Milk production and composition in Danish Holstein, Danish Red, and Danish Jersey cows supplemented with saturated or unsaturated fat

Livestock Science 155 (2013) 60–70

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Milk production and composition in Danish Holstein, Danish Red, and Danish Jersey cows supplemented with saturated or unsaturated fat Martin Riis Weisbjerg a,n, Mette Krogh Larsen b, Lone Hymøller a, Mette Thorhauge a, Ulla Kidmose b, Jacob Holm Nielsen b,1, Jens Bech Andersen a a b

Department of Animal Science, Aarhus University, AU Foulum, DK-8830 Tjele, Denmark Department of Food Science, Aarhus University, Denmark

a r t i c l e in f o

abstract

Article history: Received 14 March 2012 Received in revised form 10 April 2013 Accepted 11 April 2013

The aim of the experiment was to study the response in milk production and composition of substituting barley with either saturated or unsaturated fat in mixed rations (MR) for dairy cows. The experiment included 35 Danish Holstein (DH), 39 Danish Red (DR), and 31 Danish Jersey (DJ) cows from parturition until week 30 of lactation. Cows were ad libitum fed one of the three MR based on maize and grass/clover silage, barley, soybean meal, and dried sugar beet pulp. In the saturated ration (SFA), C16 rich fat substituted barley on dry matter (DM) basis; in the unsaturated ration (UFA), ground rape and linseed (0.74:0.26 ratio) substituted barley on DM basis; and in the control ration (CO), no barley was substituted. Concentrations of crude fat (CF) of total ration DM was 3.03% in CO, and in diets supplemented to intended similar fat levels 5.65% (SFA) and 5.81% (UFA), respectively. Statistical analyses were performed within breed and random regression was used to test for differences between treatment responses throughout lactations. For all breeds, SFA increased milk fat concentration of C16 whereas UFA increased milk fat concentration of unsaturated as well as saturated C18 fatty acids (FA). For each of the three breeds the following responses were obtained compared to CO. DR: UFA increased the net energy intake (NEI) (P ¼0.04), but energy corrected milk (ECM) yield was reduced to 30.9 kg/d compared to 31.7 kg/d for CO (ns). SFA increased milk fat concentration to 4.42% compared to 3.87% for CO (Po 0.0001). DH: SFA decreased DM intake (DMI) (P ¼ 0.05), but ECM was slightly increased to 34.5 kg/d compared to 34.0 kg/d for CO (ns). Both SFA and UFA decreased the milk protein concentration to 3.30% compared to 3.49% for CO (Po 0.05). Sensory analysis of milk from DH showed only minor differences between treatments. DJ: SFA (P¼ 0.2) and UFA (P¼ 0.07) tended to decrease DMI, and decreased ECM to 28.6 kg/d (SFA, P ¼ 0.02) and 28.0 kg/d (UFA, P ¼ 0.01) compared to 31.6 kg/d (CO). Furthermore, SFA and UFA tended to increase milk fat. In conclusion, SFA caused a lower protein:fat ratio in milk for all breeds, while UFA only reduced protein:fat ratio for DJ. The minor increased (DH), and the tendency to decreased (DR, DJ) milk yield response to feeding SFA was unexpected, and may be due to a general negative effect of feeding fat in early lactation. & 2013 Elsevier B.V. All rights reserved.

Keywords: Linseed Rapeseed Milk composition Milk fatty acids Sensory analysis

1. Introduction n

Corresponding author. Tel.: +45 8715 8046; fax: +45 8745 4249. E-mail address: [email protected] (M.R. Weisbjerg). 1 Current address: Department of Food Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark. 1871-1413/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.livsci.2013.04.008

With the expectation of an increased production response, dietary fat is used for dairy cows in order to

M.R. Weisbjerg et al. / Livestock Science 155 (2013) 60–70

diminish the gap between net energy intake (NEI) and requirements to high milk yield (MY) and maintenance. Furthermore, uses of supplementary fat to manipulate milk fatty acid (FA) profiles (Larsen et al., 2012a) and reduce methane excretions (Beauchemin et al., 2007), has gained interest. Traditionally, fat sources with an iodine value of about 80 have been the main fat sources in dairy cow production experiments. Supplementing cows with fat sources of a lower iodine value e.g. saturated or protected fat often increases production responses such as MY (Chilliard, 1993). Moreover it is possible to increase the concentration of these fat sources in ration dry matter (DM), as they are inert in the rumen (Doreau and Chilliard, 1997). Supplementing cows with fat sources of higher iodine values, e.g. oilseeds, is often done to manipulate milk FA composition and make it more desirable for the food industry and consumption by humans (Grummer, 1991; Larsen et al., 2012a). However, fat may have a negative effect on the rumen due to toxic effects on mainly protozoa but also cellulolytic bacteria (Jenkins, 1993). However, the magnitude of the negative effect is determined by the physical form of the fat source e.g. oils have a more negative effect on the rumen than oilseeds and cakes, probably due to lack of physical protection (Chilliard et al., 2009; Hurtaud et al., 2010; Jenkins, 1993). Manipulating the FA composition of milk may affect sensory properties, especially a higher amount of unsaturated fat would make the milk more susceptible to oxidation which may give a metallic or cardboard-like offflavour and high amounts of saturated C16 may give a roquefort-like off-flavour due to lipolysis (Hedegaard et al., 2006). Due to the difference between breeds in de novo synthesis of milk fatty acids, where especially Jersey deviate with a high milk fat content and a high de novo synthesis, makes it plausible that breeds would respond different on fat supplementation. It was hypothesised that supplementation with saturated fat should increase production of energy corrected fat substantially, whereas supplementation with similar fat amounts as unsaturated oilseed fat would affect milk production less, however increase milk linolenic acid concentration. The aim of this experiment was to study the response on feed intake (FI), MY, and milk composition to feeding dairy cows of three different breeds two extreme fat sources in mixed rations (MR) during week 1–30 (W1−30) of lactation in a loose housing system with automatic milking. 2. Materials and methods 2.1. Animals and experimental design Animal experiments complied with the Danish Ministry of Justice Law no. 726 (September 9, 1993) concerning experiments with animals and care of experimental animals. The study was carried out between January 2007 and January 2008 and included 112 lactations of which 105 were used for statistical analysis. The study included 35 (11 CO, 12 SFA and 12 UFA) Danish Holstein (DH), 39 (13 CO, 15 SFA and 11 UFA) Danish Red (DR), and 31 (11 CO, 11 SFA and 9 UFA)

