Proceedings, Western Section, American Society of Animal Science
Vol. 53, 2002
EFFECTS OF FEEDING HIGH LINOLEATE SAFFLOWER SEEDS PREPARTUM ON LEPTIN 1CONCENTRATION, WEANING, AND RE-BREEDING PERFORMANCE OF BEEF HEIFERS
2223 T. W. Geary, E. E. Grings, M. D. MacNeil, and D. H. Keisler2USDA-ARS, Fort Keogh Livestock and Range Research Laboratory, Miles City, MT 59301 and 3 University of Missouri, Columbia, MO 65211
effect on these traits in another study (Alexander et al., 2001). ABSTRACT:; Our objective was to identify potential
The objective of this study was to identify potential mechanisms by which prepartum diets high in linoleic acid
mechanisms by which prepartum diets high in linoleic acid increase calf weaning weight and heifer re-breeding
might increase calf weaning weight and heifer re-breeding performance. Thirty-six Angus and Hereford-Angus heifers
performance. that conceived on the same day to one sire were stratified by
weight (436.1 ? 27.8 kg) and body condition score (BCS, 4.4
Materials and Methods ? 0.7) and within strata assigned to receive a prepartum diet
high in linoleic acid (S) or control (C) diet. Diets were
Thirty-six Angus and Hereford-Angus heifers that isocaloric and isonitrogenous. Heifers were fed in pens of six
conceived on the same day to one sire were stratified by weight from d -56 until calving. At calving, heifers were housed
(436.1 ? 27.8 kg) and body condition score (BCS, 4.4 ? 0.7; together and fed the same diet for the duration of the study.
1 = emaciated, 9 = obese) and within strata assigned to receive Blood samples were collected on d -56, -42, -28, -14, -10 to d
3, and twice weekly from d 0 (calving) to d 172 postpartum. a prepartum diet high in linoleic acid (S) or control (C) diet
Hip height, BW, BCS, and ultrasound fat depth were measured (Table 1). Diets were isocaloric and isonitrogenous and fed as every 28 d. Heifers were exposed to one bull from d 126 to 175 a total mixed ration. Heifers were fed in pens of six (three and examined for pregnancy by ultrasound on d 172 and 209. replicates per treatment) from d -56 until calving (d 0). At Ultrasound and twice weekly progesterone measurements calving, heifers were housed together and fed the control diet were used to estimate date of conception. Neither weight nor until approximately d 120 postpartum. From d 120
postpartum until weaning, heifers were together on pasture. BCS at calving differed (P > 0.10) between heifers fed S (455
Hip height, BW, BCS, and ultrasound fat depth were measured kg, 5.8) vs C (445 kg, 5.8). Calf birth weight and dystocia
every 28 d until the end of breeding. Dystocia score and calf score did not differ (P > 0.10) between heifers fed S or C, but
vigor score were recorded at the time of parturition (Bellows et calf vigor was greater (P < 0.05) in calves born to heifers
al., 2001). Within 12 h postpartum, calf sex, calf birth BW, receiving S. Weight, BCS, fat depth over the back and rump,
dam BW, and BCS were recorded. Calf weights were recorded hip height:weight, and serum leptin concentrations were not
at approximately 90 and 209 d postpartum and were adjusted affected (P > 0.10) by treatment or treatment by day interaction.
for sex and age. Pregnancy rate, postpartum interval, and interval from calving
to conception did not differ (P > 0.10) between heifers fed S
Table 1. Composition of prepartum diets (81%, 129 d, and 137 d) vs C (88%, 130 d, and 140 d). Calf aItem Control Safflower weaning weights adjusted for age and sex were similar
Ingredient between heifers fed S (241 ? 18 kg) vs C (232 ? 32 kg). We
Corn silage 51.5 53.5 were unable to identify differences between heifers fed S vs C
Alfalfa hay 34.9 38.3 and thus, unable to investigate potential mechanisms of action
Barley 12.4 - related to previously reported improvements in re-breeding
Soybean meal 1.2 - and weaning performance.
