Condition Score Change Research Articles

The effects of processed, urea-treated whole-crop wheat or maize silage and supplementation of whole-crop wheat on the performance of dairy cows

Forty-four early lactation dairy cows were divided into four treatment groups to examine the effects of processed, urea-treated whole-crop wheat (pWCW), maize silage and carbohydrate supplement type to pWCW on dry matter (DM) intake and milk production. All cows received 8.5 kg/day of concentrate with cows fed the pWCW receiving an additional 2 kg/day of rolled wheat (W-pWCW) or 0.7 kg/day lactose and 1.3 kg/day rolled wheat (L-pWCW) or 2.3 kg/day of molasses (M-pWCW), whilst the maize silage (Maize) treatment received an additional 2 kg/day of rolled wheat. The pWCW or maize forages were mixed 2:1 on a DM basis with first cut grass silage and cows remained on the experimental treatments for 15 weeks. The pWCW and maize silage had a DM content of 823 and 310 g/kg, crude protein of 143 and 76 g/kg DM, and starch content of 350 and 308 g/kg DM respectively. Milk yield was similar across treatments averaging 34.3 kg/day. By contrast, milk protein concentration (g/kg) was higher ( P<0.01) in cows fed M-pWCW compared with L-pWCW. There was no significant effect of treatment on milk fat content (g/kg) or fat and protein yield (kg/day). Cows fed the maize silage ate less forage than those receiving W-pWCW whilst within the pWCW treatments, those fed lactose ate less than those receiving molasses (mean values of 10.7, 13.3, 12.2 and 14.6 kg DM/day for Maize, W-pWCW, L-pWCW and M-pWCW respectively; P<0.001). There was no significant difference between treatments in average body condition score, live weight (kg) or live weight change (kg/day). There was also no significant effect of supplement to pWCW on plasma β-hydroxybutyrate concentration, whilst cows fed pWCW supplemented with molasses had the lowest plasma urea levels over the experimental period ( P<0.05). In conclusion, cows fed processed, urea-treated WCW had a similar milk production to those fed good quality maize silage but consumed more forage, whilst supplementation of pWCW with lactose tended to increase milk yield and molasses increased milk protein concentration, with little effect on component yield.

Effects of willow ( Salix) supplementation for 31 and 63 d on the reproductive performance of ewes grazing low quality drought pasture during mating

A grazing experiment, conducted for 63 d from 12 January 2003, in the late summer/autumn of 2003, at Massey University's Riverside Farm, near Masterton (New Zealand), evaluated the length of feeding necessary (0, 31 and 63 d) to achieve reproduction responses from supplementation with willow tree trimmings in ewes grazing dry summer pastures of low nutritive value during mating. A rotational grazing system with 300 mixed age Romney ewes (54.3 ± 0.56 kg) was used, with 100 ewes per treatment (control, short supplementation and long supplementation). All ewes were offered 0.70 kg dry matter (DM)/d of low quality pasture, containing 78% dead matter, with pre- and post-grazing pasture masses of 1261 and 821 kg DM/ha, respectively. The effect of short (31 d) and long (63 d) willow supplementation (1.4 kg fresh/ewe/d) on live weight (LW) and body condition score (BCS) change, reproductive rate at pregnancy scanning, lambing, docking and weaning, and wool production was measured. Pasture consumed was typical of drought pasture, very high in neutral detergent fibre (NDF; 603 g/kg), low in organic matter digestibility (49%; OMD), and contained substantial concentrations of the anti-nutritional fungal metabolites zearalenone ( Z) and trichothecenes. The willow diet selected was a superior feed to the drought pasture diet selected, with a higher N content, OMD and ME and it contained substantial concentrations of the secondary compounds condensed tannin (CT), salicin and other phenolic glycosides. Willow supplementation for 63 d (long treatment) reduced ewe LW loss (−96 g/d versus −147 g/d; P < 0.05) and loss in BCS (−0.79 versus −1.09; P < 0.05), compared to unsupplemented ewes, but these differences disappeared in the post-treatment period. There were no treatment effects on reproductive rate at scanning and lambing, probably due to the toxic concentrations of Z in the pasture consumed by ewes during mating (1.5 mg/kg DM). However, the long treatment weaned 13% more lambs than control ewes, due to a 9% unit reduction in post-natal lamb mortality from 17.1 to 8.4% ( P < 0.05). There were no treatment effects on wool production and staple length, only a small treatment effect on the LW of male lambs at birth and no effect on lamb weaning weight. Overall results from 3 years of experimentation showed that supplementing ewes grazing drought pasture during mating with poplar and willow tree fodder consistently reduced LW loss and loss in BCS and substantially increased ultrasound scanning and lambing percentages, provided that the pasture or tree material was not contaminated with fungi that produce oestrogenic mycotoxins. When adjusted to equal birth rank, supplementation with tree fodder during mating also reduced post-natal lamb mortality in all 3 years, with overall means of 17.8 and 11.7% for the control and tree supplemented groups, respectively.

