The aim of this study was to determine whether feed intake amount and feed intake behaviour could be related to oestrus in dairy cows. Furthermore, we investigated whether oestrus had an effect on daily milk yield. A total of 138 oestrus cycles, leading to conception of 100 cows, were analysed. The parameters “daily fresh matter intake amount (kg)”, “daily number of visits to the feeding trough” and “time spent feeding per day (min)” were electronically measured and recorded. For a sub-quantity of all animals, daily milk yield (kg) was recorded continuously and stored in the herd management software. Special attention was given to the day of oestrus, which was defined as the day of successful insemination. All remaining days of the oestrus cycle were considered as the reference period. Among all animals and cycles, fresh matter intake amount per day, number of visits per day, and time spent feeding per day were reduced by 10.3, 9.1 and 20.8 %, respectively, on the day of oestrus. Fresh matter intake was significantly lower in primiparous cows than in multiparous cows. However, number of visits to the trough and time spent feeding per day were significantly higher in primiparous cows compared to multiparous cows. Day of oestrus did not have a significant effect on daily milk yield, as this parameter was characterized by high variation among all days of the oestrus cycle. In conclusion, if an RIC system is used, monitoring of feeding behaviour appears to be a potential auxiliary aid in oestrus detection.
At 35 %, fertility management is the factor exerting the highest
influence on fertility (Bostedt, 2006). One very important part of fertility
management is heat detection. When compared to older cows, heifers show reduced oestrus
intensity (Gwazdauskas et al., 1983). This can also be observed in high-yielding dairy
cows, accompanied by a decreased length of oestrus (Lopez et al., 2004).
Therefore, visual heat detection becomes more problematic and is also associated
with a high expenditure of time. To support visual heat detection, more complex and
computer-based methods have been developed. Pedometers, used for
measurements of daily physical activity in dairy cows, have proven that
movement activity is about 4 times higher during oestrus when housed in
free stalls, and about 2.75 times higher in comfort stalls compared to the
other stages of the oestrus cycle (Kiddy, 1977). Similar results were
determined by Schofield et al. (1991), who found increased activity levels in cows
on the day of oestrus by a mean factor of 2.3. Furthermore, rumination time is
significantly reduced during oestrus. Using a microphone-based sensor system
for continuous recording of rumination time, an average decrease of 17 %
(74 min d
The aim of the study was to determine whether oestrus in dairy cows also had an effect on feed intake amount, feed intake behaviour and milk yield. Furthermore, the effect of parity on investigated feed intake parameters was analysed. Additionally, the investigation should answer the question of whether the decrease in daily rumination time during oestrus described by Reith and Hoy (2012) is caused by the decrease in feed intake, as expected.
The study was conducted at the Educational and Research Centre for Animal Husbandry Hofgut Neumühle, located in Münchweiler an der Alsenz in Rhineland-Palatinate, Germany. A total of 100 lactating Holstein-Friesian dairy cows born during the period between 2004 and 2010 were analysed. The number of lactations ranged from 1 to 6, with an average of 2.46 lactations. The data collection included 138 oestrus cycles leading to conception (32 cycles of the first lactation and 106 cycles of higher lactations).
The investigation was performed in a free-stall barn consisting of two different sectors – the sector of production and the experimental sector – in which all cows of this study were housed. The experimental sector was a separate part of the stable with 60 cubicles and 30 feeding troughs. Generally closed with a gate, the troughs are equipped with an RIC (Roughage Intake Control) automatic weighing system, manufactured by Insentec B.V. (Marknesse, the Netherlands). The system identifies each animal by scanning the individual transponder, installed within the cow's collar, via light barriers. Once identified, the gate permits access to the feeding trough and the scale automatically records the amount of feed consumed at each visit. Therefore, all visits of each cow to the trough with feed intake and the duration of each visit were recorded by the system. The milking parlour used was a combination of a herringbone parlour offering space for 8 cows and a side-by-side parlour for 10 cows, manufactured by GEA Farm Technologies (located in Bönen, Germany).
Cows were fed a total mixed ration (TMR) ad libitum containing 46.6 % dry matter. The TMR was composed for dairy cows of a mean live weight of 650 kg, a mean feed intake of 21.7 kg dry matter per day and a mean milk production of 34 kg per day. For detailed composition and the ingredients of the experimental ration, see Table 1.
Cows were milked two times a day at 05:00 and at 15:30. Feeding troughs were filled once a day at around 06:30 with around 80–85 kg of feed after the leftover feed of the previous day was removed. During milking in the morning, troughs were closed for cleaning for 20 to 30 min. Fresh water was freely available at any time of the day. Date of birth, insemination, calving, length of gestation, number of lactations and daily milk yield were stored and provided by the herd management program DairyPlan C21 (GEA Farm Technologies). The day of oestrus (day 0) was defined as the day of successful insemination, detected either by visual observation and/or physical activity measurement.
Composition and ingredients of the TMR.
Means of investigated parameters and differences between the day of oestrus (day 0) and the reference period (Rp) and between primiparous (Pp) and multiparous (Mp) cows.