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Danish Jersey (DJ) cows from parturition until week 30 of lactation. Each breed was divided into two genetic lines, one bred for high milk yield and one bred for good health and longevity, respectively. The cows calved between 1st of January and 1st of August 2007. At calving animals were randomly assigned to one of the three experimental feed treatments in a randomised block design within breed, parity (first and older), and genetic line. The cows participated in the study during either the entire lactation period or until January 2008 or culled. Out of cows started, 73 fulfilled 20 weeks, and 51 fulfilled 30 weeks. 2.2. Feed Rations were formulated according to Danish recommendations (Strudsholm et al., 1999). During the dry period, all cows in the experiment were fed the same standard MR ad libitum. The ration contained 35% grass/ clover silage, 28% maize silage, 25% spring barley straw, 6% concentrate, 5% soya bean meal, and 1% NaCl, urea, minerals, and vitamins (DM basis). During lactation cows were assigned to one of three different MR, which were fed ad libitum: a MR containing protected, saturated fat (SFA), a MR containing unsaturated fat (UFA) or a control MR (CO). SFA contained Lipitec Bovi 80 (NLM Vantinge ApS, Ringe, Denmark) with 498% crude fat in DM,4 80% C16:0, 10% C18:1, and 6% C18:0. UFA contained ground rape- (48% crude fat in DM) and linseed (45% crude fat in DM) in a 0.74:0.26 ratio to secure a high content of C18:1 and C18:3 from a fat source which was useful under practical feeding conditions. The oilseeds were ground between smooth rolls on a roller from Mortensens Mølle-Maskinfabrik (Holstebro, Denmark). CO was not supplemented with extra fat. The fat source in the SFA and UFA rations substituted barley on DM basis. Table 1 shows the composition of ingredients and nutrients of the three MR. The cows had ad libitum access to water. Cows were offered one kg/d of concentrate (chemical composition in % of DM: ash 7.8; crude protein 22.7; crude fat 4.9; NDF 32.6; starch 10.7; sugar 8.1, sugar 8.1) in an automatic milking unit (AMU) postpartum, increasing with 250 g/d until the cows reached 4 kg/d. 2.3. Housing and management Experiments were carried out at the Danish Cattle Research Centre (DCRC) with a herd of 150 dairy cows. Cows were kept in a loose–housing system with slatted floors and cubicles with mattresses. A free cow–traffic system was applied for access to an automatic milking system (AMS) from DeLaval AB (Tumba, Sweden). Within the dairy unit, cows were organised in three groups (AMSgroups), one with DJ cows and two with mixed DH and DR cows. Each group had access to one AMU equipped with a device for automatic measurement of MY and milk sampling. Additionally the AMUs were equipped with a device for concentrate feeding and weighing of concentrate refusals at the end of each cow visit. For automatic recording of individual cows' MR intake the Insentec RIC system (Marknesse, the Netherlands) with mangers on scales and individual cow registration was used. The

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M.R. Weisbjerg et al. / Livestock Science 155 (2013) 60–70

Table 1 Ingredients of mixed rations (g/kg DM) and measured nutrient composition (% DM) from the three dietary treatments: control ration (CO), saturated ration (SFA), unsaturated ration (UFA).

Mixed ration Grass/clover silage Maize silage Sugar beet pulp, dried Soya bean meal Barleya Lipitec Bovi 80b Rapeseedc Linseedd Minerals and vitamins Urea Chemical composition Crude fat Protein NDF Starch Sugar Ash Crude fibre NELe (MJ/kg DM)

CO

SFA

UFA

344 344 94 125 73

344 344 94 125 40 33

344 344 94 125

18 2

18 2

3.03 18.3 33.0 14.9 5.10 7.84 17.0 7.73

5.65 17.9 32.8 12.9 4.98 7.73 17.1 8.05

56 19 18

3.03 18.3 33.0 14.9 5.10 7.84 17.0 7.73

a FA content (g/kg DM): C16:0 7.0; C18:1 3.4; C18:2 16.0; C18:3 1.7; ΣFA 28.8. b Lipitec Bovi 80 (NLM Combinering ApS, Vantinge, Denmark), FA content (g/kg DM): C16:0 805.1; C18:1 35.3; C18:2 8.5; C18:3 0.3; ΣFA 860.8. c FA content (g/kg DM): C16:0 21.6; C18:1 263.0; C18:2 84.1; C18:3 44.8; ΣFA 423.0. d FA content (g/kg DM): C16:0 21.8; C18:1 74.4; C18:2 66.5; C18:3 227.8; ΣFA 406.6. e Net energy for lactation.