Safflower - 8.7
Key Words: Linoleic Acid, Leptin, Heifers
Protein 11.7 11.7 Introduction
Ether extract 2.2 5.3
ADF 27.7 27.9 First-calf heifers experience longer postpartum intervals
ME, Mcal/kg 2.2 2.2 following calving and lower pregnancy rates to defined abreeding seasons than older cows (Bellows et al., 1982). Both Ingredients and analyses are on a dry matter basis. prepartum and postpartum nutrition have major effects on Blood samples were collected on d -56, -42, -28, -14, subsequent reproduction (Randel, 1990). Recent studies have daily from d -10 to d 3, and twice weekly from d 0 to d 172 suggested that dietary fat may play an important role in postpartum. Serum was harvested from blood samples and oreproduction and cow productivity. Prepartum diets high in stored at –20C until analyzed for concentration of linoleic acid improved subsequent pregnancy rates and progesterone (Bellows et al., 1991) and leptin (Delavaud et al., weaning weights in one study (Bellows et al., 2001), but had no 2000). Intra- and inter-assay coefficients of variation for both
assays were less than 10%. Heifers were considered to have 6.5Cresumed estrous cycles when concentrations of serum Sprogesterone were greater than 1 ng/mL in two consecutive 6.0
5.5Heifers were exposed to one bull from d 126 to 175 and
examined for pregnancy by ultrasound on d 172 and 209.
5.0Ultrasound and twice weekly progesterone measurements
were used to estimate date of conception.
4.5Effects of prepartum diet and pen within prepartum diet Body Condition Scoreon gestation length, sex adjusted calf birth BW, dystocia score, 4.0calf vigor score, adjusted 90 d BW, 205 d BW, dam BW and -56-280285684112140168BCS at parturition, postpartum anestrous interval, and interval
from calving to conception were analyzed using PROC GLM Day
of SAS (SAS Inst., Cary, NC). Pen within diet was used as the error term. Differences in pregnancy rate between treatments Figure 1. Average body condition scores of heifers fed control was determined using Chi square. Differences in BCS, fat (C) vs safflower (S) diets for 56 d prepartum (d 0 = depth over the back and rump, hip height:weight, dam BW, calving).
and leptin as affected by prepartum diet, day or diet by day
interaction were analyzed using PROC MIXED of SAS (SAS Discussion
Inst., Cary, NC). Repeated observations were made across
days and a first order autoregressive covariance structure was Heifers fed safflower diets in the present study did not assumed. One heifer that received the C diet experienced experience improved rebreeding performance as was reported nerve damage to her rear legs during calving and was by Bellows et al. (2001) who fed prepartum diets high in destroyed. One heifer that received the S diet gave birth to a linoleate or as was reported by Espinoza et al. (1995) who fed dead calf and another heifer that received the S diet would not prepartum diets high in calcium soaps of fatty acids. The long claim her calf. Data from these three heifers were not included postpartum anestrous intervals observed among heifers in the in the analyses. present study provided the opportunity for any potential benefit
of fat supplementation during late gestation to have been
Results detected had it existed. Bellows et al. (2001) did not detect a
difference in the percentage of heifers cycling at the onset of
There were no differences (P > 0.10) in BW or BCS at breeding. Frequent BCS and ultrasound measurements of calving between heifers fed S (455 kg and 5.8, respectively) vs body fat indicated that heifers in both treatments deposited fat C (445 kg and 5.8, respectively). Body condition scores of similarly. Serum concentrations of leptin were numerically heifers in both treatment groups increased about 1.5 condition greater following calving in heifers fed C diets. scores during the first 28 d of the study, and remained relatively 4.5CPostpartum anestroushigh throughout the study (Figure 1). Calf birth weight and Sintervaldystocia score did not differ (P > 0.10) between heifers fed S Calving4.0vs C, but calf vigor was greater (P < 0.05) in calves born to
heifers receiving S. Gestation length was longer (P < 0.05) for 3.5heifers receiving S (284 ? 0.8 d; Mean ? SEM) than heifers
receiving C (281 ? 1.0 d; Mean ? SEM). Weight, BCS, fat 3.0depth over the back and rump, and hip height:weight ratio were
not affected (P > 0.10) by treatment or treatment by day 2.5interaction. Serum concentrations of leptin did not differ (P > Leptin Concentration (ng/mL)0.10) between heifers fed S vs C diets. Serum concentrations 2.0of leptin were also not affected (P > 0.10) by treatment by day -56-28-10-8-6-4-20214427098126154interaction (Figure 2). Pregnancy rate, postpartum anestrous Dayinterval, and interval from calving to conception did not differ
(P > 0.10) between heifers fed S (81%, 129 d, and 137 d) vs
Figure 2. Serum concentration of leptin for heifers receiving C (88%, 130 d, and 140 d). Calf weaning weights adjusted for
the high fat (S) vs control (C) diet for 56 d prepartum age and sex were similar (P > 0.10) between heifers fed S (241
(day 0 = calving). ? 18 kg) vs C (232 ? 32 kg).
