Milk production, milk composition, blood composition, and conception rate of transition dairy cows fed different profiles of fatty acids

Abstract

Petit, H. V. and Benchaar, C. 2007. Milk production, milk composition, blood composition, and conception rate of transition dairy cows fed different profiles of fatty acids. Can. J. Anim. Sci. 87: 591-600. A total of 153 lactating Holstein cows averaging 695 kg body weight (standard error = 11) were allotted 6 wk before the expected date of parturition to 51 groups of three cows blocked for similar calving dates to determine the effects of feeding different profiles of fatty acids from 6 wk before calving on feed intake, milk production and composition, conception rate, and embryo mortality in the subsequent lactation. Cows within each block were assigned to one of the three isoenergetic total mixed diets based on either whole flaxseed (FLA), Megalac ® (MEG) or micronized soybeans (SOY). Diets were fed for ad libitum intake from 6 wk before calving to day 50 of pregnancy for pregnant cows, or 120 d postpartum for those not diagnosed pregnant after artificial insemination (AI). Diet had no effect on prepartum dry matter intake but postpartum intake was 9% higher for cows fed FLA than for those fed MEG or SOY. Milk production and fat concentration were similar among treatments. Conception rate at first AI was higher for cows fed FLA (54.3%) than for those fed SOY (26.9%). Conception rate at first AI was similar for cows fed FLA and MEG and it was similar for those fed MEG and SOY. Cows fed MEG tended to have higher embryo mortality than those fed FLA (41.7 vs. 10.5%, P = 0.06) and SOY (41.7 vs. 0%, P = 0.08) at first AI and there was no difference among treatments at second AI. Total embryo mortality was similar for cows fed FLA and SOY but cows fed MEG had higher total embryo mortality than those fed SOY (35.3 vs. 9.1%) and there was a trend (P = 0.07) when MEG was compared with FLA (35.3 vs. 9.5%). These data suggest that feeding flaxseed during the prepartum period has little effect on production in the subsequent lactation but could improve fertility of dairy cows.Key words: Dairy, flaxseed, milk production, reproduction, fatty acids Petit, H. V. et Benchaar, C. 2007. Production de lait, composition du lait, composition du sang et taux de conception chez la vache laitière recevant différentes sources de gras. Can. J. Anim. Sci. 87: 591-600. Un total de 153 vaches laitières Holstein pesant en moyenne 695 kg (erreur standard = 11) ont été distribuées au hasard 6 semaines avant la date prévue de vêlage en 51 groupes de trois vaches à partir de la semaine 6 avant le vêlage afin de déterminer les effets de différents profils d'acides gras alimentaires sur l'ingestion, la production et la composition du lait, le taux de conception, et la mortalité embryonnaire lors de la lactation suivante. Les vaches à l'intérieur de chaque groupe one reçu une des trois rations totales mélangées isoénergétiques basées sur du lin (FLA), du Megalac ® (MEG) ou du soya micronisé (SOY). Les rations ont été offertes à volonté à partir de 6 semaines avant le vêlage jusqu'au jour 50 de gestation pour vaches devenues gestantes ou jusqu'au j...

Colostrum and milk fatty acids of dairy cows as influenced by extruded linseed supplementation during the transition period

“…Colostrum and Milk as well as Efficiency of 18:3 Transfer from Feed to Milk In general, the present results agree with the literature (Mustafa et al 2003;Petit and Benchaar 2007), with linseed supplementation increasing concentrations of various 18 FA, while the control supplement favoured 16:0. In addition, the associated changes in the other FA and respective groups of FA were as expected.…”

“…In addition, the associated changes in the other FA and respective groups of FA were as expected. The fat supplements used in the present experiment allowed the creation of a significant difference in the intake levels of 16 and 18 FA, at levels similar to those reported by Petit and Benchaar (2007). Cows consumed close to 400 g d (1 of 16:0 when they received the C supplement, of which about 60 g were excreted in milk daily, while for cows receiving the L supplement, consuming about 275 g d (1 of 18:3, approximately 3 g d (1 were excreted in milk.…”

“…This value is slightly higher than observed by Petit and Benchaar (2007). Petit (2002) as well as Petit and Benchaar (2007) reported higher post-calving DMI for cows that received a linseed diet from 6 wk pre-partum to 50 d post-calving compared with cows receiving a saturated fat. No such difference was observed in the present study.…”

“…Production levels of their cows were similar to those used in the present study, although contents of milk constituents were much lower (averages were respectively 3.8 and 2.9% for fat and protein in their study, compared with 5.1 and 3.4% in the present study). In contrast to Petit and Benchaar (2007) and to CC, control pre-and postcalving;…”

“…These results support data from the present experiment, although the lack of difference in plasma metabolites between the four treatment groups was facilitated by the fact that cows were all receiving the same amount of fat and consumed similar levels of energy. Petit and Benchaar (2007) used transition cows to compare fat supplements based on whole linseed, a commercial product containing mainly palmitic and oleic acids, and micronized soybeans, and found no treatment effect on either milk composition or production. Production levels of their cows were similar to those used in the present study, although contents of milk constituents were much lower (averages were respectively 3.8 and 2.9% for fat and protein in their study, compared with 5.1 and 3.4% in the present study).…”