facilities and management procedures at DCRC are described in detail by Bossen and Weisbjerg (2009) and Bossen et al. (2009). 2.4. Data collection Information on MR intake, concentrate intake, MY, and milk composition was obtained as described by Bossen and Weisbjerg (2009) and Bossen et al. (2009). Energy Corrected Milk (ECM) was calculated as described by Sjaunja et al. (1991). 2.5. Laboratory analyses 2.5.1. Feed Chemical analyses of individual feedstuffs and adjustment of feed rations during the study were carried out as described by Bossen et al. (2009). Feed FA were extracted and methylated as described by Palmquist and Jenkins (2003) followed by gas chromatographic analysis as described by Larsen et al. (2011) using C17 triglyceride as internal standard. 2.5.2. Milk FA analysis For each treatment (CO, SFA, UFA) cows which calved within the same 15 week period were selected for analysis of milk FA composition. Milk was sampled on one day in lactation weeks 871; 20 72; and 30 72. Milk was

sampled from one milking as FA composition does not vary between individual milkings (Larsen et al., 2012b). Milk samples were frozen on the day of sampling and stored at −20 1C until analysis. Milk FA composition was analysed as described by Larsen et al. (2011). For milk as well as feed samples FA methyl esters were identified by use of external standards (Supelco 37 component FAME mix from Supelco, Bellafonte, PA, USA and GLC 469 methyl ester standard from NU-CHek Prep Inc, Elysian, MN, USA. 2.5.3. Sensory analysis Only milk from DH cows was used for sensory analysis. All milk from one milking of at least three cows (in lactation week 2075) from each treatment group was pooled, pasteurised (72 1C, 15 s), cooled and stored at 3 72 1C until analysis the subsequent day. Four triangle tests were conducted where two of the three samples were similar and one was different. The assessors had to designate which sample was different (Meilgaard et al., 2007). In two triangle tests carried out on different days CO samples were compared to UFA samples under normal light. In the other two triangle tests carried out on a third day CO samples were compared to SFA or UFA samples, respectively, under red light to mask differences in appearance. The triangle tests were performed by 27–30 trained assessors. In addition, a trained sensory panel of 10 assessors evaluated the UFA, SFA and CO milk samples using a sensory quantitative descriptive analysis (QDA). Prior to the sensory evaluation the sensory panel was trained using samples that differ significantly and reference samples. The assessors developed a sensory profile for the milk samples, which included three aroma descriptors, nine flavour and taste descriptors as well as three descriptors related to the appearance and viscosity. The attributes were evaluated on a continuous scale where zero corresponded to the lowest intensity and 15 corresponded to the highest intensity. The samples were evaluated in three replicates. All milk samples were served at 16 72 1C. 2.6. Statistics and calculations The ECM yield was defined per day calculated from weekly averages. The feed conversion efficiency (FCE) was calculated as the sum of energy required for maintenance and milk production (Strudsholm et al., 1999) divided by the net energy value of the FI. Statistical analysis was performed in SAS 9.2 using the mixed procedure (Littell et al., 2006). The response of cow l from treatment group i, parity j, genetic line k in the lactation week t was given by the regression model: yijklt ¼ μ þ tr i þ paj þ lik þ tr  paij þ tr  liik þ pa  lijk þγ  cwl þ col þ ðβ1i þ b1l Þ  X 1ijklt þ ðβ2i þ b2l Þ X 2ijklt þ ðβ3i þ b3l Þ  X 3ijklt þ ðβ4i þ b4l Þ  X 4ijklt þ eijklt

The fixed effects were tr¼treatment; Pa¼Parity; li¼ genetic line; and interactions. co¼cow and the covariate cw¼calving weight. Time t¼number of weeks in lactation for cow l. The identical independent distributed random residual effects were denoted eijklt iid Nð0; s2 Þ. β1−4 and

