05) increase in milk production in both experiments. The addition of FSBM had no significant effect. When comparing solids-corrected milk (SCM), addition of SBM, whether treated or not, significantly increased SCM in both experiments. In neither experiment did FSBM improve milk production over untreated SBM. All animals fed CCS lost body weight but there was no difference between treatments. For animals fed UCS the low CP group lost significantly (P < 0.05) more body weight than did the group fed FSBM. Dry matter (DM) intake was significantly (P < 0.05) lower for the FSBM fed group than for the group fed untreated SBM in exp. 1 (CCS). DM intake was significantly (P < 0.05) increased by either FSBM or SBM over the low CP control fed UCS. Milk protein was the only component significantly (P < 0.05) decreased by FSBM in exp. 1. Isobutyric and isovaleric acids were significantly (P < 0.05) lower in rumen fluid of animals on FSBM plus CCS. Rumen microbial protein content seemed to be more adversely affected by FSBM with CCS than UCS. Amino acid content of FSBM and SBM demonstrated that lysine and tyrosine were lost from SBM after treatment with formaldehyde. The lack of a response in milk production to FSBM is discussed in terms of a lysine and tyrosine deficiency for milk protein synthesis and the adverse effect that formaldehyde protection of SBM may have on the rumen microbial population. Key words: Lactation, dairy cows, urea, corn silage, soybean meal, formaldehyde treatment


2005 ◽  
Vol 2005 ◽  
pp. 19-19
Author(s):  
T. Yan ◽  
R. E. Agnew ◽  
C. S. Mayne

Body condition of lactating dairy cows varies at different stages of lactation. Cows usually mobilise their body reserves to provide energy and protein for milk production in early lactation, and gain weight to deposit energy and protein for pregnancy at a later stage. The objective of the present study was to examine relationships between body condition score (CS) and body concentration of lipid, CP and energy.


1999 ◽  
Vol 132 (4) ◽  
pp. 483-490 ◽  
Author(s):  
C. P. FERRIS ◽  
F. J. GORDON ◽  
D. C. PATTERSON ◽  
M. G. PORTER ◽  
T. YAN

Sixty Holstein/Friesian dairy cows, 28 of high genetic merit and 32 of medium genetic merit, were used in a continuous design, 2 (cow genotypes)×4 (concentrate proportion in diet) factorial experiment. High and medium merit animals had Predicted Transmitting Abilities for milk fat plus protein yield, calculated using 1995 as the base year (PTA95 fat plus protein), of 43·3 kg and 1·0 kg respectively. Concentrate proportions in the diet were 0·37, 0·48, 0·59 and 0·70 of total dry matter (DM), with the remainder of the diet being grass silage. During this milk production trial, 24 of these animals, 12 from each genetic merit, representing three animals from each concentrate treatment, were subject to ration digestibility, and nitrogen and energy utilization studies. In addition, the efficiency of energy utilization during the milk production trial was calculated.There were no genotype×concentrate level interactions for any of the variables measured (P>0·05). Neither genetic merit nor concentrate proportion in the diet influenced the digestibility of either the DM or energy components of the ration (P>0·05). When expressed as a proportion of nitrogen intake, medium merit cows exhibited a higher urinary nitrogen output and a lower milk nitrogen output than the high merit cows. Methane energy output, when expressed as a proportion of gross energy intake, was higher for the medium than high merit cows (P<0·05), while urinary energy output tended to decrease with increasing proportion of concentrate in the diet (P<0·05). In the calorimetric studies, neither heat energy production, milk energy output and energy retained, when expressed as a proportion of metabolizable energy intake, nor the efficiency of lactation (kl), were affected by either cow genotype or concentrate proportion in the diet (P>0·05). However when kl was calculated using the production data from the milk production trial the high merit cows were found to have significantly higher kl values than the medium merit cows (0·64 v. 0·59, P<0·05) while k l tended to fall with increasing proportion of concentrate in the ration (P<0·05). However in view of the many assumptions which were used in these latter calculations, a cautious interpretation is required.


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