Others have reported increased calf gain from cows fed
prepartum diets high in fat (Espinoza et al., 1995; Bellows et
al., 2001). While weaning weights did not differ, the difference
in weaning weights of calves from heifers fed S vs C diets were
of the same magnitude as those reported by Bellows et al.
(2001). There were insufficient animals in the present study to
detect such differences given the variation that typically exists Bellows, R. A., E. E. Grings, D. D. Simms, T. W. Geary, and among animals. The diets fed in the current study were similar J. W. Bergman. 2001. Effects of feeding supplemental in nutrient composition to diets fed previously. Safflower fat during gestation to first-calf beef heifers. Prof. Anim.
Sci. 17:81-89. seeds (Carthamus tinctorius L., variety Morlin) fed in this
study were a genotype selected for high linoleate content
Bellows, R. A., R. E. Short, and G. V. Richardson. 1982. (Bergman, 1992).
Effects of sire, age of dam and gestation feed level on The longer gestation length among heifers receiving S
dystocia and postpartum reproduction. J. Anim. Sci. diets in the present study may account for the improved calf
55:18-27. vigor at birth. Others have reported no improvement in calf
vigor with high fat prepartum diets (Alexander et al., 2001;
Bellows, R. A., R. B. Staigmiller, J. M. Wilson, D. A. Phelps, Bellows et al., 2001). Improved vigor may provide calves the
and A. Darling. 1991. Use of bovine FSH for opportunity to gain weight faster when environmental
Superovulation and embryo production in beef heifers. conditions are favorable and could be related to the improved
Theriogenology 35:1069-1082. cold tolerance of calves from heifers fed high fat diets
(Lammoglia et al., 1999). Others have not reported differences
Bergman, J. W. 1992. Montana 2000 and Morlin: Safflowers in gestation lengths among heifers fed high fat diets. Calf sex
for expanding markets. Mont. Ag. Res. 9:34. can affect gestation length, but sex ratio did not differ in the
present study. Bellows et al. (2001) reported a tendency for
Delavaud C., F. Bocquier, Y. Chilliard, D. H. Keisler, A. increased calf birth weight among heifers fed a high fat diet.
Gertler, and G. Kann. 2000. Plasma leptin determination Heifers in the current study gave birth to calves from a single
in ruminants: effect of nutritional status and body fatness sire, and while gestation lengths were longer among heifers
on plasma leptin concentration assessed by a specific receiving the S diet, calf birth weights were not different
RIA in sheep. J. Endocrinol. 165:519-526. between treatments.
Implication Espinoza, J. L., J. A. Ramirez-Godinez, J. A. Jimenez, and A.
Flores. 1995. Effects of calcium soaps of fatty acids on
This study was designed to identify the mechanism(s) by postpartum reproductive activity in beef cows and which supplemental fat in the prepartum diet might improve growth of calves. J. Anim. Sci. 73:2888-2892. calf and rebreeding performance. Other than improved calf
vigor, no differences were detected that would suggest any Lammoglia, M. A., R. A. Bellows, E. E. Grings, J. W. beneficial effect of providing first calf heifers a prepartum diet Bergman, R. E. Short, and M. D. MacNeil. 1999. high in fat. However, given the typical variability among Effects of feeding beef females supplemental fat during animals for many of the phenotypes observed, concluding that gestation on cold tolerance in newborn calves. J. Anim. these diets had similar effects may be premature. Sci. 77:824-834.
Literature Cited Randel, R. D. 1990. Nutrition and postpartum rebreeding in
cattle. J. Anim. Sci. 68:853-862.
Alexander, B. M., D. L. Hixon, B. W. Hess, B. L. Garrett, J. D.
Bottger, and G. E. Moss. 2001. Influence of
fat-supplementation on beef cow reproduction and calf
performance. J. Anim. Sci. 79(Suppl 2):118(Abstr).