M.R. Weisbjerg et al. / Livestock Science 155 (2013) 60–70

γ¼regression coefficients. X1ijklt−4ijklt ¼covariates, where X1ijklt ¼ t/30, X2ijklt ¼(t/30)2, X3ijklt ¼ln(30/t), X4ijklt ¼(ln(30/t))2 (Ali and Schaeffer, 1987). b1−4l ¼random coefficients for each cow l. An unstructured (un) covariance structure was used. In situations of no convergence a simpler diagonal matrix (Σ¼vc) was used. The difference between the responses to the treatment groups from W1−10, W11−20, and W21−30 was calculated as linear combinations of the fixed regression coefficients. This made it possible to test the treatment groups in three sub-periods of the lactation and for the whole period of 30 weeks. Preliminary analysis indicated different responses for different breeds, therefore each breed was analysed separately. The given estimates are Least Square Means (LSM) for W1−30 and standard error (SE). Effects with 0.05oPo0.2 are characterised as tendencies. Peak yield, week of peak yield, and persistency (slope after peak yield) was calculated using the same principles as previously described. Effect of genetic line is not reported, as it generally did not interact with treatment. Statistical analysis of milk FA composition, and of sensory QDA was carried out separately for each breed as a one-way anova with fixed effects of treatment. For sensory triangle tests the number of correct answers was tested against a binomial distribution where the probability of a correct guess is 1/3. 3. Results 3.1. Feed intake DR: There was no difference between treatments in concentrate or MR intake (Table 2). The NEI from the MR was higher for UFA compared with CO (P¼0.04) and tended to be higher for SFA (P ¼0.1) in W21−30, which resulted in a higher total DMI and NEI (Fig. 1A and D). DH: Feeding SFA tended to decrease the intake of concentrate (P ¼0.2) compared to CO during W1−30. Cows fed SFA had the lowest intake of MR during W1−10 compared to both UFA (P ¼0.01) and CO (P¼ 0.009), and during W11−20 compared to CO (P ¼0.05) (Fig. 1B and E). DJ: Concentrate intake was not affected by dietary treatment. The reduced daily intake of both concentrate and MR for cows fed SFA or UFA resulted in a numerically lower total daily DMI (UFA, P ¼0.07; SFA, P ¼0.2) and NEI compared with CO (Fig. 1C and F). 3.2. Milk yield and composition DR: Effects on milk production and composition, and AMU visiting behaviour of feeding with SFA or UFA are show in Table 3. ECM was numerically lower for cows fed SFA or UFA compared with CO. Peak MY was not affected by treatment. However, the stage of lactation where the peak yield occurred, tended to be affected by treatment (P ¼0.06). Cows fed CO reached peak yield in W5, followed by SFA in W6, and UFA in W8. Cows fed UFA were the most persistent, followed by cows on CO, which both had the same MY level in W30. Cows fed SFA were less persistent, which resulted in a lower MY than UFA and CO in W30 (Fig. 2A).

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Table 2 Mean effects (kg DM/d) of feeding control ration (CO), ration with saturated ration (SFA) or unsaturated ration (UFA) fat on feed intake and efficiency for Danish Red (DR), Danish Holstein (DH), and Danish Jersey during W1−30 of lactation. Least square mean (LSM) and standard error (SE). CO

SFA

UFA

LSM

SE

LSM

SE

LSM

SE

DR Concentratea Mixed ration Total DMIb

2.54 17.2 20.0

0.18 0.5 0.5

2.53 17.0 19.7

0.16 0.5 0.4

2.57 17.5 20.3

0.15 0.4 0.4

DH Concentratea Mixed ration Total DMIb

2.91 19.5b 22.5b

0.10 0.4 0.4

2.72 18.4a 21.0a

0.11 0.4 0.4

2.75 19.1ab 21.8ab

0.10 0.4 0.4

DJ Concentratea Mixed ration Total DMIb

3.06 15.3 18.5

0.12 0.5 0.5

2.96 14.5 17.5

0.12 0.5 0.6

2.79 14.4 17.1

0.11 0.5 0.5

Different indexes indicate significantly different results within rows (Po 0.05). a Dry matter. b Dry matter intake.

Milk fat concentration increased when feeding cows the SFA diet compared with the UFA diet (P¼0.0002) and the CO diet (P o0.0001) during W1−30 (Fig. 2D). Fat production was not affected by dietary treatment. Lactose concentration in milk from cows fed SFA was lower (P¼0.04) than cows fed UFA in W1−30 (Table 3). Citrate concentration decreased when cows were fed SFA (P ¼0.008) compared with UFA in W1−30. DH: MY and ECM did not respond to feeding SFA or UFA (Fig. 2B). Cows fed SFA were more persistent than cows fed UFA or CO and therefore had a higher yield in W30 (Fig. 2B). Fat concentration tended to be lower for cows fed UFA compared with SFA (W1−10, P ¼0.2; W11−20, P ¼0.1) and CO (W11−20, P ¼0.09; W21−30, P¼0.08) (Table 3). Milk protein concentration was lower on SFA (P ¼0.01) and UFA (P ¼0.008) compared with CO in W1−30 (Table 3). Lactose concentration was lower (P¼0.04) when cows were fed SFA compared with CO in W1-30 (Fig. 3B). Citrate concentration tended to increase when feeding SFA (P ¼0.2) or UFA (P ¼0.1) compared with CO in W1−30. Feeding UFA decreased daily frequency of complete milkings compared with CO (P ¼0.03) in W1−10. Number of daily rejections were reduced, when cows were fed SFA (P ¼0.009) or UFA (P¼ 0.001) compared with CO in W1−30 (data not shown). DJ: MY and ECM responded negatively to feeding SFA or UFA during W1−30, but especially in W1−10, where the reduction was more than six kg/d milk (SFA, P¼0.02; UFA, P ¼0.01) compared with CO (Fig. 2C). ECM and MY were affected (ECM, P¼ 0.009; MY, P ¼0.04) by dietary treatment already in W1, where cows fed SFA or UFA had a yield of about 3 kg ECM/d less than CO. MY was lower on SFA (P¼0.04) and UFA (P¼0.09) compared with CO in W1−30 (Table 3).

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M.R. Weisbjerg et al. / Livestock Science 155 (2013) 60–70

Total DMI, kg/d

DR

DH 25

25

20

20

20

15

15

15

10

10 0

10

20

10 0

30

10

20

30

0

Lactation week

Lactation week

Total energy intake, Fuc/d

DJ

25

25

25

20

20

20

15

15

15

10 0

10

20

Lactation week

30

20

30

Lactation week

25

10

10

10 0

10

20

30

Lactation week

0

10

20

30

Lactation week

Fig. 1. Mean daily dry matter (DM) intake and net energy intake (NEI) in Danish Red (DR), Danish Holstein (DH), and Danish Jersey (DJ), when fed saturated ration (SFA) (dotted line), unsaturated ration (UFA) (thin line), or control ration (CO) (bold line) during week 1–30 of lactation.