Profiles of genetic changes of linear type in Holstein Friesians

Changes in body condition score and other linear type traits can be indicative of changes in body energy balance in dairy cattle (Coffey et al., 2003). As an animal proceeds through her lactation it is expected that body shape and fatness levels will change both with peaks and troughs of lactation as well as changes as the animal grows and matures. Wall et al. (2005) showed that udder support (US) was correlated to fertility; cows with weaker udders had poorer fertility. If there are differences between animals in terms of how their udders grow and mature across the first lactation, this could be indicative of health and fertility problems later in life. The aim of this study was to examine how type traits recorded in the national dairy population change over the first lactation and if there is a difference between sires in the type profiles of their daughters.

Effects of Different Levels of Dry-Rolled Corn or Barley on the Utilization of Medium Quality Meadow Hay with Steers and Performance with Heifers

In Trial 1, five Angus-Gelbvieh crossbred steers (BW = 295 ± 3kg) fitted with rumen cannulas were used in a 5 × 5 Latin square design to determine intake and digestibility of medium-quality native grass hay (9.5% CP) when supplemented with 0.25% BW dry-rolled corn (low corn; LC), 0.50% BW dry-rolled corn (high corn; HC), 0.25% BW dry-rolled barley (low barley; LB), 0.50% dry-rolled barley (high barley; HB), or when receiving no supplement (NS). Forage DMI decreased with increasing level of corn (P<0.001) and with increasing level of barley (P=0.018) in the supplement (2.27, 2.06, 1.76, 2.11, and 1.95 ± 0.08% BW for NS, LC, HC< LB, and HB, respectively). Organic matter, NDF, and ADF digestibility were not altered (P<0.53) by supplemental treatment. Ruminal fluid pH was significantly changed by supplementation, but pH remained well above 6.2. In Trial 2, 40 weaned, Angus × Gelbvieh heifers (BW = 302 ± 8kg) were used to evaluate measure weight gain of animals fed diets similar to Trial 1. Supplemental treatments were NS, 0.68kg of rolled corn (LC), 1.36kg of rolled corn (HC), 0.68kg of rolled barley (LB); and 1.36kg of rolled barley (HB). Weight gain during the 77-d period was greater (P= 0.002) for all heifers receiving supplements (35, 48, 47, 45, and 55 ± 3kg for NS, LC, HC, LB, and HB, respectively). Both corn and barley supplementation had a linear effect (P<0.04) on weight gains. Neither condition score (5.1, 5.2, 5.2, 5.4, and 5.4 for NS, LC, HC, LB, and HB, respectively) nor condition score change was affected (P<0.37) by treatment. Supplementation with either corn or barley had a quadratic effect on forage and total DMI. These data suggest that with a medium quality meadow hay, either corn or barley can be fed up to 0.5% of BW without affecting total DMI or dietary DM and fiber digestibility, although supplements did decrease forage DMI.

Supplementation of dairy cows with propylene glycol during the periparturient period: effects on body condition score, milk yield, first estrus post-partum, beta-hydroxybutyrate, non-esterified fatty acids and glucose concentrations

The objective of this study was to analyse the effects of propylene glycol (PPG) supplementation to periparturient cows on: milk yield, changes in body condition score (BCS), days to first oestrus after calving, and on the beta-hydroxybutyrate (BHBA), non-esterefied fatty acids (NEFA) and glucose concentrations. Twenty-three Holstein cows were distributed into two treatments: a) 300 mL of PPG (group treatment, 11 cows), b) 300 mL of water (group control, 12 cows), administered via drench in periparturient period. BCS was evaluated on days -10, 0, 15, 30, 45 and 60 relative to calving date. There was no effect of treatment or time on milk yield, although the interaction of time*treatment was significant and during the 4th and 5th week of lactation, milk yield was significant higher in treatment group. Days to first oestrus of PPG and control group were on average 40.2 and 45.2 respectively (P&gt;0.05). There was no effect of treatment on body condition score (BCS) from calving to sixty days post partum. There was no effect of treatment or interaction of time*treatment on plasma parameters (BHBA, NEFA and glucose) but there was an effect of time on glucose and NEFA. However, based on an analysis of covariance, using BCS as the covariate, an effect of treatment on plasma concentrations of BHBA was observed. In conclusion, supplementation of propyleneglycol has a minor effect to alleviate the negative metabolic effects that normally occur at early lactation in dairy cows.