Rp: reference period; Pp: primiparous cows; Mp: multiparous cows;
FMI: fresh matter intake; DMI: dry matter intake; SE: standard
error.Means with different superscripts within a column differ significantly
(
Data of 262 oestrus cycles were collected in the time period from 17 May 2010
to 3 July 2012 and based on a number of 146 animals. Due to missing data for
1 or more days of the oestrus cycle in 124 recorded cycles, the data set
was reduced to 138 cycles (100 animals). The three parameters “daily feed
intake amount (kg)”, “daily number of visits to the feeding trough” and
“time spend feeding per day (min)” (
The statistical analysis of all data was performed with the program
package SPSS 20.0 (SPSS Inc., Chicago, IL, USA). Using descriptive
statistics, normal distributions were assessed for all variables by means of the
Kolmogorov–Smirnov test. Using analysis of variance (GLM), “daily fresh
matter intake amount (kg)”, “daily dry matter intake amount (kg)”, “daily
number of visits to the feeding trough” and “time spent feeding per day
(min)” were analysed for influences of oestrus and parity. Therefore, the
day of oestrus (day 0) was compared to the reference period. To determine
the effect of parity, primiparous cows were analysed for differences with
multiparous cows. The following factors were included in the fixed model
(GLM):
Means of investigated parameters during, and differences between, the reference period and the day of oestrus (day 0) for primiparous and multiparous cows.
Rp: reference period; Pp: primiparous cows; Mp: multiparous cows;
FMI: fresh matter intake; DMI: dry matter intake; SE: standard
error.
The parameter “daily milk yield” was analysed for significant differences
between all days of the oestrus cycle by means of the Student–Newman–Keuls test.
Differences among means with
On average, cows consumed 42.5 kg d
Including 2898 values a mean number of 48.5 visits to the feeding trough
per cow and day was evaluated. On average, cows visited the feeding trough
46.2 times on the day of oestrus and 50.8 times during the reference period
(9.1 % less) (Table 2). However, this difference was not significant.
Parity significantly affected this parameter (
On average, cows spent 190.8 min d
Average daily milk yield of cows was 43.8 kg d
Means of daily milk yield (kg) during the oestrus cycle (
In the current study an average daily fresh matter intake of 42.5 kg (19.8 kg dry matter) per cow and day was analysed. Ulbrich et al. (2004) described a dry matter intake of 23.5 kg as necessary for cows of a body weight of 650 kg producing 40 kg of milk per day with a fat and protein content of 4.0 and 3.4 %, respectively. Schwarz (2008) described a range of 14 to 24 kg dry matter intake per day as required for saturation and normally working digestive processes in dairy cows. On average, cows used for this study produced 41.6 kg of milk per day, containing 4.0 % fat and 3.3 % protein. Hence, determined dry matter intake lies within the regular limits.
It has been previously reported that cattle fed in a barn have an average number
of 12.1 meals per day (Vasilatos and Wangsness, 1980), or, according to Dado and
Allen (1994), around 11 feeding periods per day. Also, an average total feeding
time of 253.6 min d
The effect of the day of oestrus was significant for two of the investigated
parameters (“daily feed intake amount (kg)” and “time spent feeding per day
(min)”). Oestrus had a reducing effect on both parameters (10.3 and
20.8 %, respectively). In the study of Reith and Hoy (2012), rumination
time was related to oestrus in dairy cows. They determined rumination time
to be significantly reduced on the day of oestrus by 17.0 % (74 min d
“Daily milk yield (kg)” was not affected by oestrus but was characterized by high variation among all days of the oestrus cycle. In consideration of earlier studies, where milk yield was observed to be reduced at the first milking after onset of oestrus, followed by a rebound enhancement at the second milking (Horrell et al., 1985), significantly reduced on the day of oestrus (Schofield et al., 1991), or declined slightly from 1 day before oestrus until 2 days after oestrus (Lewis and Newman, 1984), a decline in milk yield on the days around oestrus could have been expected. In the current study, milk yield was slightly reduced 1 day after oestrus by 1.8 kg (4.1 %), followed by an increase of 3.3 kg (7.8 %) on day 2 after oestrus. Hence, results come close to the results found by Horrell et al. (1985).
Parity was investigated for its effects on all parameters except daily milk
yield (kg). It had a significant effect on all three parameters. When compared
to cows of higher lactations, cows of first lactation were characterized by a lower feed intake amount of 14.4 %
but a higher number of visits to the feeding trough (18.0 %) and a
longer time spent at the feeding trough per day (14.1 %). Similar results were found by Proudfoot et al. (2009), who also used the RIC system to investigate the effect of
competition (
The reducing effect of oestrus was more highly pronounced in multiparous cows than in primiparous cows in all three parameters. Nevertheless, Reith and Hoy (2012) found the decrease in rumination time to be more pronounced in primiparous cows than in older cows.
In conclusion, the results indicate that feed intake behaviour is influenced by oestrus. However, the condition for accurate monitoring of the required parameters is the installation of an RIC system. This prerequisite makes it difficult to use monitoring of feed intake behaviour as an auxiliary heat detection method to improve fertility management. Edited by: A.-E. Freifrau von Tiele-Winckler Reviewed by: two anonymous referees