Feeding SFA or UFA decreased peak yield with about 6 kg/d (P ¼0.01). The stage of lactation where the peak yield occurred tended to be affected by treatment (P¼0.06). Peak yield occurred in W4 for cows fed SFA, followed by CO in W5, and UFA in W7. Cows fed UFA were more persistent compared with SFA or CO (Fig. 2C). The lactation curve of cows fed the CO diet had the steepest decrease but was at the same level as cows fed UFA in W30. The lactation curve for cows on SFA had the lowest peak yield and also had a lower MY than CO and UFA in W30. Efficiency decreased when SFA or UFA was fed (SFA, P ¼0.05; UFA, P ¼0.07) compared with CO in W1−10. Cows fed UFA had a higher efficiency (P ¼0.05) than cows fed SFA in W21−30. Feeding SFA increased milk fat concentration compared with CO in W1−20 (Po0.04). Feeding SFA or UFA decreased (P ¼0.03) milk protein production compared with CO ration during W1−30, whereas there was no effect of dietary treatment on protein concentration (Table 3). Milk lactose concentration was not affected by dietary treatment but milk lactose production decreased when feeding SFA (P¼0.04) or UFA (P¼0.02) compared with CO diet in W1−10. Citrate concentration was not affected by dietary treatment (Fig. 3F). 3.2.1. Milk fatty acid composition The FA composition of milk fat as affected by treatment for each breed is shown in Table 4. Compared to CO the milk fat content of C16 was higher when feeding SFA and lower when UFA was fed. In general the content of C18 FA was higher when UFA was fed whereas there was no difference between SFA and CO. For DJ the milk fat content of C18:0 was lower with the SFA treatment than CO and for DH the milk fat content of C18:1 cis9 was higher at the SFA compared to CO. For DR no differences in the milk fat content of C18:2 n6 were observed, for DH the content increased at the UFA treatment, whereas the content decreased at the UFA treatment of DJ. For C4–C14 FA

breeds responded differently to treatments: For DR both fat supplements decreased milk fat content of C4–C14, for DH the SFA treatment decreased milk fat content of C4–C14, and for DJ the UFA treatment decreased milk fat content of C4–C14. 3.2.2. Milk sensory properties As seen in Table 5 only the two first triangle tests that compared UFA with CO in light showed significant difference. However, the quantitative descriptive analysis did not show any significant differences in the sensory attributes, which were evaluated, which showed that that other parameters were used in the triangle test. In red light, it was not possible to detect any differences between SFA and CO as well as between UFA and CO. QDA confirmed that there were no differences in any of the attributes for SFA and CO. However, QDA was not carried out for UFA and CO in red light. 4. Discussion Preliminary data examinations showed a tendency (P¼0.09 and 0.1 for ECM yield and DM intake, respectively, data not shown) towards interaction between breed, diet and week in lactation. Similar interactions were found between fat diets and the breeds Holstein and Jersey by Larsen et al. (2012a). Therefore, it was decided to perform analyses within breed. 4.1. Feed intake and milking frequency The visiting and milking frequency to the AMU in a loose housing system is linked to the palatability of the feed offered in the feed bunk and in the AMU, respectively (Madsen et al., 2010). In the present study DR cows showed no difference between treatments in milking frequency or other visiting behaviour to the AMU, whereas DH and DJ cows showed some treatments effects on

M.R. Weisbjerg et al. / Livestock Science 155 (2013) 60–70

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Table 3 Mean daily effects of feeding control ration (CO), ration with saturated ration (SFA) or unsaturated ration (UFA) fat on milk production and composition, and milking unit (AMU) visiting behaviour for Danish Red (DR), Danish Holstein, and Danish Jersey during W1−30 of lactation. Least square mean (LSM) and standard error (SE). CO

DR ECM (kg/d) a Milk (kg/d) Fat (%) Protein (%) Lactose (%) Fat (kg/d) Protein (kg/d) Lactose (kg/d) Daily milking frequency FCE c DH ECM (kg/d) a Milk (kg/d) Fat (%) Protein (%) Lactose (%) Fat (kg/d) Protein (kg/d) Lactose (kg/d) Daily milking frequency FCE c