The effect of different levels of poplar ( Populus) supplementation on the reproductive performance of ewes grazing low quality drought pasture during mating

A grazing experiment, conducted for 71 days from 31 January to 12 April in the late summer/autumn of 2001 at Massey University’s Riverside Farm, in Masterton (New Zealand), compared the effect of poplar supplementation ( Populus deltoides × nigra, clone Veronese), during mating, on ewe production and reproduction when grazing low quality drought pasture. A rotational grazing system with 300 mixed age Romney ewes ( 57.1±0.68 kg ) was used, with 100 ewes per treatment. All ewes were offered 0.70 kg dry matter (DM)/day of low quality pasture, containing 84% dead matter, with pre- and post-grazing pasture masses of 1040 and 531 kg DM/ha. Ewes were randomly allocated to three treatment groups, being: high supplementation, low supplementation and control. The high and low treatment groups were offered 1.50 kg/ewe/day (fresh) and 0.75 kg/ewe/day (fresh) poplar cuttings, respectively. The effect of poplar supplementation on liveweight (LW) and body condition score (BCS) change; reproductive rate at pregnancy scanning, lambing, docking and weaning; and wool production and staple length was measured. The poplar diet selected contained 22 g/kg DM of phenolic glycosides and higher levels of nitrogen (N; 28.4 g/kg DM versus 17.8 g/kg DM) and condensed tannin (CT; 7.0 g/kg DM versus 1.5 g/kg DM) and was of higher organic matter digestibility (0.66 versus 0.52) than the pasture diet selected. Voluntary DM intake of poplar progressively increased with time of supplementary feeding for both treatments ( P<0.01), due to increases in both DM content and the diameter of stem consumed. Reproductive rate was low in the control ewes (121 lambs born/100 ewes mated), and poplar supplementation increased ewe reproductive rate by approximately 20 and 30% units for the low and high treatment groups, respectively, compared to the control group, at scanning, lambing, docking and weaning. The increase in reproductive rate in supplemented ewes was due to increases in both conception rate and fecundity, with a higher proportion of pregnant ewes, and a higher proportion of multiple pregnancies, in the supplemented groups. Ewes in the high and low treatments lost slightly less LW (−67 and −71 g/day versus −82 g/day; P<0.05) and BCS (−0.78 and −1.27 units versus −1.31 units; P<0.05) as a result of poplar supplementation, but these differences did not occur in the post-treatment period. There were no treatment effects on wool production or staple length, and only small treatment effects on the LW of single- and twin-born lambs at birth and weaning. Poplar cuttings are a beneficial supplement for increasing the reproductive rate of ewes grazing drought pasture during the pre-mating and mating periods. Poplar supplementation increased intakes of DM, metabolisable energy (ME) and crude protein (CP), and increased the estimated g CP/MJ ME eaten during the mating period. Increased concentrations of total N, CT and water-soluble carbohydrate (WSC) in the diet of supplemented ewes would also be likely to increase outputs of undegradable dietary protein and microbial protein from the rumen, per unit of CP consumed. A combination of these mechanisms, especially the likely increased absorption of protein, probably explains the increased ewe reproductive rate from poplar supplementation.

The effect of different levels of poplar (Populus) supplementation on the reproductive performance of ewes grazing low quality drought pasture during mating

A grazing experiment, conducted for 71 days from 31 January to 12 April in the late summer/autumn of 2001 at Massey University’s Riverside Farm, in Masterton (New Zealand), compared the effect of poplar supplementation (Populus deltoides × nigra, clone Veronese), during mating, on ewe production and reproduction when grazing low quality drought pasture. A rotational grazing system with 300 mixed age Romney ewes (57.1±0.68kg) was used, with 100 ewes per treatment. All ewes were offered 0.70 kg dry matter (DM)/day of low quality pasture, containing 84% dead matter, with pre- and post-grazing pasture masses of 1040 and 531 kg DM/ha. Ewes were randomly allocated to three treatment groups, being: high supplementation, low supplementation and control. The high and low treatment groups were offered 1.50 kg/ewe/day (fresh) and 0.75 kg/ewe/day (fresh) poplar cuttings, respectively. The effect of poplar supplementation on liveweight (LW) and body condition score (BCS) change; reproductive rate at pregnancy scanning, lambing, docking and weaning; and wool production and staple length was measured. The poplar diet selected contained 22 g/kg DM of phenolic glycosides and higher levels of nitrogen (N; 28.4 g/kg DM versus 17.8 g/kg DM) and condensed tannin (CT; 7.0 g/kg DM versus 1.5 g/kg DM) and was of higher organic matter digestibility (0.66 versus 0.52) than the pasture diet selected. Voluntary DM intake of poplar progressively increased with time of supplementary feeding for both treatments (P<0.01), due to increases in both DM content and the diameter of stem consumed. Reproductive rate was low in the control ewes (121 lambs born/100 ewes mated), and poplar supplementation increased ewe reproductive rate by approximately 20 and 30% units for the low and high treatment groups, respectively, compared to the control group, at scanning, lambing, docking and weaning. The increase in reproductive rate in supplemented ewes was due to increases in both conception rate and fecundity, with a higher proportion of pregnant ewes, and a higher proportion of multiple pregnancies, in the supplemented groups. Ewes in the high and low treatments lost slightly less LW (−67 and −71 g/day versus −82 g/day; P<0.05) and BCS (−0.78 and −1.27 units versus −1.31 units; P<0.05) as a result of poplar supplementation, but these differences did not occur in the post-treatment period. There were no treatment effects on wool production or staple length, and only small treatment effects on the LW of single- and twin-born lambs at birth and weaning. Poplar cuttings are a beneficial supplement for increasing the reproductive rate of ewes grazing drought pasture during the pre-mating and mating periods. Poplar supplementation increased intakes of DM, metabolisable energy (ME) and crude protein (CP), and increased the estimated g CP/MJ ME eaten during the mating period. Increased concentrations of total N, CT and water-soluble carbohydrate (WSC) in the diet of supplemented ewes would also be likely to increase outputs of undegradable dietary protein and microbial protein from the rumen, per unit of CP consumed. A combination of these mechanisms, especially the likely increased absorption of protein, probably explains the increased ewe reproductive rate from poplar supplementation.

