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SURVIVAL ANALYSIS ON THE REPRODUCTIVE AND
PRODUCTION PERFORMANCES OF DAIRY COW IN BOGOR
Brian Rinaldy Irsyad, Bagus Priyo Purwanto, Epi Taufik
Institut Pertanian Bogor, Jawa Barat, Indonesia
Abstract
The aim of this study was to analyze the reproductive performance (empty period) and production (peak time of
milk production) of 87 dairy cows (Friesian Holstein) at X dairy farm Bogor using survival analysis. The analysis
results based on the Kaplan-Meier curve showed that the median total idle time, primiparous cow, multiparous
cow, cow that gave birth in the rainy and dry seasons were 210; 335; 231; 272; and 397 days. The median value
of the total peak milk production, primiparous cow, multiparous cow, cow that give birth in the rainy and dry
seasons is 41; 41; 39; 41; 41 days. The Cox Proportional Hazard regression results on idle time showed that the
multiparous cow was 1.84 times more likely (P<0.05) to have a shorter idle period than the primiparous cow.
Cows that gave birth during the rainy season had a 1.80 times shorter chance than cows that gave birth during the
dry season, although they were not statistically significantly different (P=0.043). The regression results on peak
milk production showed no difference between cows and primiparous cows. Meanwhile, cows that gave birth
during the rainy season experienced peak lactation 1.26 times and tended to be faster than cows that gave birth
during the dry season, although this was not statistically significant. The study's conclusions show that it was
necessary to improve the management of reproduction and production of X dairy farm in Bogor.
Keywords
: survival analysis; dairy cows; day in milk; days open; lactation number.
INTRODUCTION
The potential for increasing livestock business in Indonesia is very high. The livestock
sub-sector contributed 1.69% (260 189.6 billion rupiah) of Indonesia's total GDP (Gross
Domestic Product) in 2020 (BPS 202:1). The data has continued to increase since 2016 with
an average increase of 6% per year. This is a new challenge to realize a more efficient livestock
business.
Dairy cattle business is one of the livestock businesses with great potential to be
developed in Indonesia. The demand for cow's milk in Indonesia is high, it has not been met
by local farmers in Indonesia. The government implements an import policy to meet the needs
of cow's milk in Indonesia. Thus, it is necessary to study production efficiency so that the price
of cow's milk from local farmers can compete with imported cow's milk.
The efficiency of dairy farming can be determined by the fertility of the mother cow and
the milk yield produced. Some signs of good fertility are when adult heifers show clear signs
of lust, have a high chance of bunting when mated, and have a short lambing interval. One of
the management that is to increase efficiency is by improving the empty period and increasing
milk production.
The empty period is one of the measurements of fertility indicators in dairy livestock. A
short blank period will increase production efficiency. The empty period is influenced by
Injuruty: Interdiciplinary Journal and Humanity
Volume 2, Number 10, October 2023
e-ISSN: 2963-4113 and p-ISSN: 2963-3397
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several factors, including the length of the lactation period (Grossman and Koops 2003), the
lactation period Mitchell et al., (2005), the sex of the child born Córdova-Izquierdo et al.,
(2008), the level of milk production (Brotherstone et al. 2003), the season during lambing and
the age of the cow Oseni, Misztal, Tsuruta, & Rekaya, (2003). So that the empty period will
affect milk production in the next lactation.
The time change between the vacancy period and the previous production with the future
one is a critical factor in dairy farming. For this reason, it is necessary to analyze the empty
period and milk production. One analysis that can be used is survival analysis.
Survival analysis is a statistical procedure used to describe data related to time, from the
time of organization of a particular study, to the time of emergence of events or end points.
Events that occur can be recurrent events, new events, or responses from an experiment Collet,
2003; Kleinbaum & Klein, 1996; Muhajir & Palupi,(2018). The term survival analysis is often
associated with survival time, failed cases, censored data, hazard's function, life table, Kaplan-
Meier curve, and cox proportional hazard model (Taufik & Suriyasataphorn, 2008).