b

b

SFA

UFA

LSM

SE

LSM

SE

LSM

SE

31.7 32.5 3.87b 3.53 4.92ab 1.23 1.00 1.60 2.38 0.91

1.5 1.5 0.10 0.09 0.04 0.06 0.04 0.08 0.20 0.03

30.3 29.2 4.42a 3.43 4.90a 1.27 1.00 1.43 2.49 0.88

1.2 1.3 0.09 0.07 0.03 0.05 0.04 0.07 0.17 0.02

30.9 30.8 4.00b 3.42 4.98b 1.23 1.05 1.52 2.47 0.86

1.2 1.2 0.08 0.07 0.03 0.05 0.04 0.06 0.16 0.02

34.0 34.1 4.03 3.49b 4.95b 1.34 1.17 1.69 2.89 0.88

1.1 1.2 0.11 0.05 0.03 0.05 0.04 0.06 0.15 0.02

34.5 35.8 4.02 3.30a 4.87a 1.36 1.15 1.75 2.63 0.91

1.3 1.4 0.14 0.05 0.03 0.06 0.04 0.07 0.18 0.02

34.5 36.4 3.79 3.30a 4.91ab 1.34 1.18 1.80 2.48 0.86

1.1 1.2 0.12 0.05 0.03 0.05 0.04 0.06 0.16 0.02

31.6 26.8b 5.18 4.04 4.91 1.34 1.10a 1.31 3.10 0.92

1.5 1.4 0.20 0.10 0.03 0.07 0.05 0.07 0.24 0.02

28.6 22.2a 5.83 4.14 4.88 1.30 0.92b 1.10 3.40 0.88

1.6 1.4 0.22 0.10 0.03 0.07 0.05 0.07 0.25 0.02

28.0 23.1ab 5.59 3.97 4.93 1.21 0.91b 1.13 2.86 0.90

1.4 1.3 0.19 0.09 0.03 0.07 0.05 0.06 0.22 0.02

DJ ECM (kg/d) a Milk (kg/d) Fat (%) Protein (%) Lactose (%) Fat (kg/d) Protein (kg/d) Lactose (kg/d) Daily milking frequency FCE c

b

Different indexes indicate significantly different results within rows (P o0.05). a Energy corrected milk (Sjaunja et al., 1991). b Complete milkings. c Feed conversion efficiency.

visiting behaviour. Weisbjerg and Munksgaard (2009) found that increasing the concentrate allowance in an AMU increased the visiting frequency and MY during W1−10. Furthermore, Madsen et al. (2010) showed an effect of concentrate composition on milking frequency. In the present study, all cows were fed the same type of concentrate and no differences in concentrate intake were encountered during W1−30, hence differences are probably due to the MR. If palatability of the MR in the feed bunk is high relative to the palatability of the concentrate in the AMU, visiting frequencies to the AMU should logically decrease. However, DR and DJ cows showed no differences in MR intakes between treatments and in DH cows the highest intake of MR was found in CO. Feeding UFA was expected to decrease DMI as unsaturated FA in the diet compared to saturated reduce the digestibility of NDF (Pantoja et al., 1994; Weisbjerg and Børsting, 1989), reducing disappearance rate and thereby DMI due to increased rumen fill. A higher palatability might explain why UFA intake did not decrease in the

present study compared to CO. Feeding SFA was also expected to decrease DMI due to higher energy concentration but not as pronounced as UFA (Hermansen, 1989b; Pantoja et al., 1996; Petit et al., 2001). A lower palatability most likely explains why all breeds fed SFA in the present study decreased DMI, as a smell of soap was observed in the SFA MR. 4.2. ECM and milk yield Generally dietary fat supplementation is expected to increase MY, as described by Chilliard (1993) in review of supplementation with saturated fat and protected tallow. However, in the present study MY was reduced in DJ fed SFA or UFA compared to CO during W1−30 and even more pronounced during W1−10. Similarly Smith et al. (1978) found no significant effect on MY of increasing lipid contents of the ration from 2.9% to 14.3% DM (weight basis) in Holsteins, but the MY in W1−7 was highest in the control group as in DJ in the present study.

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DR

ECM, kg/d

40

DH

40

30

30

20

30

20

20 0

10

20

30

0

10

Milk fat, %

Lactation week

0

30

7

5

5

5

3 20

30

10

20

30

0

5

4

4

4

3 20

30

20

30

Lactation week

5

10

10

Lactation week

5

0

30

3 0

Lactation week

3

20

Lactation week

7

10

10

Lactation week

3

Milk protein, %

20

7

0

DJ

40

3 0

10

20

30

0

10

Lactation week

Lactation week

20

30

Lactation week

Fig. 2. Daily energy corrected milk (ECM) yield, fat, and protein concentrations in milk from Danish Red (DR), Danish Holstein (DH), and Danish Jersey (DJ), when fed saturated ration (SFA) (dotted line), unsaturated ration (UFA) (thin line), or control ration (CO) (bold line) during week 1–30 of lactation.

DR

Lactose, %

5.1

DH

5.1

4.8

4.8

4.5

4.8

4.5 0

10

20

4.5 0

30

10

20

30

0

0.25

0.25

0.25

0.2

0.2

0.2

0.15

0.15 0

10

20

10 20 Lactation week

Lactation week

Lactation week

Citrate, %

DJ

5.1

30

30

0.15 0

10

Lactation week

20

Lactation week

30

0

10

20

30

Lactation week

Fig. 3. Daily lactose and citrate concentrations in milk from Danish Red (DR), Danish Holstein (DH), and Danish Jersey (DJ), when fed saturated ration (SFA) (dotted line), unsaturated ration (UFA) (thin line), or control ration (CO) (bold line) during week 1–30 of lactation.

Supplementing Jersey and Danish Red with dietary fat has been shown to render positive responses in fat corrected milk (FCM), whereas Holsteins did not respond in a similar manner (Hermansen, 1989a; Rodriguez et al.,

1997). In contrast, ECM was not affected by dietary treatment in DR and DH in the present study and even appeared to decrease in DH fed SFA during W1−10 (Fig. 2). Son et al. (2000) indicated reduced DMI, when

M.R. Weisbjerg et al. / Livestock Science 155 (2013) 60–70

67

Table 4 Effects of feeding control ration (CO), ration with saturated (SFA) or unsaturated (UFA) fat on milk fatty acid composition (g/kg fatty acids) for Danish Red (DR), Danish Holstein (DH), and Danish Jersey (DJ). Least square mean (LSM) and standard error (SE) of samples from week 8 71; 207 2; and 307 2. CO

SFA

LSM

UFA

P-value

SE

LSM

SE

LSM

SE

DR C4–C14 C16:0 C18:0 C18:1 cis 9 C18:1 transa C18:2 n6 C18:3 n3 CLA cis 9 trans11b