Daily and alternate day supplementation of urea or biuret to ruminants consuming low-quality forage: I. Effects on cow performance and the efficiency of nitrogen use in wethers.

Two experiments were conducted to determine the influence of supplemental nonprotein N (NPN) provided daily (D) or every other day (2D) on ruminant performance and N efficiency. Treatments included an unsupplemented control (CON) and a urea (28.7% CP) or biuret (28.6% CP) supplement provided D or 2D at 0700. In Exp. 1, five wethers (39 +/- 1 kg BW) were used in an incomplete 5 x 4 Latin square with four 24-d periods to determine the influence of supplemental NPN source and supplementation frequency (SF) on the efficiency of N use in lambs consuming low-quality grass straw (4% CP). The amount of CP supplied by each supplement was approximately 0.10% of BW/d (averaged over a 2-d period). In Exp. 2, 80 Angus x Hereford cows (540 +/- 8 kg BW) in the last third of gestation were used to determine the effect of NPN source and SF on cow performance. The NPN treatments were formulated to provide 90% of the estimated degradable intake protein requirement. The supplemented treatments received the same amount of supplemental N over a 2-d period; therefore, the 2D treatments received double the quantity of supplemental N on their respective supplementation day than the D treatments. In Exp. 1, total DM, OM, and N intake; DM, OM, and N digestibility; N balance; and digested N retained were greater (P < 0.03) for supplemented than for CON wethers, with no difference (P > 0.05) between NPN sources or SF. Plasma urea-N (PUN) was increased with N supplementation compared with CON (P < 0.01), and urea treatments had greater PUN than biuret (P < 0.01). In addition, PUN was greater (P = 0.02) for D than for 2D treatments. In Exp. 2, pre- and postcalving (within 14 d and 24 h after calving, respectively) cow weight and body condition score change were more positive (P < 0.05) for supplemented groups than for CON. These results suggest that supplements containing urea or biuret as the primary source of supplemental N can be effectively used by lambs and cows consuming low-quality forage, even when provided every other day.

The effect of protein intake on performance of cows in hot environmental temperatures.

Two trials were conducted with cows in commercial herds during midlactation to evaluate the effect of dietary crude protein (CP) concentration on the production, composition, and efficiency of milk production under hot ambient conditions. Cows were group-fed in trial 1, which was conducted in two herds, and were fed individually in trial 2. The respective average ambient temperature, relative humidity, and temperature-humidity index (THI) were 31 degrees C, 45%, and 78 in trial 1 and 27 degrees C, 70%, and 76 in trial 2. Cows were cooled by forced evaporative means six times daily in trial 1 and three times daily in trial 2. Dietary CP was 15.3 or 17.3% of dry matter (DM) in trial 1 and 15.1 or 16.7% of DM in trial 2. The respective ratios of rumen-degradable organic matter (RDOM) to rumen-degradable protein were 5.3 and 4.8 for the low CP (LP) and high CP (HP) diets. Average DM intake, milk yield, and milk fat and protein concentrations were 22 and 23 kg/d, 34 and 35 kg/d, 3.1 and 3.4%, and 3.2 and 3.1% in trials 1 and 2, respectively, and were similar among diets in both trials. The resultant calculated milk protein efficiency ratio and overall CP efficiency were 0.31 and 0.32 for the LP diets and 0.28 and 0.29 for the HP diets. In cows fed the LP diet, diet rumen ammonia was lower in trial 1, and milk urea N was lower in trial 2. The BW change was higher in trial 1, and tended to be higher in trial 2, with the LP diets. Changes in body condition score in trials 1 and 2 tended to be higher with the LP diets. It was concluded that a dietary CP content of 15.3% is adequate to maintain production in heat-exposed dairy cows producing 35 kg of milk/d, provided that the forced evaporative cooling and the ratio of RDOM to rumen-degradable protein is appropriate

Heritability and correlations for body condition score and dairy form within and across lactation and age.