The cox proportional hazard model studies the occurrence of events in a certain time
span. The occurrence of the event is calculated based on the occurrence of the same event from
the initial time to a certain predetermined end time (Schneider et al., 2005). The length of time
used cannot be ascertained, because the event may have occurred before the time frame
specified when researching. The purpose of the cox proportional hazard model is to determine
the hazard ratio (RH) used to estimate the occurrence (in this study i.e. the plantation) at a given
value compared to the reference value. For example, if the deadlock in a particular event is >1,
then the value is higher than the reference value.
One of the main problems experienced by some farmers is low milk production and the
empty period of dairy cows that exceed the ideal limit. Córdova-Izquierdo et al., (2008) state
that the period of vacancy is 85-115 days after lambing. Ali et al., (2000) add that there is no
vacancy period of less than 30 days. The length of the normal empty period is 60 to 90 days,
and it is relatively normal when it is not more than 120 days.
Research on the empty period of dairy cows in Temanggung, Central Java resulted in an
empty period of 120-196 days Toharmat et al., (2007). While the research of Atabany et al.,
(2013) in Purwokerto, Central Java has an average blank period of 138 days. This shows that
the empty period of dairy cows in Indonesia is still relatively long.
When compared to the empty period of dairy cows in Thailand, the length of the empty
period shows no noticeable difference. Research by Taufik and Suriyasataphorn (2008) states
that the vacant period of 143 dairy cows from 6 farms in Northeastern Thailand resulted in a
median vacant period of 210 days. While Punyapornwithaya and Teepatimakorn (2004) in
Northern Thailand resulted in a median vacancy period of 131 days. However, research on
empty period and dairy cattle production with survival analysis in Indonesia has not been
widely conducted. Therefore, it is necessary to conduct research with a survival analysis study
of the influence of the season during lambing and lactation period on the empty period and
milk production to implement proper maintenance management.
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METHOD RESEARCH
Data Retrieval
Data was taken from production records of 87 lactation adult female dairy cows from
Farm X in Bogor Regency, West Java. The parameters observed were cow identity (IDS), last
lambing date (TBT), return bunting date (TBK), peak milk production (PPS), lactation period
(JLA), and indicators of bunting or occurrence (1 = bunting; 0 = no bunting). Data is processed
using Microsoft Excel. The data collection is used to identify vacancy and milk production for:
Lactation period: Primiparous (mother cow that has partus once) and multiparous
(mother cow that has partus more than once) (Feliciano et al. 2003); Season when giving birth:
dry and rainy.
Analysis and Data Variables
This study used a cox proportional hazard model to analyze the effect of season during
lambing, lactation period on empty period and milk production. All data analysis uses Statistix
10.0 software.
This study used three variables: independent variables, dependent variables, and
censored variables. The dependent factors in this study are the length of time (survival time),
empty period and peak time of milk production production. The independent variables in this
study were the season (dry or rainy) and the lactation period of cows (first lactation and more
than one lactation). The censored variable is the number of cows that came out at the time of
observation due to fall, death, or slaughter.
RESULT AND DISCUSSION
Kaplan Meier Curve and the Ratio of Empty Period to Lactation Hazard
The empty period or open days is the distance between lambing until pregnancy occurs
or the days from after lambing to pregnancy. According to Warwick & Legates, (1979), the
recommended vacancy period for lactation heifers is 90 days and for lactation mother cows for
60 – 90 days. The empty period in that time span, it is expected that the mother cow can produce
high enough milk at the end of lactation. But the shorter the empty period can also reduce
production in lactation. This can occur due to udder gland regression caused by competition
for the use of nutrients for fetal development (Brotherstone et al., 2004).
An optimal blank period is necessary to achieve milk production efficiency. Weller et al.
Research states that, the optimal empty period is at 110 - 130 days. Cows that have an empty
period of less than 60 days will decrease the total milk yield per year, both in walking lactation
and subsequent lactation. While cows that have too long an empty period, will decrease milk
production during productive life because it will decrease the frequency of births as the
beginning of a new lactation process (Warwick & Legates, 1979).