255a 309b 74b 158b 13.8b 17.8 5.4b 4.3b

8 13 5 6 1.5 0.6 0.3 0.4

212b 397a 77b 173b 12.5b 17.4 4.9b 3.6b

3 9 3 6 0.5 0.6 0.2 0.1

229b 242c 125a 230a 25.1a 17.9 7.2a 6.8a

6 7 5 9 1.4 0.6 0.3 0.5

o 0.001 o 0.001 o 0.001 o 0.001 o 0.001 NS o 0.001 o 0.001

DH C4–C14 C16:0 C18:0 C18:1 cis 9 C18:1 transa C18:2 n6 C18:3 n3 CLA cis 9 trans11

252a 332b 82b 153c 12.3b 16.5b 4.3b 3.4b

5 13 2 6 0.5 0.5 0.2 0.4

224b 397a 77b 172b 13.4b 17.7b 4.9b 4.2b

4 9 2 4 0.5 0.6 0.2 0.2

235ab 235c 129a 256a 29.8a 19.8a 7.9a 8.8a

9 7 5 7 1.3 0.6 0.4 0.8

0.007 o 0.001 o 0.001 o 0.001 o 0.001 o 0.001 o 0.001 o 0.001

DJ C4–C14 C16:0 C18:0 C18:1 cis 9 C18:1 transa C18:2 n6 C18:3 n3 CLA cis 9 trans11

247a 356b 97b 147b 13.5b 16.4a 4.5b 3.2b

6 9 6 9 0.9 0.5 0.2 0.2

260a 393a 83c 131b 11.7b 15.4ab 4.1b 2.9b

4 5 3 4 1.0 0.5 0.2 0.2

232b 272c 152a 201a 22.7a 14.8b 5.9a 4.7a

4 5 3 4 1.0 0.4 0.2 0.3

0.001 o 0.001 o 0.001 o 0.001 o 0.001 0.047 o 0.001 o 0.001

Different indexes indicate significantly different results within rows (P o0.05). a Sum of C18:1 trans 9, 10, 11 FA. b CLA cis 9 trans 11 and minor amounts of other CLA isomers. Table 5 Sensory analysis of milk from Danish Holstein cows. Samples

Triangle testa

P-value

UFA-CO—normal light UFA-CO—normal light SFA-CO—red light UFA-CO—red light

17/27 21/30 13/27 12/27

0.002 o 0.001 NS NS

a The number indicates number of correct answers compared to total answers.

supplementing 3% DM Ca-salts of long chain FA (LCFA) (weight basis), as the reason for a numerically lower MY in Holstein cows in W1−5 compared to control feed cows. In general, NEI does not explain the lack of ECM response in DR and DH or the decrease in ECM in DJ. The lack of response in ECM to dietary fat in the present study could be due to a negative effect of feeding fat immediately after calving. Both Kokkonen et al. (2004) and Ruegsegger and Schultz (1985) found that supplementing dietary fat decreased MY in W1−4 compared with control, but after W5 the cows supplemented dietary fat surpassed control cows and had a higher MY. In the present study, DR fed UFA and DH fed SFA surpassed milk production of CO in about week W20 and W15, respectively. This indicated that there might be a negative effect of feeding fat right

after calving and that the negative effect lasted during W1–30 for DJ fed SFA or UFA and DR fed SFA. However, Salfer et al. (1995) found the greatest increase in FCM yield, when increasing ration fat concentration from 3.17% to 4.99% ether extract of DM by adding partially hydrogenated tallow at parturition compared to both W−2 and W7. Salfer et al. (1995) found that cows supplemented with fat from 35 days postpartum were more persistent in milk and FCM yield than control. In the present study, DR and DJ fed UFA were more persistent compared with CO (Fig. 3), while DH fed SFA tended to be more persistent than CO. The effect found by Salfer et al. (1995) might be an effect of adding extra energy at a lactation stage where MY normally starts to decrease. 4.3. Milk fat The milk fat concentration in the present study was within the expected range from 3.5 to 5.5% and followed the expected curve with a relatively high concentration after parturition and a lower concentration in later lactation (Barber et al., 1997) but the response to dietary fat was different between breeds. Hermansen (1989b) for DH cows found that by increasing the amount of saturated fat from 28 to 55 g FA/kg DM the milk fat concentration increased to 4.49% and 4.71% compared with 4.10%, when cows were supplemented the same amount of FA from tallow.