The objectives of the current study were to investigate the relationship between body condition score (BCS) and dairy form and changes in genetic parameters for BCS and dairy form within and across lactations and age. Body condition score and dairy form were obtained from the Holstein Association USA, Inc. Records were edited to include those cows classified between 24 and 60 mo of age and between 0 and 335 d in milk (DIM). A minimum of 20 daughters per sire and 15 cows per herd-classification visit were required. The dataset consisted of 135,178 records from 119,215 cows. Repeatability, multiple trait, and random regression models were used to analyze the data. All models included fixed effects for herd-classification visit, age within lactations 1, 2, and 3 or higher, and 5th-order polynomials for DIM. Random effects included sire and permanent environment for all models. Random regression models included age at classification nested within sire or DIM and lactation number nested within sire. Genetic variance for both BCS and dairy form was lowest in early lactation and highest in midlactation. Genetic correlations within and across lactations were high. The genetic correlation between DIM 0 in lactation 1 and DIM 305 in lactation 3 was estimated to be 0.77 for BCS and 0.60 for dairy form. The genetic correlation estimate between 30 mo of age at classification and 50 mo of age at classification was 0.94 for both dairy form and BCS. The repeatability models appeared to generate accurate evaluations for BCS or dairy form at all ages and stages of lactation.

The value of safflower ( Carthamus tinctorius) hay and silage grown under Mediterranean conditions as forage for dairy cattle

The value for dairy cattle of safflower grown under Mediterranean condition was investigated in two experiments. In experiment 1, safflower hay was given ad libitum as sole food to four dry dairy cows. The DM ingested from hay was of medium CP and NDF contents (148 and 406 g kg −1, respectively). Values of in vivo and in vitro Tilley and Terry DM digestibility were 723 and 646 g kg −1 DM, respectively. In the second experiment, 19 cows were fed a total mixed ration (TMR) including 4 kg (as DM) of corn plus wheat (CW) silage, and another 19 received the same TMR, with safflower silage (S) substituted for CW silage, on the same DM basis, for 62 days. Diets were of similar NDF content (314 and 331 g kg −1 DM, for CW and S, respectively), but cows fed S consumed less DM than those fed CW (20.2 and 22.5 kg, P<0.02). Milk production (30.2 kg day −1), and the contents of fat (35.4 g kg −1), lactose (46.4 g kg −1), and urea (0.32 g kg −1) were similar between groups. Milk CP tended to be lower in S than in CW (31.6 and 33.6 g kg −1, respectively, P=0.07). Changes in body live-weight and condition score were not affected by diet. Safflower silage has the potential for widespread adoption as a feed in Mediterranean countries, if special characteristics such as protein degradability are taken into account to optimize its inclusion in TMRs.

Changes in body condition score and in its genetic variation during lactation

The foundation of the complex of production efficiency and metabolic stress of lactating cows is the dynamics of energy balance (EB) during lactation, for which body condition score (BCS) may be a useful monitoring tool. Energy balance, or imbalance, is the difference between energy expenditure including yield and energy sources from intake nutrients and mobilized body reserves. Both milk yield and dietary intake, their amounts and compositions, can be measured readily and frequently, at least on experimental farms, but body reserves cannot be. Potentially, BCS can be used to indicate the mobilization and deposition of body reserves during lactation. This paper examined changes in BCS during lactation in different breeds, parities and feed levels. Also examined were changes in additive genetic and other variance components of BCS during lactation. Ample additive genetic variation in BCS was found to allow for fruitful genetic selection. If genetic selection is to be practiced, it appeared that shape of the curves during lactation in BCS could be changed genetically. Body condition score assessments were highly correlated within parity and between parities. Strategically, the best period to score a cow's body condition during lactation appeared to be the recovery period from negative energy balance, during which the greatest variances were observed.

Plasma concentrations of leptin, insulin-like growth factor-I, and insulin in relation to changes in body condition score in heifers1