Maintenance management is one of the factors that can regulate the vacancy period in
dairy cows. Conventional rearing management uses a lambing interval of 12 months, so that
births can occur every year and are able to produce milk optimally Schmidt & Van Vleck,
1974; Warwick & Legates, (1979). Nevertheless, rearing management in sow cows with high
milk yield tends to delay the lambing interval by up to 15 months. Postponement of the lambing
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interval aims to reduce the risk of mastitis and other metabolic symptoms (Rehn et al., 2000)..
This certainly affects the empty period of dairy cows during rearing.
Figure 1 Kaplan-Meier curve survival time of the entire empty period (days) of the
mother cow at farm X in Bogor
The Kaplan-Meier curve of the overall survival time of cow blanks is shown in Figure 1.
Based on the curve, overall the mother cow at farm X Bogor produced a median of 274 days.
This is higher when compared to the study of Taufik and Suriyasataphorn (2008) in
Northeastern Thai people's farms which yielded a median of 210 days, while the research of
Punyapornwithaya & Teepatimakorn, (2004) in Northern Thailand resulted in a median of 131
days.
The empty period of dairy cows in Indonesia is long when compared to other countries.
Research by Iswati et al., (2020) resulted in a vacant period of 117.10 days of dairy cows in
the cattle herd of Tegalombo District, Pacitan, East Java. Vacant period research by Anggraeni
et al., (2014) resulted in a blank period of 66.9 - 215.3 days at BPPT SP Cikole, Lembang,
West Java. Meanwhile, the vacant period research at BPPT Baturraden, Central Java resulted
in an average empty period of 149 days Anggraeni et al., (2014) and 152.9±39.3 days with a
range of 114 - 192 days (Abdallah, 2020).
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Figure 2 Curve of average milk production (liters) in Farm X Bogor
Figure 2 shows Farm X Bogor's daily milk production which is high at the beginning of
production and tends to be stable after 305 days of milk production. Cows with high milk yield,
secrete a high hormone prolactin. The secretion of the hormone prolactin can inhibit the
hormone gonadotropin, so it can cause a delay in lust. This is in accordance with the statement
Atabany et al., (2013) that cows that have high production at the beginning of lactation, have a
longer empty period and have the potential to experience delays in lust.
Other factors that can extend the vacancy period of dairy cows include maintenance
management factors. A longer vacancy period can maximize annual milk yield. Research
Anggraeni et al., (2014) stated that the extension of the vacancy period of about 60 days
provided additional milk production from 3639 kg to 5119 kg at BPTU Baturaden and provided
an additional from 2782 kg to 3189 kg in assisted community farms. Anggraeni et al. (2010)
also added, compared to milk production from an empty period of 60 days, extending the empty
period to 200 days can increase milk production by up to 18%.
Figure 3 Kaplan-Meier curve survival time empty period (days) to lactation period
(1=multiparous; 0=primiparous).
Primiparous cows experience a longer empty period than multiparous cows. Based on
figure 3, the Kaplan-Meier curve of empty period survival time with events (bunting or not
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bunting) to lactation yields a median of 335 days for primiparous cows, and 231 days for
multiparous cows. The median of cows by lactation period showed markedly different results
(P = 0.0476). This shows that multiparous cows markedly have a shorter vacancy period.
When compared to the research of Taufik and Suriyasataphorn (2008), the median result
resulted in higher data. The research of Taufik and Suriyasataphorn (2008) resulted in a median
of 226 days for primiparous cows, and 207 days for multiparous cows. Nevertheless, the
results show the equation that the median vacancy period in multiparous cows is shorter than
in primiparous cows.
Table 1 1Cox Proportional Hazard Model vacant period at Farm X Bogor
Variable
ONE
P
Hazard Ratio
Lactation period
Lactation 1
-0.61246
0.30198
0.0476
0.54
Lactation >1
0.61246
0.30918
0.0476
1.84
Remarks : = coefficient; SE = default error
The results of the analysis of data from the Cox Proportional Hazard model of cow
vacancy against lactation period are shown in table 1. The results of the analysis showed clearly
(P<0.05) that multiparous cows were 1.84 times more likely to experience a shorter empty
period than primiparous cows. The results of this study are in accordance with research
conducted by Taufik and Suriyasataphorn (2008) and research by Punyapornwithaya and
Teepatimakorn (2004) which states that multiparous cows have the opportunity to experience
a shorter empty period than primiparous cows.