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Also Jerred et al. (1990) supplemented 0–5% of DM of rumen inert fat to Holstein cows and found an increased milk fat concentration. As expected, feeding SFA or UFA had a positive effect (sign. for SFA) on fat concentration compared with CO for both DR and DJ in the present study, whereas there was no effect of dietary treatment on fat concentration for DH even though UFA tended to reduce milk fat concentration compared with SFA or CO. 4.4. Milk protein The general observation is that dietary fat decreases milk protein concentration during lactation (Doreau and Chilliard, 1997; Palmquist and Jenkins, 1980). Total protein production is however usually not affected by dietary fat, hence the decreased protein concentration seems to be due to a dilution effect (Doreau and Chilliard, 1997; Palmquist and Jenkins, 1980; Rodriguez et al., 1997). In the present study, milk protein production was depressed for Jersey when feeding SFA or UFA, whereas the protein concentration was only significantly reduced for DH. Contrarily, protein concentration for DJ increased (ns), possibly due to the reduced MY. 4.5. Milk citrate content Jerseys generally have a higher de novo FA synthesis compared to Holsteins (Beaulieu and Palmquist, 1995; Carroll et al., 2006; Morales et al., 2000; White et al., 2001). In the present study, DJ fed SFA or UFA had a numerically lower citrate concentration and fat production compared to CO. This could indicate that the DJ maintained the de novo FA synthesis at a high level even though they were fed SFA or UFA. The synthesis was however not high enough to increase fat production compared to CO. The increased fat production for DJ fed CO might be explained by an increased mobilisation. DR fed SFA had a lower citrate concentration compared with UFA. This could indicate that the DR fed SFA maintained the de novo FA synthesis at a high level even though they were fed SFA. Contrary DR fed UFA reduced de novo FA synthesis, indicated by increased citrate concentration. Fat production was not significantly affected by dietary treatment, but DR fed SFA had a numerically higher fat production, which might be explained by the higher de novo fat synthesis. Petit et al. (2001) found the opposite for Holsteins as saturated fat reduced de novo FA synthesis more than unsaturated fat. 4.6. Milk fatty acid composition The de novo FA synthesis includes C4–C14 as well as part of C16 and the milk fat content of these FA decreased for DR and DJ fed UFA compared to CO, whereas the decrease was only significant for C16 for DH. For DJ this was not accompanied by a higher milk citrate concentration, however, milk fat concentration increased for DJ fed UFA compared to CO, thus concentration of de novo synthesised FA in whole milk was not affected. Feeding SFA increased milk fat content of C16 for all breeds and this increase was highest for DR and lowest for DJ. Changes in de novo FA synthesis could only be assessed by changes in C4–C14 as large amounts of C16 were

supplied from feed for the SFA treatment. A decrease in the milk fat content of C4–C14 was observed for DR and DH fed SFA compared to CO whereas the milk fat content of C4–C14 was not affected for DJ. For DH and DJ this was in accordance with the changes in milk citrate content, but for DR the decreased milk citrate content could not be related to increased content of C4–C14 in milk fat. However, milk fat concentration increased which reduced the decrease in C4– C14 concentration in whole milk compared to the decrease of those FA in milk fat. The milk fat content of C18:0 decreased for DJ fed SFA which could be related to the reduced milk yield. The response of DR and DH to SFA feeding was similar to results obtained from feeding Holstein cows a lipid supplement rich in C16 presented by Warntjes et al. (2008). For UFA feeding compared to CO the increases in milk fat content of C18:0 and C18:1 cis9 were similar between breeds whereas the relative changes in C18:1 trans11 and polyunsaturated FA were similar for DR and DJ, but for DH the relative increases were clearly higher. Thus, if UFA feeding is to be used for controlling milk FA composition towards a higher content of polyunsaturated FA, it is more beneficial to use DH than DR or DJ. However, the increase in polyunsaturated FA was accompanied by an increase in C18:1 trans FA and this may be undesirable with regards to human health. The differences between breeds when UFA was fed suggest that the biohydrogenation was lower for DH compared to DR and DJ. This decreased biohydrogenation in the rumen of DH could be due to a ruminal microflora being more sensitive to the toxicity of polyunsaturated FA (Jenkins, 1993). A lower biohydrogenation in the rumen of DH compared to DJ has also been reported by Larsen et al. (2012a). Differences between breeds in FA composition of milk fat are affected by other factors as well, and especially the mammary desaturase activity is important as the main parts of C18:1 cis 9 as well as CLA cis 9 trans11 in milk fat are synthesised by mammary desaturation of C18:0 and C18:1 trans 11, respectively. This desaturase activity is lower of DJ than of DH (Larsen et al., 2012a) and in the present study this difference explains why concentrations of C18:0 were higher and C18:1 cis 9 were lower in DJ compared to DH. These values were similar for DH and DR suggesting that the desaturase activity of DR is similar to that of DH. 4.7. Milk sensory analysis The sensory analyses demonstrated that all kinds of feed used in the present study could be used without sensory consequences as no sensory differences were detected between SFA and CO and only small but not consistent sensory differences were detected between UFA and CO. However, Hedegaard et al. (2006) have analysed sensory properties of milk where FA composition has been modified by feeding UFA or SFA, although at higher levels compared to our present study. They report off-flavours of milk from SFA feeding due to lipolysis and of milk from UFA feeding due to oxidation. 5. Conclusion In conclusion the effects of increasing ration energy density by substituting barley with either saturated or

M.R. Weisbjerg et al. / Livestock Science 155 (2013) 60–70

unsaturated fat during W1−30 varied among breeds. Generally DMI was reduced while NEI was unaffected by feeding SFA or UFA. Fat supplementation did not affect MY in neither DR nor DH. The DJ fed SFA or UFA responded unexpectedly with a lower MY than CO, which might be due to a higher mobilisation for cows fed CO. Milk FA composition was highly influenced by feeding both SFA and UFA.

Conflict of interest statement There are, to my best knowledge, no conflicts of interest.

Acknowledgements The authors wish to express sincere thanks to Carsten Brogaard Jensen, NLM Vantinge ApS, for generously providing the Lipitec Bovi 80 and the Danish Cattle Research Centre for carrying out the practical work associated with the presented research. Anders B. Strathe is acknowledged for helping setting up the random regression model. The work was funded by the Danish Cattle Federation, Danish Ministry of Food, Agriculture and Fishery, Mælkeafgiftsfonden and Aarhus University. References

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