The objective of this study was to determine the relationships among plasma concentrations of leptin, insulin, and IGF-I with dynamic changes in body condition scores (BCS) in heifers. Nineteen Zebu-Brown Swiss crossbred heifers, 24 to 30 mo old, weighing 322 ± 9 kg, and with an initial BCS of 2.6 ± 0.11 (range = 1 to 9) were used. Heifers were fed 60% of their maintenance requirements until they reached a BCS of ≤2. Heifers were then maintained at that level for 25 d, after which they were fed to gain 1 kg of body weight daily until a BCS of 6 was reached. Heifers were weighed weekly and BCS was measured every 2 wk. Plasma samples were collected twice weekly, and leptin and insulin were determined by RIA. An immunoradiometric assay was used to measure IGF-I from one sample every 2 wk. Plasma concentrations of leptin were positively correlated during nutritional restriction (NR) and weight gain (WG) periods with BCS (r = 0.47 for NR, and r = 0.83 for WG; P < 0.01) and body weight (r = 0.40 for NR, and r = 0.78 for WG; P < 0.01). Plasma concentrations of leptin decreased during nutritional restriction (P < 0.01) as BCS decreased. During weight gain, leptin concentration increased at BCS 3 and thereafter for each integer change in the BCS. Regression analysis showed that changes in body weight affect leptin concentrations within a given BCS. There was a decrease in IGF-I as BCS declined (P < 0.01). During weight gain, by contrast, IGF-I increased significantly (P < 0.01) with every unit change in body condition up to BCS of 4 and plateaued thereafter. Insulin concentrations did not change during nutritional restriction when BCS decreased from 3 to 1. However, once the diet was improved, there was a large increase in insulin concentrations in heifers with BCS 1 (P < 0.01). Among heifers of BCS 2 and 3, insulin did not differ and was lower than in heifers of BCS 1 (P < 0.01). Insulin increased (P < 0.01) among heifers at BCS 4 to 6. Leptin was positively correlated (P < 0.01) with both IGF-I (r = 0.34 for NR, and r = 0.36 for WG) and insulin (r = 0.18 for WG). Insulin was correlated with IGF-I (r =0.60; P < 0.01). During nutritional restriction, insulin did not correlate with leptin (r = −0.05), BCS (r = −0.03), or IGF-I (r = 0.07). It was concluded that leptin serves as a dynamic indicator of body condition in heifers, as well as an indicator of nutritional status.

Plasma concentrations of leptin, insulin-like growth factor-I, and insulin in relation to changes in body condition score in heifers.

The objective of this study was to determine the relationships among plasma concentrations of leptin, insulin, and IGF-I with dynamic changes in body condition scores (BCS) in heifers. Nineteen Zebu-Brown Swiss crossbred heifers, 24 to 30 mo old, weighing 322 +/- 9 kg, and with an initial BCS of 2.6 +/- 0.11 (range = 1 to 9) were used. Heifers were fed 60% of their maintenance requirements until they reached a BCS of < or = 2. Heifers were then maintained at that level for 25 d, after which they were fed to gain 1 kg of body weight daily until a BCS of 6 was reached. Heifers were weighed weekly and BCS was measured every 2 wk. Plasma samples were collected twice weekly, and leptin and insulin were determined by RIA. An immunoradiometric assay was used to measure IGF-I from one sample every 2 wk. Plasma concentrations of leptin were positively correlated during nutritional restriction (NR) and weight gain (WG) periods with BCS (r = 0.47 for NR, and r = 0.83 for WG; P < 0.01) and body weight (r = 0.40 for NR, and r = 0.78 for WG; P < 0.01). Plasma concentrations of leptin decreased during nutritional restriction (P < 0.01) as BCS decreased. During weight gain, leptin concentration increased at BCS 3 and thereafter for each integer change in the BCS. Regression analysis showed that changes in body weight affect leptin concentrations within a given BCS. There was a decrease in IGF-I as BCS declined (P < 0.01). During weight gain, by contrast, IGF-I increased significantly (P < 0.01) with every unit change in body condition up to BCS of 4 and plateaued thereafter. Insulin concentrations did not change during nutritional restriction when BCS decreased from 3 to 1. However, once the diet was improved, there was a large increase in insulin concentrations in heifers with BCS 1 (P < 0.01). Among heifers of BCS 2 and 3, insulin did not differ and was lower than in heifers of BCS 1 (P < 0.01). Insulin increased (P < 0.01) among heifers at BCS 4 to 6. Leptin was positively correlated (P < 0.01) with both IGF-I (r = 0.34 for NR, and r = 0.36 for WG) and insulin (r = 0.18 for WG). Insulin was correlated with IGF-I (r = 0.60; P < 0.01). During nutritional restriction, insulin did not correlate with leptin (r = -0.05), BCS (r = -0.03), or IGF-I (r = 0.07). It was concluded that leptin serves as a dynamic indicator of body condition in heifers, as well as an indicator of nutritional status.

Predicting nutritional requirements and lactation performance of dual-purpose cows using a dynamic model

A dynamic application of the Cornell Net Carbohydrate and Protein System (CNCPS) model was developed to predict annual cycles in animal nutrient requirements and performance of dual-purpose (milk and beef) cows. Interactions from mobilisation and repletion of body tissue reserves and feed biological values are accounted with a time step of one day, which considers physiological status of the animal, variation in dietary composition, and other environmental factors. This outcome was achieved by modifying the input and output structure of the CNCPS version 4.0 to compute body weight and changes in body reserves based on predicted milk production, intake of feed dry matter, and energy balance. The supply of metabolisable energy from dietary intake is supplemented by tissue mobilised to support milk synthesis in early lactation; body tissue is repleted when energy balance is positive. Predicted animal nutrient requirements, milk production, dry matter intake, and changes in body weight and body condition score over the reproductive cycle were consistent with patterns and values in published reports and field observations in the Gulf Coast of Mexico case study region. Our simulations showed that a dynamic application of the CNCPS facilitates more accurate monitoring and management of cyclic changes in energy and protein balances over the calving interval of dual-purpose cows, which can help producers to achieve productivity and profitability goals.