Research by Hadisutanto and Parera (2014) states that in fact multiparous cows
experience a shorter empty period than primiparous cows. This is because primiparous cows
are higher in using food substances for their body growth which has only reached 82-90% for
3 weeks before partus and 3 weeks after partus. Multiparous cows are more efficient than
primiparous cows, because multiparous cows have mature cells and hormonal systems so they
are better prepared to reproduce (Anggraeni et al. 2010). Ismail (2009) adds that the lust of
primiparous cows is more difficult to detect than multiparous cows.
Kaplan Meier Curve and the Hazard Ratio of Empty Time to Lambing Season
The majority of dairy cows from Peternakan X Bogor give birth in the rainy season.
Based on figure 4, Bogor X Farm is in area 72. The region experiences a rainy season in late
August to early June of the following year. Region 72 is the area with the longest rainfall when
compared to other regions in West Java Province, which is for 290 days with rainfall of 3360
mm / year (BMKG 2021).
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Figure 4 The beginning of the rainy season in West Java Province (Source: BMKG,
2021)
Figure 5 Kaplan-Meier curve survival time of empty period (days) against lambing
season (1=rain; 0=drought)
Cows that give birth in the rainy season, tend to experience an empty period faster than
cows that give birth in the dry season. Based on figure 5, the Kaplan-Meier curve of empty
period survival time to events (bunting or not bunting) to the lambing season, yields a median
of 272 days for cows that lamb in the rainy season, and 397 days for cows that give birth in
the dry season. The median showed no noticeable difference (P = 0.2194). The results are
higher when compared to the research of Taufik and Suriyasataphorn (2008) which resulted in
a median of 231 days in summer and 204 days in other seasons (cold and rainy) in Thailand.
However, these results show the equation that the median vacancy period of cows that lamb in
the rain/winter season is shorter than in the dry/hot season.
Table 2 2Cox Proportional Hazard Model of vacant period at Farm X Bogor
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Variable
ONE
P
Hazard Ratio
Birth season
Rain
0.58976
0.48024
0.2194
1.80
Dry season
-0.58976
0.48024
0.2194
0.55
Remarks : = coefficient; SE = default error
The results of data analysis of the Cox Proportional Hazard model of cow vacancy
against the birth season are shown in table 2. Cows that give birth in the rainy season are 1.80
times more likely to experience a shorter vacancy period than cows that give birth in the dry
month even though the results are not statistically real (P = 0.2194). These results are in
accordance with the research of Taufik and Suriyasataphorn (2008) which states that cows born
in the rainy and winter seasons have a greater chance than cows born in the dry season.
Seasonal conditions can affect the reproductive performance of dairy cows. Research
Farin et al. (1994) states that cows that give birth in the summer are less likely to get pregnant
than cows that give birth in the colder season. Cows that give birth in the dry season, will
experience heat stress, so the efficiency of energy use will be reduced due to increased energy
for basic living and thermoregulation activities. Insufficient feed intake can interfere with the
synthesis and regulation of reproductive hormones that play a role in the appearance of lust
symptoms (Abidin et al. 2012).
Kaplan-Meier Curve and Hazard Ratio of Peak Milk Production to Lactation Period
Dairy farming business will provide a good level of production efficiency if the mother
cows raised are able to convert feed into milk production efficiently. Production efficiency can
be determined by the persistence of milk production after reaching peak production. Anggraeni
et al. (2000) states that environmental factors greatly influence the daily milk production
curve. Factors that can affect milk production include the lactation period (Mitchell et al.
2005) and the season of lambing (Oseni et al. 2013).
Figure 6 Kaplan-Meier curve survival time of peak milk production (day -) of all mother
cows at farm X in Bogor
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Figure 7 Kaplan-Meier curve survival time of peak milk production (day -) to lactation
period (1=multiparous; 0=primiparous).
The Kaplan-Meier curve of peak survival time of overall milk production is shown in
Figure 6. Based on the curve, the peak day of milk production of mother cows at farm X Bogor
yielded a median of 41 days.
Based on Figure 7, primiparous cows tend to reach peak milk yield faster than
multiparous cows . This is indicated by the Kaplan-Meier curve of peak milk production
survival time with events (bunting or not bunting) to lactation resulting in a median of 41 days
for primiparous cows and 39 days for multiparous cows. Rahman et al. (2015) in UPBS
Pangalengan which states that multiparous cows reach peak milk production days faster than
primiparous cows. Atashi et al. (2009) states that the average peak milk production is reached
on the 49th day after partus. While Fadlemoula et al. (2007) states the peak of cow's milk
production occurs on the 64th day. Nevertheless, the median cow by lactation period showed
no markedly different results (P = 0.7367).
Table 3 3Cox Proportional Hazard Model of peak milk production in Farm X Bogor
Variable
ONE
P
Hazard Ratio
Lactation period
Lactation 1
-0.09794
0.29074
0.7362
0.91
Lactation >1
0.09794
0.29074
0.7362
1.10
Remarks : = coefficient; SE = default error
Table 3 shows the results of data analysis of the Cox Proportional Hazard model of peak
cow milk production according to lactation period. The results of the analysis showed that the
lactation period had no real effect (P = 0.7362) on the peak of cow's milk production. Research
by Rao and Sundaresan (19, 81) states that the udder glands of primiparous cows take longer
to reach peak milk production than multiparous cows.
Kaplan-Meier Curve and Hazard Ratio of Peak Milk Production to Lambing Season
The shape of the milk production curve is influenced by the time of peak milk production,
the level of milk production, and the rate of decline in milk production after reaching peak
production. The peak time of milk production can be reached when the cow has undergone
uterine involution, 40 to 60 days post partus (Atabany et al. 2013).
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Figure 8 Kaplan-Meier curve survival time of peak milk production (day-) to lambing
season (1=rain; 0=drought)
The Kaplan-Meier curve of peak milk production survival time with events (bunting or
not bunting) with lambing seasons, yields a median of 40.5 days for cows that lamb in the rainy
season and 40.8 days for cows that lamb in the dry season. The median showed no noticeable
difference (P = 0.4325).
Table 4 4Cox Proportional Hazard Model of peak milk production in Farm X Bogor
Variable
ONE
P
Hazard Ratio
Birth season
Rain
0.23052
0.29593
0.4360
1.26
Dry season
-0.23052
0.29593
0.4360
0.79
Remarks : = coefficient; SE = default error
Table 4 shows the results of data analysis of the Cox Proportional Hazard model of peak
cow milk production according to the season at lambing. The results of the analysis showed
that the season during lambing had no real effect (P = 0.4360) on the peak of cow's milk
production. Cows that lamb in the rainy season, reach the peak of lactation 1.26 times tend to
be faster than cows that give birth in the dry season, although statistically it is not significantly
different. This is in accordance with the research of Anggraeni et al. (2000) which states that
seasons have no noticeable influence on the daily milk yield curve.
The achievement of a faster peak milk production period (primiparous cows and lambing
cows in the rainy season) at Farm X Bogor showed poor performance. Cows that reach peak
milk yield faster will decline faster until day 301 (Atabany et al. 2013; Dekkers et al. 1998).
The peak period of milk production is influenced by the ability of aveolar cells and the comfort
of the surrounding environment. Cows that lamb in the rainy season experience high humidity
stress, which causes cows discomfort.
CONCLUSION
The results showed that the empty period of multiparous cows is shorter than that of
primiparous cows. The empty period of cows that give birth in the rainy season is shorter than
cows that give birth in the dry season, although it is not statistically different. The time to reach
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the peak of milk yield of multiparous and primiparous cows shows no difference. Cows that
give birth in the rainy season tend to reach the peak of milk production less than cows that give
birth in the dry season, although statistically it does not differ markedly.
The results of the analysis show that it is necessary to evaluate reproductive and
production management in Bogor X dairy farm in order to improve the efficiency of
reproductive and production performance.
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Copyright holders:
Brian Rinaldy Irsyad, Bagus Priyo Purwanto, Epi Taufik (2023)
First publication right:
Injurity - Interdiciplinary Journal and Humanity
This article is licensed under a Creative Commons Attribution-ShareAlike 4.0
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