Comparative Supplemental Value of Noug (Guizotia abyssinica) Meal for Fattening Draught Oxen Fed Teff (Eragrostis teff) Straw

Mengistu, A. 2003. Comparative supplemental value of noug (Guizotia abyssinica) meal for fattening draught oxen fed teff (Eragrostis teff) straw. J. Appl. Anim. Res., 24: 85–88. Twenty-four draught Arsi (Bos indicus) oxen of 7–8 years age and similar body condition were randomly allocated to four groups and individually fed on one of the four diets: teff (Ergrostis teff) straw alone (D-1), D-1 supplemented with 2 kg/head/day of noug (Guizotia abyssinica) meal (D-2), D-1 supplemented with 1.5 kg maize plus 73 g urea/head/day (D-3) and D-1 supplemented with 1 kg noug meal plus 1 kg molasses/head,/day (D-4). Straw intake was not affected (P>0.01) by treatments but average daily gain, straw utilization efficiency and change in condition score were the highest for the D-2 group. It is concluded that noug meid replaces maize grain with enormous cost advantage when supplemented to teff straw.

Effects of Different Transition Diets on Dry Matter Intake, Milk Production, and Milk Composition in Dairy Cows

The primary objective of this study was to evaluate the effect on dry matter intake (DMI), milk yield, milk composition, body weight (BW), and body condition score (BCS) change of cows offered diets differing in energy density in the last 4 wk of gestation and in the first 8 wk of lactation. Three diets (grass silage:straw, 75:25 on a dry matter basis (SS), grass silage (S), and grass silage + 3kg concentrate daily (C)) precalving, and two diets (4kg [LC] or 8kg [HC] concentrate daily + grass silage ad libitum) postcalving were combined in a 3×2 factorial design. Sixty Holstein-Friesian cows entering their second lactation were blocked according to expected calving date and BCS into groups of six and were then allocated at random to the treatments. Individual feeding started 4 wk prior to the expected calving date and measurements were made until the end of the 8th wk of lactation. Mean DMI differed between each of the precalving treatments (7.4, 8.1, and 9.9kg/d for SS, S, and C, respectively) in the precalving period. The DMI also differed between SS and C for wk 1 to 8 (13.5 and 14.2kg/d) postcalving. Postcalving, milk (24.2, 26.2, and 28.2kg/d), fat (933, 1063, and 1171g/d), and protein (736, 797, and 874g/d) yields differed between SS, S, and C, respectively. The BCS changes differed between SS and C (−0.09 and 0.12 of a BCS) in the precalving period and between SS and S compared with C (0.02, 0.06, and −0.26 of a BCS) for wk 1 to 8 postcalving. The BW change differed between SS and S compared with C in both wk 1 to 4 (−0.23, −0.37, and −1.25kg/d) and wk 1 to 8 (0.18, 0.10, and −0.58kg/d) postcalving. The BW and BCS were lower at calving for cows on SS compared with C. The greater amount of concentrate supplement postcalving increased DMI, yields of milk, fat, and protein and decreased BW loss in the first 8 wk of lactation. In conclusion, these results indicate that a greater energy density diet in the final 4 wk of the dry period improves cow production in early lactation.

Effect of feeding calcium salts of long-chain fatty acids, from palm fatty acid distillate or soybean oil, to high producing dairy cows on milk yield and composition, and on selected blood and reproductive parameters

Calcium salts of long-chain fatty acids from palm fatty acid distillate (CaPFAD) and soybean oil (CaSOFA) were compared using 14 first lactation and 26 multiparous Holstein cows housed in a free-stall barn. It was hypothesized that if replacing CaPFAD with CaSOFA, a rich source of linoleic acid, could result in increased conjugated linoleic acid (CLA) content in milk without losing the lactational and reproductive benefits of feeding CaPFAD, this would be beneficial to the dairy industry and public health, as well as potentially enhance the consumption of dairy products. Cows were group-fed one of two total mixed rations (TMR) containing 1.7% CaPFAD or CaSOFA (DM basis) for ad libitum intake following recommendations from the manufacturer of the fat supplements. Fatty acid profiles (g/100 g of fatty acid) of CaPFAD and CaSOFA, respectively, were 16:0: 48.1, 12.1; 18:0: 4.27, 5.34; 18:1: 35.7, 23.9; and 18:2: 8.9, 51.2. Cows spent about 45 days in the fresh group, after which they were moved to high producing group where they stayed up to 10 weeks post-partum within their treatment assignments. The TMR (DM basis) were 50:50 forage:concentrate for both the fresh group and high producing group cows and contained (DM) 28% NDF and 18% CP. There were no treatment differences in milk yield, milk fat percentage, milk CLA content, milk true protein percentage, milk lactose percentage, milk urea N, linear somatic cell count and change in body condition score. Cows fed CaSOFA produced milk containing a higher content of 18:1(t) ( P<0.01) and 18:2 ( P<0.01) during weeks 8–10 post-partum, and had smaller follicles at ovulation ( P=0.03). Cows had similar concentrations of serum nonesterified fatty acids and β-hydroxybutyrate, and similar 30 days uterine score, days to first ovulation, days to first service, first service conception rate and progesterone concentration. In conclusion, while cows fed CaSOFA had similar lactational and reproductive performance to cows fed CaPFAD, the anticipated beneficial effect of enhancing content of CLA in milk was not realized from feeding CaSOFA at 1.7% of expected DM intake.

Genetic Evaluations of Dairy Bulls for Daughter Energy Balance Profiles Using Linear Type Scores and Body Condition Score Analyzed Using Random Regression

The difference in body lipid between the start and end of lactation represents the body energy lost (or gained) in support of maintaining lactation including the nonproduction components of lactation. This source of energy is ignored in current genetic evaluations for production for dairy sires. The depletion and accretion of body tissue creates a pattern of body energy content over time that is, in part, under genetic control. Using random regression and field data, we modeled changes in body condition score (BCS) and liveweight, predicted from linear type traits, on first parity cows to produce daily breeding values of their sires for energy balance. These curves show that sires differ in the way their daughters lose and regain body energy throughout lactation. For all sires, the overall mean maximum daughter body energy loss was 1499 MJ (SD = 144 MJ) and occurred at d 99 (SD = 12.8 d) of lactation and the mean total daughter body energy loss at d 305 of lactation was 779 MJ (SD = 224 MJ). In this study, the profiles of body energy loss indicate that daughters of most sires lost body energy before d 150 and then recovered body energy, whereas the daughters of a few sires continued to lose body energy through to the end of lactation. Some sires with high merit for production may have daughters with body tissue mobilization profiles associated with poorer health and fertility leading to higher costs. A method of accounting for this cost could be to correct yield for body tissue mobilization. Deducting kilograms of milk from the breeding value for milk for each sire, equivalent in energy content to the body energy lost, resulted in a correlation of 0.98 between the ranking of sires for milk kilograms before and after adjustment. However, some sires changed rank by large amounts, the largest being +355 positions. Breeding values for energy balance can be calculated from single observations of BCS and linear type traits on daughters of a sire; data that can routinely be collected in national conformation assessment schemes.

Effect of the amount of body condition loss from the dry to near calving periods on the subsequent body condition change, occurrence of postpartum diseases, metabolic parameters and reproductive performance in Holstein dairy cows

We investigated the effect of body condition loss from the dry to near calving periods on the subsequent body condition change, the occurrence of postpartum diseases, the serum metabolic parameters total cholesterol, triglyceride, glucose, and urea nitrogen and the number of days to first breeding after calving in Holstein dairy cows. Body condition scoring (using a 5-point scale with quarter-point divisions) was performed on 67 pregnant Holstein dairy cows. Cows were scored once for body condition during the dry period (prepartum day 35±16), near calving (postpartum day 5±4), and subsequently at months 1 (±day 4), 2 (±day 5), 3 (±day 5), and 4 (±day 4) of lactation. At the same time, blood samples were collected to evaluate serum total cholesterol, triglyceride, glucose and urea nitrogen concentrations. Cows were categorized based on body condition loss from the dry to near calving periods into two groups: the moderate condition loss group (0–0.75 points, n=41), or the marked condition loss group (1.0–1.5 points, n=26). Regular reproductive health examination was conducted by the same investigator once a week. The marked condition loss group lost more body condition ( P<0.01) than the moderate condition loss group consistently until month 1 of lactation. The recovery of body condition in the marked condition loss group was more delayed ( P<0.01) than in the moderate condition loss group from months 1 to 4 of lactation. The occurrence of metritis and metabolic diseases (including abomasal displacement, milk fever, ketosis) was greater ( P<0.01) in the marked condition loss group (62 and 23%) than in the moderate condition loss group (27 and 2%), respectively. The total cholesterol concentration was lower ( P<0.05) in the marked condition loss group (167±5.3 mg/dl) than in the moderate condition loss group (183±5.8 mg/dl) at month 1 of lactation, however, the cholesterol levels at the other periods were not different ( P>0.05) between the two groups. The triglyceride, glucose, and urea nitrogen concentrations were not different ( P>0.05) from the dry period to month 4 of lactation between the two groups. The number of days to first breeding after calving was longer ( P<0.05) in the marked condition loss group (103±7.8 day) than in the moderate condition loss group (87±5.3 day). We conclude that marked body condition loss from the dry to near calving periods results in the increased occurrence of postpartum metabolic and reproductive diseases, decreased serum total cholesterol concentrations at month 1 of lactation and a longer interval to first breeding after calving in Holstein dairy cows, probably due to the more severe energy deficit reflected by unfavorable body condition score change during early lactation.